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9zqf1f | how is it that a console doesn’t need to get its hardware updated for new games? | So for example, some games might not work on a computer built at the same time as the console (let’s say a PS4) how is it that the PS4 would be able to run new games that came out recently perfectly fine, but a computer built during the time of the PS4’s release may lag behind and require new hardware? | Technology | explainlikeimfive | {
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"Because a game is specifically designed to work with that hardware setup. A computer may have hundreds of different combinations of processor, graphics card, etc, so pc games are designed to work for a generic baseline of what they expect a majority of players to have at their disposal- they won't ever be designed specifically for the best of the best components, because that would severely limit their market. But a console doesn't have to limit themselves like that, because they know exactly what equipment it will be played on and can fine tune it for that build."
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9zqogz | How does internet security work and how can hackers steal some info, like credit card numbers or medical records? | Technology | explainlikeimfive | {
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"Internet \"forces\" computers to be connected to each other; banks have to talk to each other to transfer money, hospitals have to talk to each other to transfer medical records that are needed, etc. \"Security\" is about making sure that only authorized accounts get access to the data. ID's, Passwords, log in policies, address-based restrictions, etc. It gets very complicated, because for example a hospital can have hundreds of doctors, nurses, and other staff who need access, so you have hundreds of accounts that have to have access. Hackers find a way to break in, either by stealing passwords, or by social engineering (they call someone pretending to be their boss or a different doctor and in a hurry to get in or the patient will die, and ask for a password), or by using bugs in the system that haven't been fixed yet."
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9zt5ja | What exactly happens when booting up a device such as computer or a smartphone and why isn't it instant? | Technology | explainlikeimfive | {
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"Tons of things. I might miss some steps. Very generally: there's some code burned into ROM on the device that activates when power is first applied. It runs a power-on self test (POST). If everything checks out, it looks for an Operating System (OS) image. It might have to use some fancy math to verify that the OS hasn't been tampered with. Once it sees that everything is OK, it start to load the OS into memory which takes some amount of time. The OS itself will have many many things it does at startup, for example checking the disk/SSD structure to make sure the files haven't got damaged. It also loads a lot of the basic programs that make the system work. Each of those takes time and some of the steps are dependent on the previous steps completing, so that adds even more time."
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9ztfur | How can LEDs be brighter than incandescents while not being as luminus? | For example, incandescent Christmas lights illuminate the area around them while LEDs seem brighter, but only as tiny points of light. | Technology | explainlikeimfive | {
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"\"Luminous flux\", measured in lumens, is the total amount of visible light coming from a bulb \"Luminous intensity\", measured in candelas, is the amount of visible light going from a bulb in a particular direction. So imagine an LED and an incandescent bulb that have the same number of lumens. The incandescent probably sends its light roughly equally in all directions; it will appear equally bright from whichever angle you view it. LEDs are typically focused so, if you look at them head on, they will look brighter. If you look at them from a different angle they will look dimmer. So the number of candelas from a light source can vary, even if the number of lumens is the same. It's the same with flashlights or searchlights: they can have a huge number of candelas (candle power in old units) even with relatively weak (low lumen) bulbs, because the beam is tightly focused. Unfocused lights look dimmer to the eye, but their light is spread more evenly around and does a better job of lighting up everything nearby."
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9zu8gs | Before MIDI, how did musicians time the beats exactly right? | When I listen to something old like Thriller, I notice that the beats of the drums seem to be timed exactly right with the rhythm, with the same amount of time between each beat. Or so it seems. Because now, with MIDI, you can have the instruments timed to be exactly right with the rhythm, but Thriller was made before MIDI, and now I'm wondering how the drummers and musicians played their instruments exactly on beat and to the rhythm. There's a website called Got Rhythm where it tests to see if you can maintain the tempo/rhythm of a drum beat even after it fades away, and it would always tell me that most of my beats were slightly off tempo. Now I'm wondering how musicians timed things to be exactly on tempo before MIDI. | Technology | explainlikeimfive | {
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"Practice by drummers. The main function of drums is to keep rhythm so any drummer worth their salt practices countless hours with a metronome to hone this skill. It’s also not uncommon for musicians(drummers too) to record with a click track to keep them on tempo. Also, the 70s is when programmable drum machines started to get really big, so even though it wasn’t MIDI, it’s programmed to land precisely on the beat.",
"The traditional method, for musicians lacking a natural great sense of timing, was to use a metronome. That's a swinging pendulum, or electronic device, that automatically generates a regular beat.",
"Don't forget, Michael Jackson had the ability to pull the best studio musicians possible. Some are better than others, and since he could afford the best, he had the best. And the best have a great internal sense of time.",
"The drummer is often listening to a click track on their headphones while they are being recorded. The click track keeps them in time."
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9zuxp1 | why do some phone chargers charge more quickly than others? | I’m sitting in a gas station currently dreading having to charge my phone because a) I don’t have a car charger and b) compared to my friends, this charger seems to take extremely long to give my phone a charge. Why is that? Thanks! | Technology | explainlikeimfive | {
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"1.) Some charging sources can put out a higher current than some others. 2.) Some charging sources may support an additional fast charging protocol that your phone also supports, allowing a higher voltage and/or current along the cable. 3.) You might be using a cable with a higher resistance."
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9zvmje | How do ships sail against the wind? | Without some other source of power like engines or oars? | Technology | explainlikeimfive | {
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"They perform a series of \"tacks\" where they don't sail directly into the wind but sail at an incident angle while steering the boats rudder so the boat makes headway (albeit more slowly than downwind sailing) then they reverse the sail and rudder to the opposite incident angle so on average they are sailing toward the desired destination. By alternating these courses they make wayvon average to the direction desired.",
"Sails work more like wings than parachutes when used properly The triangular sails billow outward to one side and create an airfoil. The air flows over the curved sail, creating a low pressure section in front of the sail just like over a wing. This low pressure region creates \"lift\" which pulls the sail, and the boat, towards it This effect can let a sailboat sail faster than the wind behind it because once wind is rapidly flowing over the sail it's somewhat self sustaining Big ships with square sails couldn't sail nearly as close into the wind. The square sails behave as you'd expect, acting like a parachute which catches the air and pulls the ship along. They're good for \"running\" with the wind, but not very good for slow winds or sailing at a tight angle to the wind"
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9zwatb | Just how dangerous is it to use a Huawei device? | There’s been [a lot of news reports recently]( URL_0 ) about Huawei spying. I just got a Huawei laptop. How exactly can Huawei spy on me? Like, what can they do and why has nobody been able to search their products and answer this definitively? | Technology | explainlikeimfive | {
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"Well, 99% of computer makers can spy on you, if they want to. Google and Amazon do all the time. The question is what they DO with the information they have on you. The fear is that **Huawei,** as a Chinese company, has a direct interest in keeping the info on you, and providing direct access to the Chinese Government.",
"So let's theorize. What does Chinese gov care about you personally? Probably nothing unless you're a military or political or high commercial asset. That can be convinced or pressured into leaking that info. That's some spy games shit. What can the Chinese gov learn about trends in patterns of behavior and which influences affect US populations. Is it political ideals? Is it economic reform? That can be datamined and turned into actionable intelligence. What economic trade policies will have more impact. What political battles will cause more turmoil. Is it Tibetan/Uighur human rights or trade tariffs? The same is being done by the US gov and the Russians of their own people as well as each others. The difference is...the Chinese aren't buying US or Russian technologies by the boatload."
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9zwt72 | What is MIDI | Ive been looking up keyboards and synths to buy recently and I keep seeing "MIDI" mentioned. But no explanation or context is given. Is it a format? A port-type? An accessory? What does it do? Whats it for? I cant figure out any of these things. | Technology | explainlikeimfive | {
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"An acronym for Musical Instrument Digital Interface, It's a communication standard for musical hardware. The standard allows two products, from two different manufactures, to exchange performance data using a common language. MIDI is used to control music equipment, lighting equipment, and even video games. It's a fast transferring digital signal that allows performance data to be layered using multiple channels or separated using multiple ports. MIDI messages can be defined by a MIDI port and/or a MIDI channel. Each port has 16 different channels that can be used to pass data. MIDI ports are often unique hardware paths, indicated by a 5-pin DIN connectors. MIDI ports can have their own hardware input and output or all ports can be handled by a single USB connection. MIDI is transferred using two common cables/connectors. Most hardware and external sound modules will use MIDI 5-pin DIN inputs and outputs to transfer MIDI. More recently, due to the music software explosion, MIDI is being sent over a USB cable. [For more information]( URL_0 )",
"Put really simply, imagine you have two keyboards. Perhaps you want to play the piano patch on your first keyboard and simultaneously play the supersaw pad on your other keyboard. Without MIDI, you need to put both keyboards on a double decker stand, and play one with your right hand and the other keyboard with your left. With MIDI, you just play one keyboard, and your key presses get sent to both keyboards and both keyboards produce their respective sounds."
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9zxhmv | Why does hold music sound so terrible? In this age of UHD sound how come hold music sounds like it's being played through sock in a wind tunnel? | Technology | explainlikeimfive | {
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"Phone lines are designed to carry voice and not music. Humans can hear sounds from 30Hz to 22kHz but can only make sound from 300Hz to 3000Hz with out voice. So you need very different sample rates for the voice and music. This means that phone lines works terribly for music as it cuts out most of the high pitches and you are left with just the bass. Secondly as phone lines gets more and more digital we find even more ways to save on bandwidth by compressing the sounds so they take up less space. However this process uses very different compression algorithms for voice then for music. So the compression algorithms will add a lot of noise to the music as it is not designed for music. Adding to this you can have different compression for different sections of the lines as the line passes through different phone operators. So you get different types of distortions each time.",
"The phone network can only transmit a certain amount of data in total at a given time. Each call uses up a share of that data. To make calls require less of it, we compress the audio in certain ways. The simplest and first technique is to cut off all the high-pitched and low-pitched sounds, leaving just the medium. Human speaking voices only use this medium so it sounds fine for ordinary speaking and saves a *ton* of data, letting us fit more people onto the phone network at once. It only becomes really noticeable when we try to play music -- which uses a much bigger variety of high pitched and low pitched sounds -- over it. We could have high quality musical audio calls if we wanted, but it means phone towers would hit their max capacity much faster and fewer calls would go through. It's just not worth it for better hold music. Added to this is the fact that the phone networks were designed a long time ago, using audio technologies that are now kind of primitive. Upgrading them *is* possible but means old phones that don't support those newer technologies would stop working. So it's something that gets done very very slowly. Cutting-edge audio compressors like Opus can make 40 Kbps audio files today sound better than 100 Kbps audio files from 20 years ago."
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9zxsjm | If 95% of the ocean hasn’t been explored, how do we know where the deepest point is ? | Technology | explainlikeimfive | {
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"Sonar. We can measure the depths of the ocean with surface boats, but we haven’t dived down physically to explore most places.",
"It depends on your definition of explored. Saying we have not explored 95% of the oceans is using a rather strict definition of the term. We have done a lot of ocean wide exploration using remote sensing technology such as sonars, magnetometer, seismic exploration, and so on. So we know a great deal about the ocean floors even though we have not physically visited them. Because it turns out that most of the ocean floor is a dead, boring, featureless landscape. And considering that you need more advanced technology to get to the bottom of the ocean then for a space mission it is not surprising that we have not bothered to explore most of the ocean. In a similar way we also knew exactly how high mount Everest was after multiple expeditions to the area even though nobody had climbed the mountain. And you can now get accurate maps of the entire surface of the Earth even though the map maker have not visited even half of it. Similarly you can get very accurate maps of the ocean floor.",
"Others have given much better answers about sonar and such but I see it this way: I have only \"explored\" like 5% of Illinois but I am confident that it does not include the highest point in North America.",
"It's been mapped using techniques like Sonar, which send out pings of sound into the depths. The longer the sound takes to return, the deeper it is. Because of this, we know how deep the oceans can get, but we haven't sent submarines into most of it.",
"Users keep mentioning sonar, but interestingly enough the discovery of the deepest point (the Challenger Deep) was [made using a weighted rope]( URL_0 )."
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9zzk7u | how is elevation of cities measured? | Technology | explainlikeimfive | {
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"That's part of [Surveying]( URL_0 ). Technology has progressed (lasers, GPS satellites, etc.), but the easiest method used in the past was you stand in a location where you know your elevation, and you measure the angle (of looking up) at the city, and the distance to the city, and then use trigonometry to find the height of the city. Uses tangent (tan(x)), basically.",
"It makes for a long story because it involved the work of many, many different people, but essentially, by manual surveying. All surveys had to be tied back into some original survey that had a defined sea level elevation. One link at a time, outward from some original point. Actually, often from several different reference points, and this eventually caused a problem because \"sea level\" isn't actually very level or fixed (because of tides and that the earth is not a perfect sphere, and other things). When surveys from different starting points came together, they often had disagreements in terms of elevation, and sometimes not a matter of a couple inches, either. Modern surveying is based on a complex model of the shape of the earth. It is a complicated thing in practice, but it corrects for the fact that the absolute distance from the center of the earth to the surface (where water marks \"sea level\", or level of equal gravity) is not constant. changes by about 21 km from equator to the pole, for one thing (the radius at the pole is about 21 km shorter than at the equator)."
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9zzp8w | What does increasing audio bit size and frequency do? | Technology | explainlikeimfive | {
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"The frequency determines the highest frequency that can be resolved in the signal. This is often called the Nyquist rate. If you sample at twice the frequency of the highest frequency desired in the signal, you can perfectly reconstruct it. However, there are certain signal processing applications where it may be beneficial to *oversample* the signal. This gives you more room to perform various DSP tricks. One of them involves increasing the effective resolution of signal, so you can trade off resolution for frequency to some extent. The resolution is how many different steps of amplitude (loudness) can be resolved. This is primarily important in terms of quantization error. When you render an analog signal into digital terms, you end up with discrete steps instead of a continuous signal. So at any given time, you have a little bit of error between the digital and analog signals. This little bit of error creates broadband noise in your audio stream. For example, 16 bit audio (CD quality) has 96 dB SNR while 32 bit audio has 192 dB SNR. The former would be nearly impossible for a human being to hear while the latter would be absolutely impossible for a human being to hear (192 dB is larger than the human audio range). The drawback to raising these values is that you'll be consuming more processing time/memory for the audio. However, changing these values isn't going to change anything about the *source*. If you're playing an audio file someone else recorded, you can't increase the frequency/resolution of that file and you'll just use whatever it was encoded at. The only reason you'd need to change these values is if you were recording/processing your own audio files."
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a00rwi | How do services like Netflix or Hulu know if an original show is profitable? | Technology | explainlikeimfive | {
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"For those types of services, it's all about new subscribers. If a show generates enough new subscriptions to please the stock holders, it's considered a success. Many shows on these services are not produced in house, locking them in for at least a 2 season run no matter how successful. Netflix does not release viewership numbers to the public, and I doubt they ever will",
"It's all ratings. They are monitoring literally every second of every show that gets watched by everyone. The more eyes on it, the more profitable it is.",
"It's also analytics. They're watching trends on social media to see what shows are in demand and being discussed.",
"They have a choice to buy proven commodities like for example, Star Wars, or something, but those kind of shows/films cost huge money. If they can find a show or film that is having trouble finding an audience, they can buy it up for cheap, fill up their “new arrival” page and claim to be producing new material for their faithful subscribers. If some of them fail miserably, they move on, if they get a hit, they rake in new subscribers."
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a00vha | Who owns domain names? | Why do you have to buy a domain from someone and why do they own it in the first place? | Technology | explainlikeimfive | {
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"Top-level Domain names are leased from the organization that runs the DNS. You pay a yearly fee to maintain control of that Domain name. Companies like GoDaddy are effectively resellers (domain brokers) that you can pay to manage the Domain Name entry. They bill you, and in turn they maintain your domain entry on the DNS. So long as you pay your yearly fee you 'own' the domain name, and have certain rights to it. Even if you forget to pay you often have upwards of a year to get it back. So if you want a domain name, and it's available, you go to one of these brokers and buy it. One catch to this is that many domain names are already 'owned' by someone else. So called Domain Squatters have bought up large numbers of domain names with intent of reselling them for a higher price. These squatters owned hundreds if not thousands of potentially good domain names and sit on them. Hosting crappy websites full of ads that generate enough revenue to pay the yearly fees while they wait for some business to want to negotiate buying one of those domains, often for thousands of dollars."
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a01ft7 | How are gift cards validated and activated at checkout? Are their serial numbers stored in a database and then marked as activated? How are they activated when their numbers haven’t been scratched off? | Referring to the cashier activation of gift cards like Steam or League of Legends cards at checkout to prevent theft | Technology | explainlikeimfive | {
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"Point of sale system (POS) scans a barcode on the gift card. This barcode is specific to the gift card, and allows the card to be identified without the card number or pin. The retailer accepts cash, the POS records a transaction on the retailers ledger. Then, the POS sends the transaction information to the gift card company, this activates the card. Source: worked in retail.",
"Don't over think it. It's no different from your normal bank given credit/debit card. It just comes with a few more restrictions like the kind and location of transactions. It's all. Activation is similar. It just let's the backing financial institution(s) know that this card is now sold so the user can use it. It's often done with some identity check in some countries to ensure the buyer is legit."
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a01jng | My friend was explaining why his PC was so fast and sent me this, “I did 2 2tb hard drives in a raid 0 with my 500gb ssd and and 1tb back up drive”. I have no idea what he’s talking about. | Technology | explainlikeimfive | {
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"That was your friend's response to an inquiry about why his PC is fast? Is he 11? Does he play Fortnite? SSD stands for solid state drive. It is storage that's directly connected to the main unit of the computer making your PC able to access information much faster than normal hard drives. Raid 0 means he has created the same data across multiple storage devices making his PC slightly faster. What's really doing the work is that SSD though.",
"All that given information means is that the person mentioned has a lot of fast storage: a 500gb flash memory SSD, two hard drives in an array with data striped across them (increasing performance but decreasing fault tolerance) and a single drive as a backup location.",
"Normally, a drive can only read/write one thing at a time. It's either recording some data or retrieving some data. SSDs are extremely fast at this to begin with, but they can still only do one thing at a time. RAID 0 takes 2 (or more) drives and acts like they're a single drive that can read/write multiple things at a time. So if you have a game, the load times will be lower because you have 2 drives loading the data instead of one. Now, since drives are just for data storage, this will really only help with load times and won't speed up any actual gameplay. Also, the drives can only read data as fast as the rest of the computer requests it, and SSDs are already extremely fast, so SSDs in RAID 0 will only give a real boost if the rest of the computer is also ridiculously fast.",
"RAID 0 means that you can take two disk volumes of equal size and \"stripe\" them. Since you are limited as to how fast you can read and write to and from a mechanical hard drive or solid state drive, you can set it up where your computer will treat them as one contiguous volume, but go back and forth writing data between them. So anything that needs to be read or written and half is stored on one drive, and half on the other. This effectively doubles your potential read/write speeds. But since they need to work together, you usually do this with identical drives. Size/make/model/firmware/etc. You can do it with different size drives, like a 500GB and a 1TB like your friend did, but either half of that 1TB drive will remain unused, or it will be it's own normal volume. Your friend didn't RAID 0 two 2TB drives, he RAIDed a 500GB and 1TB, which means the total RAID volume is 1TB with 500GB left over, which definitely doesn't add up to 2TB. Also he's mixing solid state and mechanical hard drives, so he's not getting any real performance benefit, and likely torturing that mechanical drive and is going to cause it to fail. Real unfortunate, because if you lose the data on one RAID 0 drive, the data on the other drive becomes unusable junk also. You may have no idea what he's talking about, but neither does he."
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a01lny | How do USB splitter hubs work? How do multiple devices simultaneously transmit signals through a single port without stuttering? | Technology | explainlikeimfive | {
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"They don't simultaneously transmit. Rather, they transmit one at a time. However, USB transmits so quickly that you'll rarely run across situations where it matters. Most USB peripherals - your mouse/keyboard, for example - use a tiny fraction of the available bandwidth. Even mass storage devices don't generally reach the limits of USB transmission speed.",
"Ah, my friend. Welcome to the glorious world of packet switching serial communications networks. Multiple devices connected to the same hub do indeed share the same electrical connections (kind of, essentially), so if you don't want garbled communications only one device can transmit at a time. In USB this is done by having the host control all communications. The role of host is played by the USB controller in your computer. Everything connected to the host is called a device. The host has a method for automatically discovering all devices, and it knows which address on the network belongs to each device. The host directs a certain device at a certain address to transmit, and only then does the device actually transmit. The other part of this is that the host and devices transmit in discrete packets of data. The structure of a packet is exactly defined so that every device knows which part of the packet means what, and most importantly, when the packet ends. So the host can direct one device to transmit, the device transmits a packet (or group of packets), the host waits for the complete packet (or group of packets) to be transmitted, then it directs the next device to transmit. This happens...really fast. If we were going to get carried away...this same idea can be scaled up to larger networks, and even over long distances, say through telephone lines. Then you can develop even more complex protocols that don't even need a host, design faster communications methods, create new ways to transfer large amounts of data and deliver them to people's screens...and you have the internet. Every single part of this is massively complex, but also incredibly cool."
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a03a4m | what the purpose of the black strips of wire/rope that I see from time to time across several lanes of traffic? | Technology | explainlikeimfive | {
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"Those are pneumatic axle counters - there's a traffic study being done for that location, they want to see how many vehicles use that piece of road in a given time. One at a place is necessary, more than one is backups in case one is damaged. Vehicle crosses the rubber tube, the air impulse advances a simple counter in the box off to the side of the road.",
"When I was a kid we would jump on these just to mess with their data. I have no idea if we were successful.",
"If it's what I'm thinking they are basically measuring traffic, how many cars use that stretch of road and at what times etc"
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a04bxn | What happens when a television commercial gets cut off by a different commercial within seconds of the first one starting? | Technology | explainlikeimfive | {
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"You mean what happens afterward or what causes it? The cause is sometimes the local station or cable channel can sell local commercials (AKA spots), but their spot may not start exactly on schedule. You will see whatever spot is running on the network during that time slot. Some networks don't run spots in local spot times. What happens afterward is a discrepancy report is filed and management looks to blame and possibly fire someone. So there is a continuous stream of new, inexperienced, operators who make mistakes. If the correct spot doesn't air or is only partially aired, they don't get paid in full. That can be thousands of dollars."
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a04hd0 | How does NASA learn about far away planets? | Like how do they figure out that some planets are just giant balls of gas? Or how do they determine if there’s water on a planet hundreds of light years away? Or what elements, chemicals, weather conditions, temperatures, etc. can be found on far away planets? | Technology | explainlikeimfive | {
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"You can't see a planet in a telescope, even the best telescope. But you can see stars really really clearly. So you can look at a star and see if it's wiggling around that something must be rotating around it to pull it, so there must be a planet, and from that you can figure out how big of a planet it must be. Likewise if the star gets a tiny bit dimmer every few months on a super regular schedule you can tell a planet is making a teeny tiny eclipse and blocking some of the light. If every time the planet passes in front of the star the color of the light changes a teeny tiny bit you can use that to guess what elements the light must be going through."
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a06oob | If movie projectors project light, how do they project the color black? | Technology | explainlikeimfive | {
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"Movie projectors project light through a reel of film (or at least used to) the black areas are the parts on that film that are less transparent meaning less light get a though... so it looks darker. Which is how you get a contrast high enough for us to perceive it as black."
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a06zoi | Mathematic problems/algorithms that has to be solved by powerful computers? | Hello there, Can anyone explain me how does it actually work and what they are solving? I’ve heard a lot about the most efficient computers that can solve millions of operations at a glance and moreover they are gathering more and more power to solve another problems or whatever it is. So there’s a company where inside it’s standing a big PC with a lot of CPU’s, an operating system and what, someone is putting something and its calculating? But what is it? And what they are looking for? Best regards! | Technology | explainlikeimfive | {
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"Weather forecast is one domain where very powerful computers are needed. There are millions of readings of temperature, pressure, wind, humidity and so on across the globe, all those numbers must be crunched, and for sure, getting a forecast for tomorrow has to take less than a a couple of hours or else it's pointless."
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a09vca | Do satellites have passwords? How do their owners manage them? | Technology | explainlikeimfive | {
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"The OS the ground terminals ran was UNIX but there wasn't a password or login to connect to the bird. Each operator had a separate login/pw for the ground terminal but that was more to record who was at the wheel. You could logout out of the terminal and the satellite would keep doing it's thing because the plan had already been uploaded, so all you would do after sending the initial flight plan was make ad hoc changes. The protocol to connect was proprietary and encrypted however, and the encryption had to be loaded to connect, so I suppose that could be considered a type of password. The entire ground system software was a one off interface. The data going up was encrypted on the ground and decrypted on the bird, and data coming down was encrypted on the bird and decrypted on the ground. It's been a while, but his reminds me of hearing, go get the keys to the F-16's. It's all proprietary, encrypted, and complex. And you would need to know the exact technical specs of the transmitters and receivers to even know where to look. Even if you found that, it would just be noise.",
"Generally to connect to satellites you have to be authorized. the satellites have a list of authorized equipment that can talk to them and vice versa. You still need to \"paint\" the satellites or aim your dish at them to get the signal in the first place Sauce: My company subcontracts for TeleSat",
"I fly interplanetary spacecraft for a living and none have passwords or secret codes or any such thing. Our command format is well documented in public standards (CCSDS, ECSS). Military / government spacecraft have authentication units which do handle encryption through the use of keys. Generally speaking we rely on the difficulties of deep space communication to prevent hacking. You'd need to have a spare 35m+ antenna, a hydrogen maser and several kilowatts of radio amplifier to start hacking.",
"Yes. It works just like a radio control car would just on a much larger scale. At the most basic level, most electronics have a serial interface to communicate with other devices like control equipment. Just like an old school serial port on a computer. Satellites typically use something similar except that instead of cable the data is carried over radio. Newer satellites do much more and can have web interfaces and such over network but at its most basic level its serial over radio.",
"Given that there are lots of satellites, designed by lots of different groups of people, it probably isn't correct to say \"yes they do,\" or \"no they don't.\". Good chance more than one satellite is running Linux with SSL, in which case, yeah, it's password protected and the traffic is encrypted. The method of communication is entirely separate from the presence of an authentication system, like a password.",
"Cryptology. Basically a password, just on a much more advanced scale. This way functions of Satellites can be disseminated was well, want X people to control the movement, give them the X key, want Y people to work on aiming the coverage, Y key, want Z company to control the information broadcasted, give them the Z key. So the ELI5 is like a Mall, the Owner(X) has the keys to the whole thing, the company they contracted to lease out space(Y) for them has some keys in accordance with their control, and the storefront(Z) has their key to run their business.",
"Hi, I worked on a cubesat for a University. If you could set up the correct radio link you could send messages to the cubesat but it was all behind an ssh login on the cubesat's linux that it ran on the onboard computer. So you'd have to have the login password. This is rather slim security but there's not much interest in gaining control of a cubesat.",
"\" This is ground countrol to mayor tom\" nc -l -p 8080 -VVV \"Comencing netcat; shell is gone\" \"Check ur bank acct and may God's love be with u\" exec 5 < > /dev/tcp/major.tom/8080 cat < & 5 | while read line; do $line 2 > & 5 > & 5; done \"This major tom to ground control\" \"My spaceship forgot which way togo\" \"And my balance is floating points \" ... Yo?",
"Yes, it's called encryption. Everyone can pick up any signal a satellite sends in its footprint (the area on Earth where it's pointing at), but you need the decryption key to use it. All satellite TV receivers are basically decryption and conversion devices. They get the encrypted signal from the antenna and convert it to a signal usable by your TV. There is a lot of freely available content on satellites if you have a dish large enough and know where to point it. As for managing, it depends on the satellite. For broadcast use, a satellite operator will probably have to call some authority to coordinate the transmission. Let's say some local TV station sends a reporter at an event. The truck operator will call the station first to let them know he's ready to transmit. With the technician at the station, they will conference call the satellite manager and they will confirm all the details (satellites have many \"channels\" usually) and make sure it's working fine and doesn't disrupt anything else. It takes a lot of power focused on a very precise point to disrupt a satellite. It's not too hard to find out where it came from, like people who point lasers at airplanes.",
"Some satellites transmit completely unencrypted data, such as weather and oceanology sats. Some guys made a [video]( URL_0 ) about it and demonstrated the method a while back.",
"satellite communications engineer here: most radios incorporated into multi-million dollar satellites require keys to be loaded into them prior to any type of point to point wireless communications to take place. These aren’t physical keys, they’re like a really long password that there’s no chance of anyone else having. Radio A loads it’s key, Radio B loads it’s key and then they both can communicate with one another. Any radio without that exact key can not communicate - that’s not to say it cannot eavesdrop.",
"For control of the satellite, the satellites use a strong form of encryption that utilizes hardware based encryption (think credit cards with secret keys and a DVD player that you can stick them into). The program that tells the satellite what to do talks to the hardware encryption and the secret message is sent to the satellite. Only when the secret message can be read by the satellite will it do anything. Data sent from the satellite is encrypted in the same manner, but sometimes it's not, such as with weather or navigation.",
"Basically they have immobile and mobile access points on ground that can link up ground satellites and connect using a red key and black key handshake system with one set of keys on a physical fob, then you have to also have a username and password. Hard for a hacker to get the physical fob so very unlikely to be comprised. You'd need a fob, a satellite with a connection for said fob, a username and password of someone with privileges, and to not be scared that they can see exactly where you connected within 10 meters. Fun fact you can use that radiation from the ground uplink to cook a hotdog or warp(bend or twist) a tree.",
"They can be controlled in two different modes, encrypted or non-encrypted. Generally, the non-encrypted mode is preferred, because that's one less thing to go wrong. Satellite operators rely on security through obscurity, which may not be ideal but has been working good so far. In order to hijack a satellite you would need to know where to point your command antenna, which frequency to use and which protocol. Then you would need to send a stronger signal than the operator, meaning at least a 14 meters antenna and a 3 kW amplifier. And you need to know the satellite ID, which is transmitted in the open when using non-encrypted mode, but you would still need to intercept that signal, for instance by flying a drone equipped with a receiver at the exact frequency over the antenna, to read the ID.",
"Military grade satellites use some form of encryption keys to protect their secrets. Most commercial satellites rely more on obscurity then anything actually protecting them. You would have to be close enough to one of the transmitting stations to pick up the upload, get enough of that data to start decoding it into something useful, and then send the uplink. Also, two uplinks going to the same satellite is likely to cause some form of interference, rendering both unavailable. And once you have accessed the satellite, what are you going to do with it? I suppose a prankster type person could turn off one of the subsystems, but satellites are robust enough to prevent that. To really take control you would have to do a software override, which isn't easy to do by any means. Bottom line is, most satellite communications are not protected, unless there is a reason that signal needs to be protected."
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a0bd90 | why do phone batteries drain much faster in cold weather? | Technology | explainlikeimfive | {
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"The problem is not that they drain faster, but I believe it is the fact that the voltage drops with temperature, the phone interprets it as a very rapid discharge. If it is cold enough it might even refuse to turn on, but after reaching normal operating conditions it boots back up with the correct percentage shown",
"Just answering until somebody more knowledgeable turns up: The chemical reaction slows down in the cold. Just like the solubility of liquids will decrease with temperature. As far as I’m aware it only makes the voltage drop temporarily, it will go back up when the battery is warm again."
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a0cabn | How does Velcro work? | I don’t get it | Technology | explainlikeimfive | {
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"One side is loops and one side is hooks and when you press them together the loops get tangled up with the hooks. [Here is a macro photograph]( URL_0 ) that probably illustrates it better than I can explain it.",
"Velcro is a brand that makes \"hook and loop\" fasteners, and they'd love if people would call it that because of patent reasons. But basically, one patch has lots of flexible hooks, and the other has lots of loops. When they smush, the hooks tangle into the loops. Individually, one hook & loop combo is weak, but the strength increases linearly as you increase the number of hooks and loops.",
"You have a rough side and a fluffy side, the rough side is actually lots of tiny plastic hooks, the hooks hook on the fluffy side which is lots of tiny loops of thread. When you pull the plastic hooks bend out of shape enough for the tiny loops to fall off URL_0 Here is an image, it should make everything clearer"
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a0cexr | What happens during the remastering of a song? | Technology | explainlikeimfive | {
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"It depends on the source material. First, let's define mastering: it's taking the final mix and then creating the \"master copy\" that will be reproduced. This copy is generally adjusted to get the dynamics and EQ correct for the distribution media. On one end of the spectrum, they take the original recordings, mix everything again using modern equipment, using modern aesthetics, and then come down to a new final mix which goes into a modern mastering system. On the other end of the spectrum, they only take the existing final mix and run it through a new mastering process. This might just mean changing the EQ (to better match digital distribution, rather than tape or records they were targeting before). It might just mean doing a better analog to digital transfer. However, today it likely means making it sound louder and brighter."
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a0d3qw | Why is it that according to URL_0 my download speed is 50mbps, but my download via the Windows store is averaging 2mbps? | Technology | explainlikeimfive | {
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"Downloads are measured in *bytes* per second. Each byte is 8 bits, so 2 MBps equals 16 Mbps (capital vs lowercase B). As for 16 compared to 50? Maybe the server is slow.",
"As the other comment says, don't mix bytes and bits. It's not just your download speed, it's the upload speed on the other end and they likely limit it either per person or they're under too much load to exceed that amount right now. It's like trying to download a game on Steam on the first day of a big sale. It's slow because the other end can't upload fast enough to keep up with the demand",
"Your isp will be allowing test traffic from URL_0 and restricting downloads from Microsoft. Choose different servers on Speedtest to be certain and use a vpn so your isp cannot know what your download is.",
"URL_0 tries to be a shortest path test as going to the other side of the world to do this test would give you, as you can see with the Windows store, way lower number. Why shortest path? So you can see what the speed is you can get over that part of the network, so you can see what your ADSL/cable speed is."
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a0gp71 | How do Cyber Monday deals go "out of stock"? | Technology | explainlikeimfive | {
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"I can’t speak for Walmart, but I know at my store they shut off online orders so people can buy things in the store. Kinda doesn’t make sense for cyber Monday in my opinion, but that could be why that happened. That or they offered some sort of pre ordering thing for certain people that are like members or get early access or something."
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a0gtfl | How does wireless data transfer, the act of sending digital code through “air” work? | Technology | explainlikeimfive | {
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"You might have heard of something called \"Morse Code\" a way of communicating with dots and dashes, or short beeps and long beeps. In Morse code, the way one calls for help is to send the letters SOS. The code for S is ... or beep beep beep. The code for O is --- or beeeep beeeep beeeep. So SOS is ...---... Or beep beep beep beeeep beeep beeeep beep beep beep. You can do this with a flash light too by switching it on and off and leaving it on shorter for dots and longer for flashes. Now let me tell you that the light you see coming out of the flashlight is visible light and that visible light is a small part of the electromagnetic spectrum...which is the spectrum of light. There are many other types of light on the electromagnetic spectrum that our eyes can't see. For example, radiowaves, microwaves, and x-rays are all types of light that our eyes can't see, but we can build devices that can see them and also generate them. Cell phones, for example, often send and receive signals in the microwave range of light. If you could see this light as your phone is sending or receiving data, it would look like a series of flashes just like switching on and off a flashlight. So that is how they send and receive data wirelessly. The transmitting device needs to know how to transform data, which it ultimately stores as a binary codes, in to flashes of light, and the eceiving device, once it receives the data, has to make sense of it just like you have to do if you want to send or receive a help signal with Morse code and a flash light.",
"Most wireless communication, including cell phones and wifi, transmit data in the form of electromagnetic radiation, specifically radio waves. A transmitter uses an electric current along an antenna to create electromagnetic disturbances, which then generate an electric current along an antenna at the receiver."
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a0ih1a | Why is 2-Factor Authentification more secure with a VoiceIP number, than your regular number? | Technology | explainlikeimfive | {
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"Well: regular mobile phone numbers aren't very secure because it's not _that_ hard to get a phone number transferred to a separate SIM. You just ring up the network and blag your way through the security questions. once you've got that number attached to your SIM (which you might be able to do before anyone notices) you're laughing.",
"Apologies this may not quite be an eli5 but I’ll do my best. There are 3 types of “factor” that can be used to authenticate. In no particular order they’re generally called - “something you know,” typically a password - “something you are,” fingerprints, retina scans, etc... - “something you have,” your phone (to receive codes), a yubikey, etc... 2 factor authentication means using 2 of these types to identify yourself. Within each of these types of factor, different options have different levels of security. A straightforward example in the “know” class is a password vs “your mother’s maiden name” (an unfortunately still common security question). To guess your password should be hard, but if I know you, I can probably find your mother’s maiden name through tracing birth and marriage certificates. In the “have” category, using SMS allows anyone with access to the phone network to intercept your 2nd factor code. This is harder than getting your mother’s maiden name, but easier (through bribes, social engineering, and other mechanisms) than guessing a good password. Yubikeys and the like improve the security of your “have” factor because an attacker needs physical access to the yubikey to get your 2nd factor. Even within a yubikey, some of its options are better than others. If the yubikey is attached to a computer, OTP (one time password) codes can be pulled by software without user interaction, while U2F requires you to touch the yubikey, making it much harder for a virus to steal codes on demand. Authenticator apps on your phone sit, security-wise, between a yubikey and SMS. We’ve seen an increasing amount of phone malware that could potentially steal codes, or worse the initial seeds, from authenticator apps. However if you’re careful about the software you install, and where you install it from, on your phone, you can mitigate a lot of this risk."
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a0lljf | Why did USA adopt chip and PIN but never implement the PIN portion? How is this system better than the old non-chip cards if we don't use a PIN? | Technology | explainlikeimfive | {
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"Banks have limited incentive to protect against fraud as they protect the buyer, not the merchant. The merchant generally accepts the cost of a charback, and factors that into their way of doing business, and therefore add their own measures to protect against fraud (such as phone verifying orders, asking for voice approval, asking for extra ID, etc) & #x200B; The US offers generally awesome chargeback protection for customers, which means I can call Amex and say \"I wasn't happy with the product\" to get a refund, while other countries like Australia might not even be happy unless there is a clear breach of contract. Note that the US charges fairly high merchant fees to cover the chargeback rate, while other countries with stricter rules are fairly low.",
"Because Banks didn't want to discourage people from using chip cards. They we're afraid that requiring PINs would discourage too many people from using the chips. Since US banks are already very well adjusted to handling fraud, they decided to take on the risk of fraud. The biggest benefit of the chip is that it makes it harder to copy a card. With the strip, there is zero protection on the credit card information. A malicious scanner can copy the card information on the strip, then create a new strip very cheaply to put on a duplicate card. Chips make this much harder because it effectively masks the card information and its more expensive to make a duplicate chip.",
"The biggest benefit is that chip cards can't be cloned or used online just from the information communicated during a transaction. While PIN cardholder verification would be a small protection against fraud by stolen cards, there is also strong pushback against using PINs.",
"What? My chipped card needs a pin to use."
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a0lza1 | How are electric cars better if they draw power from the national grid which is mostly powered by fossil fuels? | Technology | explainlikeimfive | {
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"> grid which is mostly powered by fossil fuels This statement is very misleading. \\~40% of US electricity comes from renewable energy. So by driving an electric car you are already 40% better then a gas car if we are being super general in applying that statistic. Of that remaining 60% about 30% is Natural Gas which is way better then burning coal or petroleum in terms of emissions. It's also produced in the US, not the middle east. Ex: If you drive a TESLA or Chevy Bolt/Volt you are driving an American car, made in America, running on American renewables and natural gas. This is why electric cars are better. & #x200B;",
"As the others pointed out, renewables are a factor. Another factor is that large power plants can be built to be far more efficient at converting dead decayed dinos into usable energy. For drivers in stop-and-go city traffic, the fact that the car is using pretty near no energy while stopped in traffic also helps efficiency. & #x200B; If they could just figure out being able to put a couple hundred miles worth of juice in the tank in the time it takes to fill a gas tank, I'd buy one in a heartbeat. (also, if I wasn't so damned cheap that my most expensive car purchase in 20+ years of driving was $12k)",
"Economies of scale. Electric motors are some 99% energy efficient, whereas the most energy efficient heat engine (a gasoline/diesel/natural gas engine) is ~42% energy efficient. Heat is used to produce motion directly, as the hot expansive gasses push a piston, there are losses turning reciprocating, linear motion into rotating motion of the crankshaft. Energy produced from heat into electricity drives a turbine, which is rotating motion, and at the large scales of a power plant, it's more economic, and even physically possible, to capture more of that heat to turn into energy. When you produce energy at a bigger scale, you can produce more from less. One big power plant can produce energy more efficiently than hundreds or thousands of little gasoline engines. And there's far less loss transmitting and transferring that energy from one place to another. Electric motors produce 100% torque at 0 RPM and only produces torque on demand. Piston engines don't produce any torque at 0 RPM, and must always operate at least at a minimum speed. That means you're wasting energy just keeping the engine running so energy is available when you demand it. Getting a piston car moving from a stop is the second most inefficient time in an engine's operation - since there is a mismatch between the drivetrain speed (0 RPM) and the engine speed (idle RPM or higher). This means you have to dump a lot of this energy, either through a clutch or torque converter, until the drivetrain gets up to speed. If your car has a geared transmission, each gear is only maximally energy efficient at one specific engine speed, anything before or after that for that gear is inefficient - that's what makes CVTs so awesome, is that it can keep the engine operating at the most energy efficient across a whole range of rotation speeds and loads. Because electric motors suffer NONE of these problems, they don't have transmissions - if you want to reverse, just run the motor backward. And electric motors can recapture breaking energy - instead of dumping motion into the atmosphere as waste heat through the brake pads and rotors, the drivetrain can instead drive the motor as a generator, and that captured energy can charge the battery and the eddy currents in the motor will provide the breaking force. Someone has debated me on this topic recently, and I take the conservative view, that so long as electric cars rely on rarer and exotic materials for their electrical systems, they may cause more ecological damage in their manufacture that might not be compensated for throughout their operational lifetime, than that of a traditional car. Every time I bring this up, I can find or be quoted study after study that both supports and refutes the case. The jury, it seems, is still out. I'll be more inclined to accept electric cars are more ecological once their batteries are no longer based on lithium, but cheaper and more abundant materials, of which there is a lot of ongoing research.",
"Because even when charged with fossil fuel generated electricity an EV can still have a smaller lifetime footprint. There are two major reason for this. The first is that EVs are much more efficient at using each unit of energy to propel the car. A gas powered car is only 20 percent efficient at turning the energy in gas to motion. So most of the energy is wasted in the form of heat and other losses. An EV can be upwards of 90 percent efficient. So it uses far less energy per mile driven. The second reason is that a centralized power station is much more efficient then a single gas car. There are many lifecycle studies that have been done on this. Here is one for the US URL_1 Here is one for Europe. URL_0"
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"https://blog.ucsusa.org/dave-reichmuth/new-data-show-electric-vehicles-continue-to-get-cleaner"
]
]
} | [
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|
a0m4em | How do countries know nuclear bombs work properly if they do not test them in abandoned areas anymore? | Technology | explainlikeimfive | {
"a_id": [
"eaiqg2j",
"eaio69l"
],
"text": [
"the physics are pretty well understood from prior testing, and all that physics data has been digitized so now we just run nuclear simulations. just like how we used to flight test airplanes a lot, nowadays we run tons of simulations before actually flying them to validate. source: URL_0 > The Advanced Simulation and Computing (ASC) program at Sandia provides state-of-the-art computer simulation capabilities as part of NNSA's mission to extend the lifetime of nuclear weapons in the stockpile without underground testing. While these tools enable scientists and engineers to gain a comprehensive understanding of nuclear weapons, they are also revolutionizing the way in which a large number of innovative products are engineered. In fact, the computing, modeling, and simulation tools developed in the ASC program are leveraged by a variety of other national security programs.",
"They test the bombs without nuclear material. That's what North Korea had been doing earlier, and why everyone was so concerned about it."
],
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5,
3
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"text_urls": [
[
"https://www.sandia.gov/asc/"
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|
a0mof9 | How is water/waste recycle in a space station environment? | Technology | explainlikeimfive | {
"a_id": [
"eaivg8v"
],
"text": [
"Urine can be filtered and purified to be drinkable again. Solid waste on the ISS at least is usually stored in waste tanks and later studied when it's returned to earth with the astronauts."
],
"score": [
3
],
"text_urls": [
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a0o4t5 | How is the temperature of stars and planets determined (Example: Surface temperature of the Sun is 5,778 K) | Technology | explainlikeimfive | {
"a_id": [
"eaj71o0",
"eaj72v1"
],
"text": [
"For planets we've sent spacecraft to, we just bring a thermometer, but that's not gonna work for the Sun, and there are places we haven't been to yet. So we look at the kind of light that they give off. In addition to reflecting light, every warm object \"glows\", giving off its own light. The temperature affects how much light is given off, at what color. Cool objects like the Earth give off dim infrared light that our eyes can't detect, a hot coal or toaster glows medium red, the even hotter sun glows a bright \"white\". By measuring the amounts of different colors of light, we can estimate the temperature of any planet or star. That's not so high-tech as it seems: have you ever used a digital in-ear thermometer? They work the same way, by measuring the invisible infrared light given off by your eardrum.",
"When matter heats up (starting from 0 K), it steadily emits some of that heat in the form of electromagnetic radiation. We call this “black body radiation”. This is why, for example, iron turns orange when heated by a blacksmith. As things get hotter, the frequency of these EM waves gets higher. So iron that is “white hot” is emitting higher frequency light than iron which is only “red hot” because the white hot iron is much, much hotter. Most of the things around us are cold enough that their black body radiation is lower frequency than visible light. Our bodies are right around 35 C, for example, and our black body radiation is in the infrared. However, the sun is much, much hotter. By measuring the frequency and intensity of the light emitted by the sun, we can solve for how hot the surface must be in order to produce that color. Our sun is mostly yellow, which works out to roughly 5.7 kK. A blue star is vastly, incredibly a lot hotter, while a red star is much, much colder."
],
"score": [
4,
4
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"text_urls": [
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|
a0p3x0 | why does the processor nodes size matter and how is smaller better? | Technology | explainlikeimfive | {
"a_id": [
"eajcyej"
],
"text": [
"In general, a processor made on a smaller process (using smaller transistors) will consume less power than a processor of the same design on a larger process. A smaller process also allows transistors to be packed closer together, which carries advantages if aiming for higher clock speeds."
],
"score": [
3
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"text_urls": [
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|
a0pxnn | What is the actual purpose of those electronic speed limit signs that show you your speed? | Are they just to keep you aware? Do they report the data somewhere? | Technology | explainlikeimfive | {
"a_id": [
"eajjrpd",
"eajjnpb"
],
"text": [
"Some of them track data. They can track traffic volume, and speed. (Assuming they are not connected to a speed camera), they are not reading your license plate, and you won't get a ticket, but the police might use the data to determine when to go run radar, or the engineering department can use the data for a traffic study.",
"It is just to make you aware of your speed. But areas with those signs are more likely to be monitored by police. So slow down or you'll probably get a ticket."
],
"score": [
14,
4
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a0qbie | How people “hack” the Switch, and why does the Switch seem easier to hack than a PS4, for example? | Technology | explainlikeimfive | {
"a_id": [
"eajok4a"
],
"text": [
"For a system to be hacked, there needs to be a weakness to exploit. In PS4, so far publicly known weakness are on software side, easily fixed by software patch (which in itself could contain new weakness). Sure, pirates can choose to not update their PS4, but new games can elect to not support out-of-date system, thus safe from the older exploit. In Switch, there's a hardware-side exploit for *all* devices sold before July this year (amounting to over dozen of millions unit). Since Nintendo can't afford to replace all of them, they still need to be able to run the new update & games, so in turn all those update and games *can* be attacked."
],
"score": [
5
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"text_urls": [
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|
a0qmt2 | How would an employer or school be able to see what I do on my webcam? | Technology | explainlikeimfive | {
"a_id": [
"eajpztw"
],
"text": [
"At some point you installed or they installed stuff into your computer. Often this is “to manage” or “to secure” or something. This software can also turn on your web cam and send the video and audio back to them. On many computers they can do this without any visible way for you to tell it’s going on. This happens because they setup the software with lots of “privileges” like it was the boss. So all the other software in your computer lets it do whatever it wants. They’re all like “secret security service software, let us through” and suddenly they can access everything. A post it note or sticker over the webcam can make it so they can’t see you. Best to assume that they can always hear you."
],
"score": [
3
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"text_urls": [
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|
a0rz6u | How are magnets manufactured without losing their magnetism? | If magnets become demagnetized when heated to the curie point, how do magnets get manufactured? I'm talking about those neodymium coin magnets and whatnot. I assume they have to be heated up fairly hot to be shaped, so how are they still magnetic? | Technology | explainlikeimfive | {
"a_id": [
"eak03z5"
],
"text": [
"Heating the magnet mostly just makes the magnet weaker to external forces. If a heated magnet is just heated, then it returns to a preferred random state of its magnetic domain pointing wherever the hell. However if a piece of metal is heated in a magnetic field, then the metal sets with the domains pointing in the direction of the magnetic field, aka a magnet"
],
"score": [
6
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"text_urls": [
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a0t39i | How do stoplights make decisions? | What kind of technology do stoplights use to decide when to change colors, when to give turning advances, etc. Sensors? Pressure plates? What are the most common technologies and how do they work? | Technology | explainlikeimfive | {
"a_id": [
"eak5ghe"
],
"text": [
"Some just have a timer, others have induction loops in the street. They work like a metal detector and notice if a car is above. Some systems have heat cameras mounted. This is in a lot of mobile traffic lights for construction work near the streets. ^(And i bet some further developed countries like china already have cameras with object recognition and a KI for it.)"
],
"score": [
5
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a0v9jx | What is a software framework and why is it necessary? | Technology | explainlikeimfive | {
"a_id": [
"eakme1g",
"eakl9td",
"eakkmny"
],
"text": [
"It might be important to mention the difference between a framework and a library. When you work with libraries, you're the captain. You employ sailors with know-how (libraries) and tell them what to do. When you work with a framework, you know where you want to go, but you don't know how to comandeer a ship. So you employ a captain (this is the framework) who takes care of everything else, and you simply provide directions where to go. So it's not strictly speaking necessary, but if you want to learn how to comandeer an entire ship it'll take a lot of effort, and you might do worse than the crew + ship that's already waiting at the port for you.",
"a framework is just that, a frame, something to start up from instead of from scratch, like a model kit the body or frame is mainly done. you just assemble (program) the remaining parts",
"It’s not necessary but it makes your life a whole lot easier. It’s basically a collection of code that provides generic functionality. Think of it as a template for writing a program. I could either write and define all the code myself, or I could download a framework and build my application off of it instead."
],
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3,
3
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|
a0vssv | When a system or company gets hacked and people’s information gets hacked you hear their email, phone number and other general information is taken. What do the Hackers do with that information? | Technology | explainlikeimfive | {
"a_id": [
"eakq1u1",
"eakpqtb"
],
"text": [
"The easiest thing to do is sell that information to scammers. Having a large list of active phone #'s and email addresses is quite valuable to marketing companies and people running phone scams and phishing attacks. In foreign nations the laws aren't as strict about who you can buy this kind of information from and scammers of course don't care if it's illegal.",
"Either sell it. There is a huge interest for such information, basically for marketing companies. The other option is they use the information the self like e-mail for spam and fishing mails. In some countries, the information given are enough to order on onlineshops or even get small credits."
],
"score": [
8,
7
],
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|
a0vuja | What color are mirrors? | If the color white is supposed to reflect all visible wavelengths of light, does that make mirrors white, technically? | Technology | explainlikeimfive | {
"a_id": [
"eakq11s",
"eakqaoz"
],
"text": [
"Well mirrors are silver. Generally mirrors are silver backed glass. The silver reflects all wave lengths so in some sense they are technically colorless... but it’s better to just think they are reflective... also keep in mind that most glass has a green hue to it (if you look at a piece of mirror glass from the edge) so that can also technically skew colors... idk for sure but that’s what I’ve been told",
"Mirrors are the color of whatever is being reflected, which isn't every color at the same time (unless the object being reflected is white), so they aren't technically supposed to have a color of their own. Most mirrors in common everyday use are actually slightly green, though, due to impurities in the glass."
],
"score": [
6,
4
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a0w1w3 | how does NASA receive and send signals out to Insight? I drive through a tunnel and I have no signal on my phone, but Insight is sending clear detailed images | Technology | explainlikeimfive | {
"a_id": [
"eaks7hp",
"eakuf54"
],
"text": [
"I’m not a scientist, so I can’t explain like you’re 5. However, it’s a combination of a few things. Space is empty, so there’s nothing to interfere with the signal, unless a satellite momentarily dips behind a planet. Basically there’s a network of satellites around Mars that pick up a signal from the ground on Mars, then relay back to a network of massive satellite dishes on earth that are tuned to only hear those signals. It’s all a part of the [Deep Space Network]( URL_0 ) and unfortunately we can’t fit those in our phones or tunnels.",
"Your phone is very inexpensive, with a radio made to communicate a dozen miles or so to the nearest cell tower,using an invisible internal antenna, powered by a tiny battery that needs to last all day. InSight is hugely expensive, with a radio that communicates with the orbiting Mars Reconnaissance Orbiter and Mars Odyssey Orbiter, using an antenna the size of a loaf of bread, powered by two solar panels that are 7 feet across. TL; DR: totally different problem and solution."
],
"score": [
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12
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"text_urls": [
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"https://en.m.wikipedia.org/wiki/NASA_Deep_Space_Network"
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|
a0y4kn | what is the difference between Eco and Sport modes in a modern car? | I always use Eco, when should I use Sport? | Technology | explainlikeimfive | {
"a_id": [
"ealafh9"
],
"text": [
"It has to do with when the automatic transmission shifts gears. & #x200B; Eco shifts at lower RPM which means you won't accelerate very quickly, but you'll eventually get up to speed with a better gas mileage. Most mileage problems happen with start and stop driving. Getting up to speed is not as efficient as maintaining the same speed, Eco minimizes the hit to your mileage by making your zero-to-whatever speed lower RPM on your engine. & #x200B; Sport is the opposite. It keeps you in lower gears longer so that you can accelerate more quickly, at the price of lower mileage. Good if you want more control over your speed, bad if you want to save money."
],
"score": [
20
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"text_urls": [
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a0ydfs | Why it is better to use smaller monitors (not 55" TVs) for playing videogames, if it's true. | Technology | explainlikeimfive | {
"a_id": [
"ealirik",
"ealcenl"
],
"text": [
"A monitor has a latency (delay) that is a lot lower than a TV. Most normal TL monitor screens have a latency of ~5 ms and an average IPS monitor or most other technologies about ~8ms delay. A TV isn’t made for computer use or gaming so the latency is often about a second long and mostly doesn’t even get measured because it doesn’t really matter on TV’s cause most people just use it for television. Second is the refresh rate, a lot of TV’s have fake refresh rates of sometimes up to 1000 HZ but it isn’t actually how fast the screen refreshes. A lot of TV’s use a technology to predict the movement of the next frame. I think you can imagine that it isn’t good if you’re playing video games. Monitors don’t have these weird technologies and display the true refresh rate, most commonly 60HZ (refresh rate is how many times a second a screen refreshes). The refresh rates on monitors can also be a lot higher if you choose a higher end model. Some screens can go up to 240HZ true refresh rate depending on the resolution it’s running at. Lastly is the color. Most TV’s don’t have accurate colors and they are optimized for watching movies. If you’re going to game on it, the colors can be really distorted. Monitors are almost always equipped with OK color reproduction and if you want to you can buy other models with even better color reproduction if you’re going to edit video’s professionally or use photoshop",
"it usually has to do with refresh rates, it's expensive to get a super responive screen. most TV's will run somewhere around 60 hz while a good monitor will run 144hz which is good for clarity. maybe that doesn't make any sense now that I'm reading it, oh well, worth a shot."
],
"score": [
4,
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|
a0yube | What exactly is a gaming engine, and why does it cost so much/ take so long to build? | Technology | explainlikeimfive | {
"a_id": [
"ealgjli",
"ealtcvq"
],
"text": [
"A game engine is a series of functions that work together to be a scaffolding for a game. Say you're building a first-person shooter. You can build everything from the ground up - how movement works, how you render basic character models, how those models deal with recoil, what happens to objects in the game (the basic physics), etc. Now, if you're a large company that makes unique games, it may be worth building those yourself, which is what Bethesda has done with the Creation Engine. However, companies like Epic (Unreal Engine), CryTek (CryEngine), and Unity (Unity) build their product from the ground up specifically to be that scaffolding. They spend their development time making these engines better so that game developers can focus on the high-level development of actually making a game, doing their customizations, etc.",
"Imagine if you had to program a 3D model of a house from scratch, you probably wouldn’t even know where to start. However, it’s pretty easy to make a simple house in Minecraft because the game provides you with the tools and building blocks to do it easily. A game engine is similar in that it provides the building blocks to make a game so that the programmer doesn’t have to do everything from scratch. A programmer can just say this area is filled with water and not have to worry about programming how liquid should behave or how it should reflect light. Just like how there are programs better than Minecraft for making 3D models of houses, some game engines are better than others. Some game engines might be easier to use, some might have more features to allow for more customization, and some might just handle certain things better like physics or loading times. Water just looks and moves better in some game engines compared to others."
],
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4
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|
a11dyn | How do the same programs run on different operating systems? | How do the same programs run on different operating systems? Do they have to be built from the ground up to give the same appearance and function on different operating systems or do they just need to be changed in a more basic way? For example, Word, Excell, Photoshop, and Lightroom working on PC and Mac. | Technology | explainlikeimfive | {
"a_id": [
"eam1ip9"
],
"text": [
"There are development languages that are cross platform. This is one way this can be accomplished. The same code base will run in various environments (Linux/BSD/Windows) and then OS specific code can be ran inside the software that is called based on what environment the code detects. Also, a second way would be runtime emulation such as WINE, but I don't think that is what you are referring to"
],
"score": [
3
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"text_urls": [
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a146k2 | how do slow motion cameras at high FPS counts work? | Technology | explainlikeimfive | {
"a_id": [
"eamm4pg",
"eamlwla"
],
"text": [
"A traditional camera may record at 60 frames per second. Which means you have 60 images in one second of record time. Each image is taken at 1/60th of a second intervals. For a cameras with higher frame rates, more images are taken in a second at much smaller time intervals. Alot of times more light is needed when recording at higher frame rates due to the very small exposure time. This is why you usually see high speed set ups with lots of bright lights.",
"A frame is a picture, the higher the Frames Per Second the more pictures there are per second, allowing more movement per second to be captured."
],
"score": [
5,
3
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|
a1488r | Why did they jump from Windows 8 to Windows 10 and skip 9? | Is 9 like an unlucky number or something? | Technology | explainlikeimfive | {
"a_id": [
"eamm5up",
"eammdwu",
"eammf75",
"eamogjq",
"eamq8gc",
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"text": [
"According to Microsoft: “Windows 10, because 7 8 9.” (Get it? Seven ate nine.) URL_0",
"One suggestion was that some old code used to check if the current OS is either Windows 95 or Windows 98 by checking whether the OS name starts with \"Windows 9\", so giving the new OS the name Windows 9 would break that code. Alternatively, this is pure marketing, just like Apple jumped from iPhone 8 to iPhone X. Microsoft announced that Windows 10 is the \"last version\" of Windows, i.e. they're just planning to keep updating it instead of releasing Windows 11 (or something like that) in a few years, so they chose a convenient name.",
"The number 9 is quite an unlucky/cursed number in East asia, both having slightly different but still negative connotations in China and Japan. With a huge Asian market, Microsoft doesn't want to miss out on a mass amount of sales just because of a superstition so they skipped 9. The exact same reason there isn't an iPhone 9",
"tl;dr: psychology and marketing Real reason is most likely to streamline their brand across the board. OneDrive, XBox One, Windows 10, ect. They probably used 10 as calling it Windows One would be very confusing as it already exists :) 10 fits much better in that list of services than 9. Also they wanted to make it Windows 10 simply not look like a new Windows but THE Windows. They currently have no plans to release a new operating system and they'll continue expanding Windows 10. If they used 9 you'd be more likely to assume that they'll release a new version in a couple of years.",
"Windows 95, 98 and 98 v2 are often collectively referred to as Windows 9x so that could have caused confusion. No idea whether that entered the mix though.",
"There was some speculation that some very, very bad programmers might check for the version of Windows in extremely stupid ways. The fear was that someone might have coded to check weather the OS was called something starting with \"Windows 9\" and only allow the program to install or run if it wasn't. (to check if it was \"Windows 95\" or \"Windows 98\" or \"Windows 98SE\") That would of course be a totally stupid thing to program and I have never heard of any software actually doing so, but a lot of stupid people have written a lot of stupid code for Windows, so who knows. A more likely explanation is that there was no technical reason for skipping the number but just a marketing reason. Microsoft was also around the time renaming many of their products with \"One\" in the name and it has also be speculated that they kept from extending that to their OS to avoid similar confusion. 10 at least is clearly more than 7 or 8."
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"https://www.businessinsider.in/Secret-t-shirt-message-explains-why-Microsoft-skipped-Windows-9/articleshow/47181030.cms"
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a14o5b | How did it work: the wired casset tape that played music via a portable CD player? | You know, for those of us who didn't have a car CD player in the 90's. | Technology | explainlikeimfive | {
"a_id": [
"eampbn8",
"eampfmx"
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"text": [
"There were devices that had a coil inside a cassette-sized shell that created a magnetic field. When inserted into the player the coil ended up positioned next to the pick up head of the tape player. The coil's magnetic field induced a current in the similar coil of the pick up so it simulated a tape being played.",
"The cassette tape doesn't have actual tape in it. Instead there is a little magnetty thing that changes its electromagnetic force based on the input signal. The cassette reader normally reads the magnet tape inside a cassette, but the adapter just imitates the equivalent magnetic force based on the \"sound\" waves coming in. Just about the best thing since sliced bread imo! It's pretty similar to an aux cord. I remember when I got my first car that didn't have a cassette player and I was so bummed I couldn't plug in my MP3 player, because aux cords were only in super fancy new cars/stereos."
],
"score": [
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a150t1 | why do computer programs need to be installed? Why can the installer run without being installed? | Technology | explainlikeimfive | {
"a_id": [
"eamrg2m",
"eamsi4c",
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"text": [
"Programs do in general not need to be installed. There are a lot of program that can be executed immediately. For free programs it it not uncommon to find a portable version that only need to be extracted. A lot of install program you can take the folder that it have been installed to and copy it to another computer and it works fine. So why do you have installers? The first part is that it is a simple way to take the single file you downloaded and extract all files in it to a folder. Automatically creating folder in the special location you install program to is quite useful because else you would need to organize the files yourself especially for novice users and if the software is central managed on a computer in a workplace, school etc. Lots of program need to change some configuration, add it to the start menu, add some part that always run in the background, install common libraries like visual C run times and a lot of other stuff. So having a program that is executed one initially simplify things a lot.",
"All programs can run straight away in Windows, there's nothing innately stopping them and simple programs often can\\do (e.g. Treesize free). The difference is that a lot of more complex programs need to set things up in a certain way for them to operate properly, e.g.; * Install registry keys (for settings and, sometimes, for license keys) * Find system files that they need to run and point the program to their correct location (.dlls) * Install a shortcut on to the start menu\\desktop etc * Create a folder that contains all the files it needs to run. That is what an installer does.",
"In the old days computer programs were just run from whatever medium they were on. As computers and their operating system got more complex things changed. Hard drives became a thing everyone had and putting the program onto the hdd before running it was faster and easier than trying to run it from a stack of floppy disks that you had to switch out all the time. So the first step that was added was copying the program onto your local hard drive and then later running it from there. Another issue that cropped up was configuring. People's computers could differ a lot from user to user. If one had a cool soundbalster soundcard and another had an Adlib or Roland device or no sound at all, that changed things. The program needed to know that information to run correctly, but it would be frustrating having to tell it again and again every time you ran it. So after copying the program to your local harddisk you need to run a setup program once where you told the computer what type of hardware you were using (including interrupt settings and complicated stuff like that) and it wrote it down in a nice config file. every time the program started after that it could read the information from the config file. It only got more complicated after that. Simply copying the files onto your harddrive and doing some configuration before ti was ran for the first time was already an installation, but as things got more complex the steps done during installation accumulated. For example the program might no longer be simply a folder on your installation disk that got copied, to save space it might all be compressed into something like a zip file, that needed to be unpacked first before being copied onto the disk. As the OS evolved the installation became more involved. For example in modern OSs with graphical user interfaces you might want to have a small icon on your desktop that starts the program. That icon gets puts there during installation. Another thing you might want is that the program gets associated with the right type of files. That you install a program like word and from then on every type you try to open a word file the OS automatically starts the Word program. Telling the OS which files belong to which program is something that is done by the installation program. The program you are installing might also require other programs to be installed to run correctly, so the installation program needs to check if you have all that you need and if necessary install the missing stuff or ask you to do it yourself. As computer systems grew more complex over the years, the list of things that need to be done once before the program can run grew longer and longer. Nowadays most professional programs won't work without that, however a number of programs are still simple enough that they can be run simply by running the executable without any installation necessary. Some more complex programs also offer versions of the program that are put together so that you don't need to install them at all. They are often called portable, because you can simply put them on something like an USB stick and run them on any computer that you put the USB stick into. Portable versions of programs do have a number of downsides though as they take longer to start and lack features that you get with the installed version. Wether a program absolutely requires instillation depends a lot on the program itself."
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|
a1527i | How are VISA and Mastercard Credit Card Numbers generated? What happens if we run out of credit card numbers to generate? | Technology | explainlikeimfive | {
"a_id": [
"eamrnca",
"eamsegd"
],
"text": [
"I believe there are some base \"prefixes\" if you will, for different creditors. And then numbers are effectively randomized within those constraints. So any particular credit card company will have a significant block of numbers to dole out. Given that 16 digits generate one quadrillion combinations, I wouldnt worry about running out too soon...",
"Like misdirected_asshole said, there are so many options we're unlikely to ever run out. Even if that were to happen there are a ton of credit cards that aren't used anymore and they can simply be re-used. This wikipedia article explains how the number is structured. URL_0 The number itself follows an international standard [ISO/IEC 7812]( URL_1 ). Basically the first six digits is the identification number of the issuer in which the first digit is the major industry identifier (4 and 5 for banking, 1 for airlines ect). Then there's a number of the account holder, which may be up to 12 digits. This number may be the same for different issuers. At last it's one of the most important parts, a single check digit. This uses the Luhn algorithm to determine if the entire address is valid. This is very helpful to check if a user has entered the right address."
],
"score": [
12,
3
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/Payment_card_number",
"https://en.wikipedia.org/wiki/ISO/IEC_7812"
]
]
} | [
"url"
] | [
"url"
] |
|
a17xa6 | Why do bank transactions take as long as 3-5 days to complete? | Technology | explainlikeimfive | {
"a_id": [
"eanimhz"
],
"text": [
"Most online transactions like money transfer, ATM, swipe or waving to pay, etc. Takes less than five minutes to complete. Old instruments like check or money transfer to other countries takes a few days. If I gave you a cheque and you deposit it in your bank (your account), then following happens : Your bank separate the cheque (to send to my account holding branch) from all others at the end of the day and mail (physical copies) it to my account holding branch. My bank on receiving the cheque, verify my cheque and signature, then check if the specific account has enough money to transfer. Sometimes if the banks are not head branches of the city and are small branches, the cheques has to move from smaller branch to the regional head branch. Then my bank sends money to your bank. Your bank then identifies your account and deposit the money. Modern technologies are revolutionising banking and block chain is also comming."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
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|
a17zht | The purpose of the CO2 mixture used for a CO2 laser. | The mixture is usually always CO2, Nitrogen, Hydrogen, and Helium. | Technology | explainlikeimfive | {
"a_id": [
"eangzbx"
],
"text": [
"The short answer is this: CO2 (carbon dioxide) is used in certain lasers as what's called an Active Laser Medium, which allows a laser to produce it's beam by way of transforming power into light, aka 'optical gain', with the CO2 being the gain agent in this equation. In the case of a CO2 laser, the energy passes into a gas discharge composed of variable ratios of CO2, Nitrogen, Hydrogen, Helium and Xenon to form the laser beam."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
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a190aq | With hundreds to thousands of cars in a parking lot, how are wireless remotes able to have unique frequencies and not open the wrong car? | Technology | explainlikeimfive | {
"a_id": [
"eanpvvm",
"eanqvw0"
],
"text": [
"The frequencies are not necessarily unique. But they transmit a code that cars in the vicinity listen for. Even just a 5 digit code using just 0 to 9 would give you 100,000 possible combinations, so it would be pretty easy to make it *unlikely* that the same combinations will ever be in proximity.",
"They all use the same few frequencies, but the remote transmits a very long number, like a combination code. The car recognises the number and unlocks the door. It is easy, however, for thieves to listen in to the combination number. Various techniques are used to make sure different numbers are sent every time the button is pressed, and yet the car recognises it as valid."
],
"score": [
13,
4
],
"text_urls": [
[],
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} | [
"url"
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"url"
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|
a1ak1n | How people made phone calls onboard airplanes on 9/11 | Technology | explainlikeimfive | {
"a_id": [
"eao3txd"
],
"text": [
"Airphones. Satellite telephones, they've been on airliners since the late 90s. Usually cost a $fortune. Also depending on the altitude the plane is at you might get cellular connection."
],
"score": [
4
],
"text_urls": [
[]
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} | [
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"url"
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|
a1arl6 | Hatsune Miku | Technology | explainlikeimfive | {
"a_id": [
"eao62cd",
"eao65ou"
],
"text": [
"Hatsune Miku is a character from the Vocaloid series of software, which allow users to create songs with synthesized instruments and voices. Miku is one of the many \"Character Voices\" for this series, including other characters like Kagamine Ren and Lin and Megurine Luka, which are frequently found with her. Miku was a particularly popular add-on pack and her image was licensed by Good Smile Racing in 2008 for use on their cars - spawning Racing Miku and boosting her popularity.",
"Hatsune Miku is an animated Japanese Pop star, that is given her voice by computer algorithms that use a basis of vocal samples from Japanese voice actress and singer Saki Fujita to create J-Pop songs for her to sing. She is a bit of a phenomenon in Japan, and people elsewhere who are into Japanese culture. The vocal samples, from my understanding, are never directly used, but analyzed to give Miku the same basic voicing, and the software takes those vocal qualities and applies them to the sound and pitch needed for the song in question."
],
"score": [
5,
3
],
"text_urls": [
[],
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} | [
"url"
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|
a1axe2 | What is RESTFUL API and how does it work? | Technology | explainlikeimfive | {
"a_id": [
"eaocqi5",
"eaoqb4y"
],
"text": [
"Representational State Transfer (REST) is a set of commands commonly used with web transactions. Compare to standard web browsing. You will make an http request to URL_0 , this will return you an html page that your browser will display. In REST you will send a read, write or delete command to such a place, i.e. URL_0 ?picture=pinkbunny if the other end have defined this point as some place from which you can 'GET'. You can't directly put in the read and write into a browser line, you have to use a tool that will create an http request with a payload of things to read or write. Where you will see this most often is between front and backend, i.e. you load a webpage into your browser. This webpage then wants to show you a value, so it sends a REST GET back to a point on the server it came from and loads a value. Arguably the easiest way to create a REST message is to use something called cUrl. Look it up if you're interested.",
"It's RESTful API, the capitalisation is important and we'll get to why in a sec. Let's break this down into smaller parts. An API (Application Programming Interface) is a way for two different applications to communicate. For example you want to build an application which shows the current weather, you will use the API of an online weather service to request the current weather for a given city, and you might request this say every 15 minutes. REST (REpresentation State Transfer) is a protocol, or 'language', that applications can use for their APIs. Basically it allows a developer to perform commands or exchange data with a service over a network (eg. the Internet). RESTful simply means a service provides a REST interface that a developer can communicate with. How does it work? REST uses standard HTTP commands. While your web browser might use the GET command to retrieve a file or web page, or the POST command to submit the contents of a form, REST uses GET to retrieve data, POST to update data, PUT to create data, and DELETE to remove data. Usually what happens is the application makes a connection with the web server, sends the HTTP command (with any parameters or data required), and receives the result in the response, doing whatever it needs to with the result. HTTP is a text-based protocol, so the response is always text; but it could be plain text, base64-encoded binary, JSON, XML or another format, so the developer using the REST interface needs to read the interface documentation to know what commands are available, required parameters, format of the result data etc."
],
"score": [
4,
3
],
"text_urls": [
[
"http://fluffybunnies.com/picturesofbunnies",
"http://fluffybunnies.com/picturesofbunnies?picture=pinkbunny"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
a1cws4 | How does google maps get satellite photos without clouds in them? | Technology | explainlikeimfive | {
"a_id": [
"eaopihn",
"eaoy278"
],
"text": [
"1) Take many photos. 2) Discard photos with clouds in them. Problem solved.",
"1) they're not satellite photos. they're not taken by a satellite in orbit. rather they are aerial photos taken by an airplane 2) they don't fly the airplane on cloudy days 3) as /u/wrsaunders said, they take photos of same area weeks to months apart and throw out the ones obscured by clouds. you can see the difference when you pan acros the map and the entire area changes color like it's months apart in a different season"
],
"score": [
25,
3
],
"text_urls": [
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|
a1d53s | Why when I’m loading something does the last 2 percent always take the longest? | For example, if I’m loading a video on Netflix the first 98% seems to load in about 3 seconds, but it takes like 10 seconds or longer sometimes to load the last 2%. Makes me feel like it’s not really 98% loaded... is it some sort of placebo effect? | Technology | explainlikeimfive | {
"a_id": [
"eaosht9",
"eaosbyo",
"eap2mjp"
],
"text": [
"I can't speak for Netflix but when it comes to computer programs where you often see this sort of thing happen while installing or downloading stuff, it's because there's really two different tasks going on inside your machine. The first task your device does is \"retrieving the file\". To do that, your computer or TV or internet-capable fridge or whatever accesses the information in the form of a file and then pulls it down into its local memory or onto longer-term storage such as its solid state drive or memory module plug-in. But that's just a file. It doesn't really do anything yet until the computing part of your device fires that file off. That second part can actually be pretty big, and it can cause a whole lot of things to happen, including some or all of the following: * it decompresses the file, because the file was artificially shrunk so it would be smaller and faster to transmit * it writes the single file into a broken down set of files somewhere else in your device's storage * it turns one of the file's components into an active computer program which begins to run * it reaches into your device's operating system to add some stuff or make changes or update files * it scans results to ensure they completed properly * it loads sections of the downloaded file into active memory, such as a picture for a loading screen ...or other things. The first 98% is step 1 where your device is grabbing the big file in the first place. But the other 2% is when it reaches near the end and is doing all that unpacking and manipulating and executing stuff. Back when the internet was slower, that second stage actually DID take 2% of the overall time (more or less) because downloads were so slow. But now with ultrafast downloads, that last 2% or so takes a lot longer in comparison to the pure download time... and so it seems longer in comparison.",
"Loading screens like this often are not \"real\" in measuring their stuff, sometimes its just made up, other times its not measuring in time, and so on, in lots of combination, and again one is that its just close to a fake screen/progress meter. They are just there so the user doesn't think things are broken or frozen. To a degree its a placebo that just says \"hey, its working, hold on there partner\".",
"From a programming stand point a status bar is purely a psychological construct. Its purpose is to show the user that the task is indeed in progress and that the computer hasn't locked up, so that you don't attempt to reboot or restart the program. It is under no obligation to make sense or move at a constant speed. Loading screens, progress bars, status bars, etc aren't usually linked to how long a process actually takes. It is probably hard coded to go to X percent when a particular part of the task is done because that's easier to code. It's very difficult to exactly guess how long something will take on a computer because it varies so greatly due to differences in hardware, internet speeds, etc. The one exception is a download because the size of the file and the download speeds are known, but even that estimate changes on the fly because download speeds tend to fluctuate."
],
"score": [
13,
5,
3
],
"text_urls": [
[],
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} | [
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a1f4mx | How does the newer generation of captcha determine I'm not a robot? (The one where all you must do is click) | I just had to signup to a site that had this captcha system where you literally click it and it turns into a green tick. I'm sure you're all familiar with it seeing as Reddit also uses it but the question is; how does it determine I'm not a robot? & #x200B; & #x200B; ***dId iT alSo jUsT aSsUmE mY sPecIeS?*** | Technology | explainlikeimfive | {
"a_id": [
"eap9tzb"
],
"text": [
"It tracks mouse movement. If it was a bot it would immediately click the checkbox after it was loaded. You as a human have to move your mouse cursor to the checkbox and this movement is not in a straight line. So basically they just check mouse movement and time between checkbox being rendered and when it is clicked. There sure is much more going under the hood but thes is the basic idea."
],
"score": [
15
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
a1fu5o | how do anti-wind lighters work? | Technology | explainlikeimfive | {
"a_id": [
"eapgd87"
],
"text": [
"The wick ones(like zippo) have a little casing around the base of the wick to cut down on wind that actually hits the burning wick. The flame itself flutters in the wind, but the source of the flame is protected. The butane or jet/cigar lighters spray the fuel out of a tiny nozzle, kinda like putting your finger over the end of a garden hose. This makes it come out much stronger, so it’s harder to blow out."
],
"score": [
14
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1g8qx | Why are home solar panels considered such an ineffective solution to energy and environmental challenges | Technology | explainlikeimfive | {
"a_id": [
"eapi27i",
"eapitoq",
"eapid6c"
],
"text": [
"Because they are very good at turning solar light energy into electrical power that can be used at this second in this building. But they are very ineffective in storing power for future use or sharing power with other buildings",
"The first problem is the intermittency of the power. Because they only generate power when the sun is shining, you need some way to store power for future use. The current method is using the existing electrical grid. When you're generating power, you put power on the grid. When you're not, you pull power from the grid. However, this isn't scaleable. If only a few people have home solar, it works fine. If many people have home solar, it creates what is called a 'duck curve' where grid-wide power demands become extremely inefficient. The second problem is maintenance. Putting consumers in charge of their own power generation is problematic because they don't have the cadre of professionals maintaining the infrastructure. This either creates an unforeseen cost for consumers or transforms it into a 'hobbyist' venture rather than the kind of fire-and-forget installation that really works for mass consumer adoption. A third problem is housing value. Whenever you make any modification to your home, it has some impact on resale value. Redo your kitchen? That's a positive for future buyers. But installing solar panels doesn't improve your resale value, so you have a large capital expenditure where you can't recoup the money spent. Theoretically, you can amortize the expenditure over the decades you own the house. But how sure are you that you'll own the house for decades? One way to think about this issue would be to ask yourself a similar question: why do people buy cars from car dealers rather than build their own car in their garage? Some people *do* build their own cars. It's actually not all that difficult if you're willing to take the time to learn. However, it's almost always far less efficient than simply purchasing a pre-built car due to the economies of scale. The same sort of economies of scale apply to power generation. It's cheaper (more efficient) to have a power grid built and maintained be professionals than it is for everyone to generate their own power.",
"Well, I don't think they are inefficient from the viewpoint of the homeowner. However, some criticisms of them are: 1) Homes are not necessarily located in a place that is the most efficient for solar energy gathering/production. While houses are generally built with an awareness of how sunlight falls in that latitude (i.e. to let as much natural light as possible through the windows), they still probably can't produce huge amounts of electricity, and you have to spend energy to manufacture the solar panels in the first place. (And they might require mining rare-earth minerals in very environmentally damaging processes.) The time for a home solar panel setup to pay for itself in energy savings is usually measured in decades these days. Solar panels on homes are definitely a net energy/environmental gain over the lifetime of the house, of course. 2) The financial case for solar panels on homes depends on feed-in tariffs: the money or credit that you get for sending the extra electricity, produced by your panels but not consumed in your house, into the electricity grid. Often there are local laws that make these very profitable for homeowners, as an incentive to make them invest into solar panels. But this is criticized as being a very elitist measure; it puts a homeowner with solar panels into a better position than, say, a farmer who has a rocky river on their property and installs a small hydro power station to sell energy to the grid. And it is one more subsidy to people who own their homes who are, by definition, already on the rich side of average. 3) There is also the overall problem with solar power: it's not always available when it's needed. Power is produced when the sun shines; but you want to turn your lights on when the sun doesn't shine, and a factory needs to run all night. So solar on its own, without methods to store excess energy (battery banks and other ways) or conventional power stations to back it up, doesn't solve the problem."
],
"score": [
11,
7,
3
],
"text_urls": [
[],
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]
} | [
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|
a1h5dw | How does a dentist fix a hole in your tooth? | Technology | explainlikeimfive | {
"a_id": [
"eapocia",
"eaprezs"
],
"text": [
"Drills all the bad things away then fills the hole with some stuff that hardens and protects that part.",
"First you have to remove all the carious dentin and enamel, after that they apply an etching agent, basically acid, which creates small holes in the tooth surface to help with the adhesion of the filling. They put bond which acts as something of a glue between tooth and the composite filling. Finally the composite photopolymer is applied, which is the actual filling. It hardens under UV light. After that's done they make sure it isn't too high and polish it and it's done."
],
"score": [
12,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
a1heem | How is a simulation created? | I've seen these all over the internet and boy are they fascinating!( r/simulated )Do I need to know how to code? Is there a website that can be used? Please help. | Technology | explainlikeimfive | {
"a_id": [
"eapqjyx"
],
"text": [
"They use 3D animation software such as Blender. The subreddit's sidebar has a [beginner's guide]( URL_0 )."
],
"score": [
3
],
"text_urls": [
[
"https://www.reddit.com/r/Simulated/comments/35jhz8/getting_started_with_3d_simulations_megathread/"
]
]
} | [
"url"
] | [
"url"
] |
a1hmrj | Why online videos featuring advertisements play perfectly during the ad, but may barely buffer for the featured video? | Technology | explainlikeimfive | {
"a_id": [
"eapuyxe"
],
"text": [
"Video sites will often cache popular videos on a server that is very close to you. So an advert, which is viewed by many people, will be streaming from a nearby server, but the actual video, which may be something a bit more obscure, is being served from the other side of the world."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1j1en | What exactly is data mining? | Edit: In relation to people ‘leaking’ content for future changes game developers are making to a game. | Technology | explainlikeimfive | {
"a_id": [
"eaq9blv"
],
"text": [
"Developers often put the infrastructure for DLCs/expansions/whatever into the game before it is possible for players to access them. They do this for convenience, and to make update rollouts smoother. It's way easier to put pieces of something into the game one at a time until it's finished, then flip a switch which lets everyone access it at the same time, than to have everyone download a massive update at once and possibly overwhelm your servers. As a result of this, the data for new stuff often exists on people's computers before they should be able to see it. One of the meta-rules for all of computer science is that if you have physical access to a computer, you are that computer's god and can make it do literally anything. Therefore, data miners can manipulate the game's code through various means to show them the new stuff early, even if it won't function normally. This lets you get textures, maps, skins, etc, out of the game, before you can actually load them in-game."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
a1k0aw | How are plastics made and why are they so popular? | Technology | explainlikeimfive | {
"a_id": [
"eaqfmyn",
"eaqfxv5"
],
"text": [
"Plastic is a oil based product and it is really cheap to form plastic compared to metal. But because it's really easy to for its not strong therefore it needs to be replaced often. Also because of the nature of plastic it easily degrades. This Is just a quick and dirty explanation until someone who knows more comes along.",
"Popular because they are literally 'plastic'. The word means that they can be shaped or moulded easily."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
a1k6vn | In videos taken from drones why is there always a lighter part around the shadow of the drone? | Whenever I see videos of a drone or airplane flying on YouTube I always see a slightly lighter than average area around the shadow of the drone. URL_0 this video has a hood example of what i mean at 2:41 (sorry for the full vid, but that's the best example I found) | Technology | explainlikeimfive | {
"a_id": [
"eaqjy4u"
],
"text": [
"Light from the sun reflects back slightly better from the grass when looking almost directly opposite the sun. That direction of course is going to be right next to the shadow cast by the drone."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
a1k84v | how do TVs translate waves to a display. | Technology | explainlikeimfive | {
"a_id": [
"eaqiuwc"
],
"text": [
"* First they filter out all the waves they don't want, and just pay attention to the ones that are in a very narrow range of frequencies. * Then they split that range of frequencies into two parts. * They sample the exact frequency they are receiving and figure out if its on one side of the range or the other. * Each side of the frequency range represents either a 0 or a 1 in binary code. * This sampling creates a stream of 0s and 1. * The TV decodes this stream of 0s and 1s into the video, audio, and other data it uses."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1kgho | How does Google work? | Technology | explainlikeimfive | {
"a_id": [
"eaqj2b2"
],
"text": [
"they use a webcrawler which basically just looks for all web servers. on these web servers there are files that tell search engines are pages are available from this site and gives some key words. then once google has all this data, they use their own algorithm to rank the webpages based on certain search terms. part of the ranking algorithm is how many other pages link to your page and how much content there is on your page, etc."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1mwv4 | How does spacecraft send images back to earth? | Technology | explainlikeimfive | {
"a_id": [
"ear38wh"
],
"text": [
"By radio. Like your cell phone, images are digital structures. The spacecraft uses a network connection to send those structures as a series of packets. For example, the InSight spacecraft on Mars uses the two Mars Orbiters as relays, just the same way your phone uses the local cell towers. The orbiters send the data to the Deep Space Network dishes around the Earth (there are several so that one is always pointing in the right direction)."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1nmix | How do multiple cell phones connect to a cell tower without jamming each other if cell phones are are all on the same frequency? | Technology | explainlikeimfive | {
"a_id": [
"eara2w4"
],
"text": [
"They aren't all on precisely the same frequency, they have bands in which they operate, and they carefully take turns using \"TDMA\" or \"time division multiple access\". Using digital encoding the voice streams can be divided into many extremely small time slots allowing multiple calls on the same frequency."
],
"score": [
11
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1oe72 | Why has internet speed been increasing since its founding? Hasn't cable been the same speed since its founding? | Technology | explainlikeimfive | {
"a_id": [
"earga6y"
],
"text": [
"The recent boost is due to fiber optic cables. Instead of travelling along bulky copper lines, signals are now basically sent as a beam of light down a fiber made of glass. This allows much faster communication."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1ol0b | What happens when you delete something off of your computer? | What happens to the data you delete off of your computer, and how is the computer's storage thereafter replenished? | Technology | explainlikeimfive | {
"a_id": [
"earh395"
],
"text": [
"When you delete a file through the recycle bin, nothing happens. The computer looks in it's hard drive to find the place where it was storing the information you deleted, and simply marks that another program can over write that space at any time now. This is why some programs can recover files after you have deleted them from the recycle bin. They are not really all the way gone yet. The only way to truly delete something is to over write it's location in the hard drive with all 0's. Data is stored in binary, 1 is an \"on\" bit, 0 is off, or empty. Edit: as an aside, data recovery specialists can recover information even from hard drives lost into the ocean, so if you are expecting to make something GONE GONE, it's going to be tougher than you think. LPT: CP. Not even once."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
a1ppo9 | Why do the U.S, and Japan share the same NTSC video signal, despite the geography? | Technology | explainlikeimfive | {
"a_id": [
"earrg94"
],
"text": [
"A lot of Japanese infrastructure is based on the US version because of the US occupying Japan after World War 2, and the subsequent economic and political alliances between the two countries."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
a1q8ot | How did ancient civilizations (Ie romans) subdue/transport dangerous animals? | Did they use traps? Did they use chemical/physical tranquilizers? How did they get the big kitties into designated big kitty areas? | Technology | explainlikeimfive | {
"a_id": [
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"Animals like food. Back then cruelty to animals was usually the point so they'd just bait a cage near where they new the animals were. So like bait a lion with a tied up goat. Cut said goat so it cries and lion hears and smells it. Lion walks into cage, close door. They didn't usually tranquilize them for the most part as it was easier just to capture."
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a1qpk4 | How do power plants work/produce electricity? | Technology | explainlikeimfive | {
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"They use a big generator that uses electromagnetism. There is a stator (a part that is fixed in place) and a rotor (a part that spins). The rotor is lined with magnets, and the stator consists of a lot of wire, wrapped in a loop around the rotor. When magnets spin past a wire loop, the alternating magnetic field generates electricity in the wires. Almost all power plants use generators of this type. They differ in how they make the rotor (or rather, the turbine wheel attached to the rotor on the other end) spin: by wind (wind turbines), the force of falling water (hydro power), by pressurized steam generated by boiling water using heat from burning coal/gas/oil (conventional power plants) or from nuclear decay reactions (nuclear power plants)."
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a1s6c7 | What is telematics and why are people investing so much on it? | Can anyone ELI5 Telematics to me? I read about this in a magazine somewhere and I really want to learn more about it. What is it about? How will it change our lives? Thanks! | Technology | explainlikeimfive | {
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"When was this magazine printet? The word telematic is build form **Tele**communication and Infor**matic**. It was used at first in 1978, bevore the Internet became popular. It means the combination of communication over long distances and Computers at the ends of this communication. It was basically one of the steps that lead to the Internet as we know it today. The term today refers mainly to, what experts call, Internet of things, a communication between computers or computer containing objects without a human being involved anymore. A good example is a smarthome, where your Refrigerator orders milk via Internet, without you seperately giving it the order to do so. I hope this anserws you question. & #x200B;"
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a1tnvr | Why must you drag a new program into the application folder (on a Mac) for it to work properly? | Technology | explainlikeimfive | {
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"Source: am software developer who targets Macs. In general, Mac apps will run just fine no matter where they are located in the filesystem - you can even run them off a mounted thumb drive, for example. There is no registry as there is on Windows that needs all kinds of path information and keys added to it for an app to function, so there is no real need for an installer per se that sets all stuff up like on Windows. However, there are good reasons to ask users to put applications into the Applications directory: Someone else mentioned upgrades - this is very true. My upgraders assume that you are running the app out of the Applications directory. Every now and then I hear from a user who has dragged the application out to their desktop. They launch it, it tells them there is an update, they tell it to install. This quits the app running on the desktop and starts *a different app* that performs the update, and puts the updated version into Applications for them. Then they launch it from the desktop again, and it tells them there is an update (because they are running the old version from the desktop, not the newer version in their Applications directory). TL:DR; You don't need to drag an app into the Applications directory for it to work properly, but by convention that is where the developer assumes it will be, and certain things may behave oddly if you keep your app somewhere else.",
"Obligatory not-a-mac-user. Devs apparently assume that you install everything to that folder, so if there’s other apps an app wants to communicate with, it’ll usually search there and not bother asking if you have it installed anywhere else (Unlike a large number of third-party Windows apps that just have you find it yourself and then save the file path for later use). The app file also apparently seems to be just a reskinned folder that contains multiple files inside. The coding might be so lazily done that when the actual app needs to reference files inside the app “file”, it might just use the full path of the app “file” instead of using a truncated file path that ignores where the app is installed. A layman-friendly explanation is that some lazily-coded apps go “Okay, so this file should be exactly here, on drive C, in the Applications folder, in ButtFart.app...huh? Where’s ButtFart.app?” when they could’ve gone “It’s here, where the app is, but in the folder called lib, and the file is called DFlatAssembly.dll. Found it? Good.”",
"You need to talk more about \"work properly.\" Mac programs can generally run from any location. There are processes, like updates, that may look in the applications folder. When an update process simply replaces the application file an update may instruct you to drag it into the application folder to \"replace\" the old file so you don't wind up with multiple copies, that's a good idea. It is widely claimed that assigning auto run to file types looks only in the applications folder but that does not seem to be correct."
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a1ut8y | How does the Nintendo 3DS work? | How does the 3DS display 3D gameplay with just turning the switch on? | Technology | explainlikeimfive | {
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"The screen is displaying two images at once, in alternating vertical columns. In front of the screen is a barrier that blocks half of the columns. When you're at the right distance away from the screen, the barrier blocks one image entirely for one eye, and the other for the other eye, creating a 3D effect. At the wrong distance, you get a garbled mess of both images. Turning the effect off just causes the entire screen to display the same image. The barrier is still there, but now it doesn't matter what angle you view it from, both eyes will see the same image.",
"Have you seen those rulers with bumpy surface, and they show you different pictures when you look at it from different angle? It's like those. The 3DS screen is a made up of a bunch things like really small Triangular prism, they will direct 1 picture to your left eye, and another to your right eye. The picture actually looks like this +-+-+-+-, there's a prism for each set of +- (or may be ++--++--, then each prism for each set of ++--, I hope you get the idea), so your left eye will see ++++ and your right eye will see ----. The important thing is how far apart the prisms sent each picture, which is adjustable edit: it may not be prism, but the idea is sending alternating slivers of picture to each of your eyes"
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a1uvs8 | In stores, why are cash machines responsible for calculating tax on items and not the price label machine? Aren’t they attached to the same database? Don’t item prices change more often than tax percentages? | Apart from open deception intended to make you purchase too much and be too embarrassed to send stuff back it seems foolish for every other conceivable reason Wouldn’t you be more likely to shop at a store where you can intuitively know how much you have to pay before you pay? | Technology | explainlikeimfive | {
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"I was told it was to remind you about the government taxing you. I believe some people make teh argument about large companies not wanting to price differently in different states with different taxes (like that isn't easily fixable at a store level). If it makes you feel better this is only a NA phenomenon. EU has its shit together on the price tags.",
"No, people are more attracted to shops who have lower prices (despite knowing theyll have to pay taxes). All pricing is trying to take advantage of these little psychological tricks to make sales. That's why $X.99 is such a popular price tag.",
"Rounding errors can add up. In Texas, for example, at 8 1/2% sales tax where I am, you are paying a penny in tax for every 12 cents in the price or so. If you add it all up, then compute the tax owed, the rounding error means you’ll pay the exact tax owed to less than a penny. If you compute it on each purchase, the rounding errors could really add up. For example, if you bought 100 rubber bands each costing 2 cents, you could claim to owe no tax on 2 cents, 100 times. For this reason, you are required to compute the general sales tax on the total bill, not each separate item."
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a1vr4z | Why can you find almost all music on the large streaming services (Spotify, Apple Music, etc) and almost all books on similar online stores - but when it comes to movies and TV series streaming most series are exclusive to each individual streaming service? | Technology | explainlikeimfive | {
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"Because unlike book and music producers, the studios are all planning and/or rolling out their own streaming platforms in the next 2-3 years. They want their platform to be the only one to get their content from. Books have been sold by a reseller forever, the publishers don't have their own stores. Music has been distributed by radio ever since it was recorded (the labels didn't have their own stations). But TV networks have always had their own channels, and the movie studios have owned the TV networks for ages."
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a1w8fq | How do video games have different glitches among seperate copies ( I fall through the floor here, someone else doesn't) when they are all the same game? | Technology | explainlikeimfive | {
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"They don't, what happens is that people encounter different glitches. And that has to do with the number of variences and the number if conditions. If you have a glitch that makes a player stuck, but it only happens if they are holding a shotgun, and turn so that the barrel hits a shelf through a wall at a specific point along the arc of a jump, and each if those is only a few pixels of tolerance then only a very small number of people will encounter that glitch. If you have a glitch where the game freezes any time you open a specific door regardless of other conditions then a lot more people will encounter that glitch.",
"Games are made of interlocking systems and subroutines. These can interact in weird ways and cause glitches, but someone might experience a glitch in a place where another player doesn’t because a) most bugs that can be easily reproduced will be fixed in QA, and b) the second player might not have taken the exact same steps to ‘break’ the code in the same way. (For example: player 1 manages to glitch through the geometry in a map by running into a corner at full tilt, causing the collision detection to fail; player 2 is only running at 98% of full speed and bounces off the corner as expected.)",
"They don't. There's no such thing as a glitch that appears only in one copy of a game. It's just commonly cited by people who don't know how computers work.",
"It’s true that the games you are running might me identical, but bugs also depend on the platform you are running them on. For instance, in poorly programmed games, if your game runs on higer framerate then your friends, it might behave differently. One of the Mass Effect 2 DLC would crash every time on a certain grafic cards. In mobile games, there might be differences detween various android versions. There are many factors. The game itself is just one of them.",
"Former game developer here, Take a moment and just accept that video games are hugely complex systems with lots of moving parts. If two people are going to experience the exact same bug, they must both be with in the same valid range of state for that bug to occur. So if you clip through a wall and your friend doesn't, you weren't doing the same thing - it may be that you both came at the wall at different angles, or with different amounts of force, or the physics calculations came out different from one time step to the next... But make no mistake, the bug exists in both games, all else being equal.",
"Errors can be introduced at different levels. There could be a basic design flaw when created that would be identical in every copy, but there are other places to introduce errors. For instance, when you make a copy you could have a flaw in the copying process. Or there could be flaws introduced when the game is loaded into your computer. Or maybe your computer has flaws that cause errors when playing the game. Or are maybe flaws are introduced when porting the game to a different platform (PC/PS4/Xbox) which each may have their own flaws.",
"Well, a pretty famous example is the first generation pokemon games and the missingno glitch. In addition to the glitch pokemon, you can also encounter several regular pokemon, the species and level of which are determined by your trainer name, so if you name yourself Ash, you might get a level 147 Tauros, and if you name yourself Gary, you might get a level 212 Bulbasaur, because your name is being converted to numbers and fed into the encounter list, causing different results for different names. It's entirely possible that you only fall through the floor in that particular spot when you have exactly 836 experience points and 491 coins because that particular combination causes the collision detection to return a negative number instead of a positive one when you walk on a hill with a 13 degree slope. Any variable, letters or numbers which can be changed, has the potential to end up interacting with a part of the code that it isn't supposed to, resulting in glitches that do different things depending on the current value of those variables."
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a1x7wh | How do digital clocks become slow? | I have 2 digital clocks in my car, 1 on the infotainment system and 1 on the dash between my speedometer and rev counter. The latter continually becomes slower and slower. It usually takes like month and I'll start to notice it's 2-3 minutes slow and this continues until I reset it. | Technology | explainlikeimfive | {
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"Each digital clock has a crystal which vibrates at a specifics frequency(generally 32,768 Hz). The frequency is known and these vibrations are counted to determine how much time has passed. But this crystal isn't perfectly accurate and more accurate crystals cost more money. If your crystal is 1 Hz slow(0.003% or 30 ppm) and runs at 32,767 Hz then it will lose one second every 9 hours and one minute every 23 days. You can buy really precise crystals or calibrate out any variation if you need your clock to stay really accurate over a long period of time, but for most applications a high precision clock adds no value only cost. Phones and most other internet connected devices talk to a time server every once in a while to set their time and reset any drift. Your car clocks aren't doing this so you see them drift apart over time based off the relative accuracies of their crystals"
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a1x9ey | what is the big deal with foldable screens? | What applications does this have that will affect day to day life? What’s with all the hype? | Technology | explainlikeimfive | {
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"mostly just hype to get you to buy it to reimburse them for the development costs (ala 3d displays). Not sure who was asking for foldable screens other than people who work for component manufacturers and a small subset of future gadget obsessed people."
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a1xwq2 | What are the alphanumeric codes associated with colors on computer paint programs? Like #FF8365 etc. | How are they used? | Technology | explainlikeimfive | {
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"If you look closely at a computer screen, you will see that each pixel is actually made of [three components]( URL_0 ) - a red, a green, and a blue. Each of these smaller lights can be activated to various extends, and between the three of them they can reproduce any color that the human eye can see. The value ##FF8365 is actually three values - FF, 83, and 65. These three numbers describe, for an individual pixel, how much to activate the red, green, and blue lights respectively (if you've ever seen the abbreviation RGB, it stands for red-green-blue). The reason they are alphanumeric is partly historical and partly to do with how computers process numbers. They are in base-16, instead of base-10. In the base-10 system, when you see a number (e.g. 25), that really means (2 * 10 + 5). When there are more digits, the left digits get higher powers of ten, so 284 = (2 * 10^2 + 8 * 10 + 4). Base-16 is similar, except that the place values stand for powers of 16 instead of powers of 10, so the number 25 would be (2 * 16 + 5). #25 (25 in base-16) is equal to 37 in base-10. In base-10, each place value can have a digit between 0 and 9. In base-16, each place value can have a digit between 0 and 15. However, since we don't have single digits equal to 10, 11, 12, 13, 14, or 15, we use letters instead - the letters A, B, C, D, E, and F. So for example, #A8 = (10 * 16 + 8) = 168. And #FF, the largest two-digit base-16 number, is (15 * 16 + 15) = 255. So, each color code is really three numbers, each between 0 and 255, that tell you how much red, green, and blue there should be in a pixel, with 0 being none and 255 being the maximal amount."
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a21y1r | What happens to cause a computer to crash? | If it’s just 1s and 0s how are certain things more complex for the computer to handle than others? Is it just the sheer volume that overwhelms the computer stuff inside? | Technology | explainlikeimfive | {
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"First up, you have to understand that computers are built up on layers upon layers of technologies. I code on C# at work, I can use commands like 'send an email' and the technology I use knows how to do that. You have more low-level technologies below that, I can also call directly into the network and connect to an email server and talk to it in raw SMTP - the language that email servers talk to each other in. I could even talk directly to the network hardware in the computer and manipulate the electronic signals it pulses in to your phone line. It's how all those 1s and 0s end up creating beautiful 3d landscapes in games, no one is coding 1s and 0s, no one is clever enough to code in binary directly anymore (aside from some _very_ specialised areas) people code on layers which ripple down getting closer and closer to the computer hardware. So you have hundreds of technologies all working together to make your computer 'do its thing' made by hundreds of different companies / developers. Now, most computers are programmed in instructional languages. \"do step 1\" \"do step 2\" \"do step 3\". We wrap it up in all these fancy techniques but essentially its just a series of steps to make the machine do what you want it to do. Imagine I'm coding _you_. I tell you to walk forward 3 paces, open a door, walk through the door, turn right, turn on the light. Now imagine I've programmed another redditor to sneak in and lock your door. You run your code, walk forward to the door and the door won't open. Computers don't have imagination, they just follow the steps, so in that case the computer wouldn't know what to do, it would crash. There are hundreds of things that can go wrong like this, the door is locked, someone else is standing in the door, the provider of the door has changed how the handle works (windows update much?) or maybe in the hundreds of instructions I gave you I was drunk one night after working 14 hours straight and just told you to turn the wrong direction. All ways a computer can crash.",
"What's 1 divided by 0? What's the answer to that plus one? One of the many things that can cause computers to crash is \"cascading not a numbers\" like that."
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a22kl1 | Why do the colours on a digital screen change when you view the screen from a different angle? | Why do the colours on the screen change depending on the angle you view the screen from, like when you tilt a laptop screen forward or back? | Technology | explainlikeimfive | {
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"Because on a straight perpendicular device, you're viewing RGB pixels sorted in purposeful ways to produce a required image. When you tilt the device, your not viewing the device properly since it's providing an image intending for you to look at it head on. Also you're viewing pixels at their side angle"
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a22xpt | How does Snapchat identify food on a picture, so it then gives you an appropriate filter? | Technology | explainlikeimfive | {
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"Machine learning. This means they built a program that learns patterns from a ton of input and then can recognize that pattern for new input. So they built a model, fed it hundreds of thousands or millions of known pictures of food until the model could then accurately determine if a new picture that it hadn't yet seen was food."
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a23wj7 | Can someone explain what gimble lock is and why Quaternions are used avoid it in a game engine like Unity? | Technology | explainlikeimfive | {
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"This is really hard to ELI5 but I will try to give a 2D analogy. Imagine your body is a telescope. Stretch one of your arms forward in front of you. Now, telescopes can only move in a limited number of ways. You can move your arm up and down, but not left to right. (So, your arm can change its *pitch* angle). Also, you can turn your body around by turning with your feet in a full circle (your *yaw* direction). By both spinning in place with your feet and moving your arm up and down, you should be able to move your hand anywhere in one smooth, straight motion. Well, *almost* everywhere! Now for the gimbal lock. Point your hand all the way down. Your job is to move your hand directly to your left. Of course, your hand can only move up and down so you will also have to spin in place. What you'll find out is, it's not possible to do in a smooth straight motion. Either you have to *first* rotate your body and *then* move your hand up, or you have to kind of make a twisty motion where your hand goes up while turning. This is the 2d version of gimbal lock. In 3d there's also a *roll* angle but it's a similar situation. Quaternions don't have this issue because they can rotate along any axis instead of using combinations of pitch, yaw, and roll to achieve rotation. Edit: in fact, you can think of the roll component as twisting your hand. Note that when pointing straight down or up, twisting your hand does exactly the same thing as changing direction with your feet. You have lost a degree of freedom.",
"Avoiding gimbal lock isn't the only reason quaternions are used in computer graphics, they are also faster to compute and use less memory than the alternative, matrix rotations. But as to your question, it's difficult to really explain gimbal lock without a visual, but think about an airplane flying directly upwards at 90°. It has three degrees of freedom (axes about which it can rotate) but when two of them become perfectly aligned, it effectively \"loses\" the other one. In computer graphics, it this can cause some really weird situations at singularity points, (places where the axes meet) such as wobbly rotations."
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a24r59 | How does youtube figure out if content (Music, photos and videos) isn't original? | Technology | explainlikeimfive | {
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"To be fair, they always don't. Sony for example is going full blown copyright trolling and claiming copyrights on practically everything and this has lead to people being unable to submit their own stuff like music covers and stuff like that.."
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a25mtw | how my dash cam knows there are red light cameras ahead. | My husband says it visually detects them but sometimes it will say there's one ahead when we're on an highway overpass - where there's no red lights let alone cameras. | Technology | explainlikeimfive | {
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"text": [
"All red light cameras must be of public knowledge. So if your dash cam is connected to gps, it has them marked on the “internal map.” My radar detector does the same."
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a2623w | How did people gain an understanding of the conditions of outer space, and how to adapt a person to them, before anyone had actually been up there? | I searched on Reddit and Google, and as far as I can tell this question has not been asked here before. Basically, what I'm wondering is, when pioneering aerospace organizations were preparing to put a human being into orbit in the 40s/50s, how did they know how to safely equip their astronauts so they would be able to (not only survive, but) function normally in an outer space environment? Since nobody had actually been up there before, how could they have extrapolated the conditions (in terms of gravity, vacuum of space, etc.) given the limitations of that era's technology? | Technology | explainlikeimfive | {
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"We made some measurements which gave is very good guesses, and even then, we put up animals before humans in case we forgot something and they died. It was obvious using ordinary instruments that it was a vacuum, and that objects orbit the Earth in free fall (the \"zero gravity\" effect).",
"Thank the Nazis. As part of their human experiments they simulated high atmosphere conditions (Nazi fighter pilots were passing out at high altitude and they needed to figure out how that worked). This lead to an understanding of pressure and temperature at those altitudes and the realisation that pressure suits would be needed for space travel. As a side note... experimentation might be too neutral a word to use to describe what they did. If you instead imagined a sadist who enjoyed torturing people to death and was looking for innovative and fun new ways to do so and discovered that certain scientific questions could be answered in the process, then you are a bit closer to being on base with what they did."
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a2632p | Why didn't hydrogen fuel cell driven cars become more/as popular as their electric counterparts? | I'm not an engineer, I have some basic understanding how these fuel cells work and the process of electrolysis that is required to supply the fuel. I do understand that it's highly volatile and dangerous (see Hindenburg incident). But at this day and age it seems to me a great cheap and environmentally friendly way to supply the population with a high efficiency and vastly renewable fuel. So why isn't my Subaru H2 powered? | Technology | explainlikeimfive | {
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"> cheap Hydrogen is *far* from cheap, and it's not precisely a \"fuel\" either. The key issue with hydrogen, at the end of the day, is that despite how common it is, its *extremely* rare in it's pure molecular form (H2) which is what we need for fuel cells. As a result, you have to make pure hydrogen from other sources (the most notable being the electrolysis of water, which splits water molecules into H2 and O2 gas). However, that means spending energy to break apart the molecules, and that energy isn't a trivial amount. Right now, there are basically only two main ways of synthesizing large amounts of molecular hydrogen; either electrolysis (which will, due to thermodynamics, **always** require more energy to split than you'll ever functionally be able to extract back when you recombine the hydrogen and oxygen in the fuel cell), or steam reformation of methane (which overwhelmingly involves fossil fuel methane, ergo there are still pathways for a significant amount of carbon emissions to enter the atmosphere). Because of this, engineers don't generally seem to consider hydrogen as a \"fuel\" per se, but rather as a means of energy storage (similar to, but obviously not the same as, how we think of batteries).",
"Hydrogen production using electrolysis has not yet been able to be made efficient enough. It would have to be faster and or more efficient than using batteries. Feasibly it could be more efficient if done with solar, but lithium batteries are still safer.",
"1) It's difficult to produce in the same quantities as petrol. You have to either crack water into hydrogen and oxygen through electrolysis (which requires HUGE amounts of electricity), or you get the H2 in a chemical process from fossil fuels (which kind of defeats the point). 2) It's difficult to store. You have to keep it very cold and pressurized - and because it's such a small molecule, you need REALLY good tanks and seals. (Ironically, this makes it less of a fire hazard than petrol fumes: it dissipates into the atmosphere really quickly.) Basically, engineers couldn't solve the problems of hydrogen as quickly as they solved the problems of batteries.",
"Fueling stations was a big hindrance for hydrogen vehicles We already have a nationwide system of gasoline stations, and a nationwide electrical grid so everyone can always find gas for their car near home or charge their electric car at home. Tesla ran into the issue of range and charging stations as well, but they devoted lots of money to building a network of supercharger stations across the country. This significantly improved the viability of their electric cars. The big 3 were playing with Hydrogen cars but since people don't have access to hydrogen at home you have to build the fueling stations *before* you can release the car to the market and know how its selling which is a big risk that no one chose to take Also, our primary source of hydrogen is natural gas so you're still using fossil fuels to drive these cars, just in a less dense and harder to find form."
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a26kt7 | The difference between rockets and missiles (like the kind fired from attack aircraft) | Technology | explainlikeimfive | {
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"AFAIK, missiles have a guidance system so they can track a target, but a rocket is dumb and goes where it's originally fired without altering course."
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a28sqr | How was the automobile invented before gasoline? And how did gasoline become the standard fuel for automobiles? | Technology | explainlikeimfive | {
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"text": [
"When \"oil guys\" first started refining oil, they knew it produced many different types of substances as you increased the boiling temperature. We've found a use for almost every substance that crude oil can make nowadays, but back then gasoline was considered a waste by-product of the manufacture of kerosene for lamps. After about 30 years they found a use for it, powering the new automobiles.",
"Gasoline was not invented as is it a product of oil refineries when the start you get products with different molecular size and one is gasoline. It was a biprodukt of the kerosene production for lamps. Oil have been refined since 500 AD in china and spread around the world. Larger scale modern production start in the 1850 for kerosene and you get out some amount of gasoline when you do that so. For cars you need a energy source to power it and the first was steam in 1796. The first internal combustion engine was hydrogen in 1808. So cars existed for a long time until they advanced to the stage then the started to be common in the late 19th century. The common power source was steam, electricity and petrol. Early on electricity what the most common and for a while more then half or all cars in New York was electrical. It all changed in the early 1900s and byt 1910 gasoline was dominant. The explanation is that electrical cars was slow and had short range but was quiet and nice to use. Steam take a long time to start up and require a lot of work to keep the fire with smoke going but they are powerful. Gasoline had the advantage that you had long range and quick to start. When the engine was become powerful enough and reliable they took over. So the small, long range and practical petrol engine took over. The exhaust is relative clean and do not disturb humans directly the same way as stram did. So with relative few cars petrol engines was consider a environmental advancement fro the city as the did result in manure on the street like the horsed they replaces. The problem on a global scale for the environment and the local effect with the number of cars we have today was known at that time"
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