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Since the human body is widely influenced by ion channels in the cell, does magnetism affect this at all? Would prolonged exposure to magnetism have any effect on one's health? | Well, the strength of MRI ( Magnetic Resonance Imaging ) is limited by their ability ( when strong enough ) to stimulate nerves via this principle. They operate just at the stimulation limit. It is not uncommon for patients having a MRI to experience facial tics or muscle twitches due to this.
It is theoretically possible that if the magnetic flux were increased, that a MRI machine could cause serious problems, such as heart arrythmia, breathing problems, etc.
Mind, this is "Acute" exposure to incredibly strong fields. | 17 | 32 |
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Why when I tilt a cup to slowly pour liquid out, does the liquid not fall straight down but seems to grab and runs down the outside of the cup instead? | I presume it's got to do with path of least resistance and the liquid itself is holding some sort of resistance...but I'm sure some high school physics would explain this better. | It is a combination of surface tension and van der waals forces. Surface tensions keeps small drops of water in a spherical shape and van der waals forces will gently make it adhere to most surfaces. These forces are relatively weak and not very noticeable on large scales.
Edit: It's a combination of hydrogen bonds and VDW forces and surface tension is a product of this. | 297 | 576 |
ELI5:how do we determine how good an animal’s eyesight is? And how do we compare it to our own or another animals? | There are a variety of studies that can be done. Some are observational. You see an eagle swoop down from one thousand feet high to catch prey and you have to assume it was able to visually detect the prey from that distance. Lab tests can be run in a similar fashion, putting something desirable at various distances away and recording how far or close the animal has to be to notice it.
You can also learn stuff by analyzing the eye itself via dissection. Like humans, other animals have rods and cones in their retinas, and scientists can observe the density and types of these structures to get an understanding of what types of light an animal might be able to detect and how well. For example, nocturnal animals will typically have more rods and fewer cones to adapt to low-light vision. Meanwhile, the aforementioned eagle's eyes have a larger variety of cones compared to humans, indicating that they see differences of color much more precisely than humans which helps detect prey at long distances. | 42 | 91 |
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What is it that is keeping us from having "wireless" electricity? | There are ways to charge certain small electronics via inductive charging, but why haven't we gone "completely wireless," to the point where we even need to plug things in anymore? What's the roadblock, and when will it conceivably be overcome? | Electromagnetic waves spread throughout space and weaken with increasing distance from the source. A wireless signal can be weak as long as it is amplified upon being received. If you want to send a large amount of energy, and not just information, then you're stuck. Even most information today is actually sent by wired signal through fiber optic cables. | 13 | 25 |
ELI5: What's the difference between an Embassy and a Consulate? | Its kind of like a library system, you have the main big library in your area and the smaller branches depending on it.
In simple terms the embassy is the main headquarters, where the ambassador lives there can only be one ambassador from a country so therefore only one embassy.
Consulates are offices of the embassy spread out in bigger cities so you dont have to travel to the embassy, they provide the same services but slower at the Consulates because they usually send or forward the paperwork to the embassy. | 28 | 30 |
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What do scientists mean when they say "We only know what makes up 5% of the Universe"? What makes up the other 95% of the Universe and how come we don't know what it is ? | We can measure the total matter density.
We can also observe how many stars there are and what their masses are (and calculate the energy corresponding to this mass). They contribute 1% to the total energy density. Add gas in galaxies, gas between galaxies, planets, black holes, and everything else we can directly observe and you end up with about 20% of the total matter density.
What about the rest? We know it is there from its gravitational influence, we can even map its density, but we don't know which particles it is made out of (there are searches for possible particles, but without a discovery so far). This is dark matter, contributing about 80% of the total matter density.
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We can measure the expansion rate of space, and the total matter density allows to calculate how much expansion should slow down over time. But the measurements show it is expanding. There are multiple ways to describe this, but the easiest approach is dark energy: A constant energy density everywhere that - unlike matter - makes the universe expand faster. To compare this to the matter density, we can convert the matter density to an energy density via E=mc^(2). The overall result is 68% dark energy, 27% dark matter and 5% regular matter. | 59 | 93 |
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ELI5: Why do male shirts and female blouses have their buttons lined up on opposite sides? | Historically women were more likely to have maids and such doing most of their dressing for them and it was easier for the servants to button the clothing if the buttons were on the opposite side. Most people being right handed and all that. Tradition carries on.
Edited: missed a word or two | 91 | 43 |
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Why are there only two genders in nature? Why not more? | First, a semantic issue. Gender is a cultural term, and some cultures do have more than two genders.
Sexes are the scientific term, of which humans have two, barring exceptions.
As the animal kingdom comes from a common ancestor, two sexes is generally common. However, there are some species which have individuals that reproduce asexually, are hermaphrodites, can change their sex, or are sterile. You may consider this just different variations of the two sexes, which is appropriate.
When you move away from the animal kingdom though, you can find more "sexes" in bacteria and fungi. A conjugative plasmid separates bacteria into F positive and F negative for that plasmid, and there are more than one such plasmids a bacteria can or cannot have.
Some Fungi have mating types that are noted as + or -, which are already different from male and female. Some fungi take this a step further and have even more mating types. These mating types are there to prevent a fungi from sexual reproduction with its own mating type. | 34 | 31 |
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ELI5: What is the purpose of the 'Press Start" screen at the beginning of almost every video game? | It has two purposes, one modern and one more historically.
Right now the main reason of the start screen is to identify the player (in case of more than one controller connected). The player is the one that presses the start key. It also gives an opportunity to ask which storage device should be used.
The second reason is that console manufacturers require the player to have an input before a certain time frame has passed. This to ensure that the game is being started properly. The press start screen is a perfect opportunity to do this since it doesn't require many resources to be loaded yet. | 419 | 750 |
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ELI5: Talking on radio transmitter at 50% speed of light. | What would it sound like if I am traveling at 50-90% the speed of light and communicated to a stationary person via a radio transmitter? Would my voice be slow? | There are two things that are going to have an effect here.
1) Doppler effect (which depends on the relative locations of you and the stationary observer)
2) Relativistic effects (time dilation primarily)
In any case, the effects will likely result in the fact that the radio reciever won't even recognize your signals, unless it's designed to account for that. | 13 | 37 |
Curious to hear economists' breakdown of Einstein's "Why Socialism?" | There's this [article](https://monthlyreview.org/2009/05/01/why-socialism/) by Einstein blatantly endorsing socialism.
I'd like to clarify that I have no dog in this fight, and I think Einstein being Einstein deserves the benefit of the doubt.
Now I read the article. It has some interesting points. Though it seems very idealistic in some cases.
Most discussions I've encountered about this article online and on reddit talk about whether Einstein's qualified to talk about this along with the typical socialism/capitalism circlejerks.
None are actually addressing the points being made in the article.
So I'm curious to hear what economists have to say about the things written there. | You should keep in mind that Einstein, while an excellent physicist, is about as educated in economics as your average Joe, and not instantly credible in the field of economics because he's good at physics. Same goes for an economist regarding physics. If an economist wrote a paper on general relativity with a bit more than average research (that probably isn't correct to begin with), would you take him seriously? Probably not.
In the article, he seems to be essentially saying that economics is not a real science by comparing it to astronomy, which isn't a very good argument. The field of economics does have a set methodology they use to conduct research. See Econ methodology FAQ in the sidebar of this sub.
He then appears to make the ethical argument for socialism, which, while completely ok, is outside the scope of economics.
Overall this article isn't much different from any other. It ignores basic economic concepts and instead makes an ethical case, which an economist can't really respond to. | 195 | 140 |
How do trees fight off disease? | I'm assuming trees don't have an immune system, so do they have any protection against disease? | Trees *do* in fact have an immune system, as all plants do! Plant immunity is an innate immune system, while animals have innate and adaptive immune systems.
Plant immunity is, in general terms, concerned with detecting pathogenic proteins and/or pathogen-associated molecular patterns that would signal the presence of a potential plant pathogen.
Once detected, plants activate a number of processes designed to make the plant tissue inhospitable for a plant pathogen. A classic hallmark of plant immunity is the production of reactive oxygen species (or ROS) that will kill pathogens or drive them to dormancy. This is analogous to a fever in animals.
Another molecular response that occurs in plant immunity is the creation of barriers to the diffusion of pathogens. Deposition of callose - a complex polymer - prevents pathogens from growing or moving freely in the interleaf space. In more serious immune reactions, plant cells around the pathogen will kill themselves in a process known as the hypersensitive response (HR). This denies the pathogen living tissues and nutrients.
Another important barrier that prevents plants getting sick is physical barriers. The bark of a tree is an excellent barrier, much as our skin is, to prevent pathogens from getting anywhere near the important parts of the tree. This is why the vast majority of tree diseases are seen after the tree is damaged by pruning, weather, or by burrowing insects. | 64 | 43 |
Eli5: how does alcoholism run in a family? | I under stand cancer and diabetes but if alcohol is an out of body deal how it is it possible for it to be genetically in a family? | Biochemist here--Our genes code for proteins that impact many things that can relate to alcohol addiction, including how our body metabolizes (breaks down) alcohol, and how our brain responds to it.
In particular, some people inherit DNA that makes them have a higher liklihood for their brains to enjoy alcohol and to become biochemically dependent on it. This can also occur for other substances too, even cigarettes.
There can also be other traits and conditions that someone can inherit from their parents that can make them more prone to alcohol misuse, such as biopolar disorder and ADHD.
edit: The expression of these genes can be affected by environmental conditions as well, so it can get very complicated. | 59 | 28 |
ELI5: What more megapixels give you and what they do not (or, why more megapixels isn't necessarily "better") | More megapixels means that you get images with more pixels. This means you can make a larger image at a given resolution, or have better resolution for a given size. Most people don't make prints large enough for this to really matter, as most cameras have plenty of megapixels.
More megapixels can be bad when you have to cram a bunch of them onto the camera's sensor. This is a silicon chip that detects the light and makes the image. If you try to squeeze in a bunch, you can limit the quality of the pixels. For a point and shoot camera, it doesn't make sense to try to put in more than 12megapixels or so, because the camera's sensor is quite small.
A fancy DSLR will use a bigger sensor, some as big as 35mm film. There are many reasons this can be better. One of them is that you can increase the number of megapixels without degrading the quality of the sensor. There are also optical advantages that allow for higher resolution.
None of this really matters, though. There are other factors that are far more important than megapixels, like lens quality and skill. Learning what sort of light is good for shooting or how to use fill flash will both get you better images than any number of megapixels. | 11 | 15 |
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ELI5: What happens when your injected with blood of a incompatible type? | You must first understand how bloodworks:
Type a blood has an "A" antigen(basically a license plate for your cells to tell your immune system what they do)
Type B blood only has a "B" antigen
Type AB has both an "A" and a "B" antigen
Type O has none of these antigens
So your immune system is good at attacking anything that it doesn't see as normal. It is afraid of change so it will kill bacteria and stuff but also any foreign cells. So your immune system uses the antigens to see if the blood is the same type as it. If you have type O(no antigens) but your immune system sees a type A blood cell then it will pour all its resources into getting rid of the type A blood cells and you will get sick from your immune system not being able to do more important things.
Now let's talk about donations: if you have type O blood then you can donate your blood to anybody(no matter the blood type of the recipient ) and type O people are known as universal donors for this. They can donate to anybody because their blood has no antigens and thus can't be recognized as foreign to the immune system(it's a bit like taking off your license plate because the police can't identify you). If you have type AB blood you are a universal recipient because you have both A and B antigens so your body won't attack the blood because it thinks it's natural.
I hope that helped
Source:I am in a college Hematology class. | 26 | 27 |
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eli5: How can Google maps know many small and recent businesses' locations so accurately? | I've realised that most businesses (even small kiosks) are seen on Google maps. Where and how do they get that information? | These days most businesses enter themselves into google maps. It's really simple and it drives traffic to the store.
Back in the day, these kinds of things were community sourced. If you turn on the option, even today google maps will ask you a bunch of questions about places that you've been. | 3,673 | 2,963 |
Does non-Euclidean geometry render Kant's claim that space and time are a priori intuitions irrelevant? | What the title says.
Per my understanding, Kant claims that space and time are a priori intuitions, but the discovery/ potential of non-euclidean geometries means that to find which one is 'right', we must test them against each other, making our intuitions of space and time empirical.
Please correct me if I am wrong. | The typical argument is that post-Kantian developments on this point require us to distinguish intuitive, mathematical, and physical spaces in a way that Kant didn't--or rather, to regard them as independent in a way that Kant didn't. For Kant, these three concepts are interconnected in an important way: our intuition of space serves as the ground for our judgments of geometry, and this relation between intuited space and geometric space explains why objects of intuition are describable by geometry, so that it serves as the ground for physical space.
The subsequent developments in mathematics led to the idea that we can speak of a number of diverse geometries. The implication here is not that geometric space is an empirical rather than a priori intuition, but rather that it's conceptual rather than intuited.
This mathematical development raised a new question about what geometry to use in the theories of physics. As you say, on the typical view this choice is responsive to experimental considerations, but that doesn't quite mean physical space is an empirical intuition. If the theories of physics are admitted to be conceptual constructions, then they are freed to use whichever geometry best suits the requirements of their theorization, and it could be that physics settles upon a construction of space distinct from our intuitive experience of space. | 17 | 57 |
ELI5: Why do taxes get taken out of your paycheck, but then you get taxed again when you go to buy food at Burger King? | There are a lot of different laws written that include a lot of different taxes - where they are applied, and what those funds go towards. So, you might pay 10 cents a gallon in tax on gasoline to fund highway repair, and 6% on soda towards the general state government, and some amount of taxes based on your income to the federal government. | 42 | 68 |
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Eli5: Why is Prince Philip of England a prince and not king, despite his being married to the Queen? The wife of the previous king, George VI, was Queen Elizabeth, not Princess Elizabeth. | The fact that people are upvoting this makes me feel glad that I wasn't the only one confused by this!
Mandatory "This blew up" edit.
Marked as Explained, because of /u/barc0de's fantastic explanation. | There are two types of Queens, Queen Regnant and Queen Consort.
Queen Regnant inherits the position from the previous monarch, and is the ruling head of state
Queen Consort is the wife of the current monarch and has no official role within the state.
There is no equivalent King Consort, so Philip could only be Prince Consort instead. Ruling Queens have avoided naming their partner as King to avoid appearing weaker or not in charge.
The only occasion where a Queen Regnants husband was styled King was as a result of the glorious revolution when Mary replaced her deposed father on condition that her husband be allowed to rule jointly with her | 4,473 | 4,583 |
CMV: The Bible does not clearly explain the requirements for Christian salvation | Apologies in advance for my hungover brain not forming very good sentences at the moment.
I had a conversation on [this](http://www.reddit.com/r/changemyview/comments/2qf2pw/cmv_if_a_religious_person_truly_believed_their/) thread that made me realize this could be a good CMV.
In mainstream protestant Christianity, the idea that salvation is gained through faith alone is an important tenet. It is supported with passages like these, mostly from Paul's letters:
>If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved. - Romans 10:9
> For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast. - Ephesians 2:8-9
But other parts of scripture seem to paint a different picture. [This long-ass passage](https://www.biblegateway.com/passage/?search=James+2%3A14-25&version=NIV) from James, and [this longer one](https://www.biblegateway.com/passage/?search=matthew+25%3A31-46&version=NIV) from Matthew make a pretty strong case that salvation requires doing good deeds.
Anyway, I'm not a believer anymore, but I'd like to hear some compelling arguments that Christianity *is* actually crystal clear on what it takes to achieve salvation.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Some argue that the Bible is quite clear on this point--that true faith inevitably results in good works.
Ephesians 2:10 New International Version (NIV)
10 For we are God’s handiwork, created in Christ Jesus to do good works, which God prepared in advance for us to do.
This, according to those who argue in this vein, explains the other passages. For example, in the Matthew and James passages you quote, the argument is that a person of true faith would never allow a man to starve or turn the needy away from his doorstep. However, even if you did good works in the absence of faith, lacking faith would mean that you had never received the gift of salvation through Christ from God. | 11 | 24 |
ELI5: Why doesn't the metal walls of the microwave cause sparks but most every other metal does? | Obligatory front page edit!! Thanks for the answers guys/gals! | First off, the problem that metal in a microwave causes most often is that the metal can reflect and focus microwaves into food or onto the walls, causing things to burn or melting the walls. The worst thing that can happen is the metal reflects the energy right back into where they came from, damaging the Magnetron, the thing that makes the microwaves that cook your food. The walls of the microwave do the same thing, but are designed to evenly reflect the microwaves around the microwave without reflecting them back into the magnetron. The reason you might see sparks when you place a metal object in a microwave is that metal will naturally pick up a static charge when hit with lots of energy. When this happens in a microwave, it happens with enough energy and for long enough to see the static charge overcome gaps between one area of the metal and another, causing it to arc across, creating a spark. | 311 | 660 |
ELI5: Islamic banking system. How is it different from interest? | There are two methods that can be used:
1) The bank acts as a traditional investor and just directly invests money into a project in exchange for an ownership stake. This is usually what people hold up as being the definitive model used by Islamic banking.
The problem with this is that it only works for investments in which taking a long-term ownership position is a viable option. IE, this works great when you're financing a startup or an established company that's ok with trading stock for cash. It doesn't work *at all* for consumer debt, such as home/car mortgages or credit cards. It also doesn't work for most established companies, as they're usually unwilling to trade stock for cash, the exception being that they may use that stock as the basis for a Murabaha contract.
2) Murabaha. Murabaha is when you and the bank make a contract for you to sell something trivial to the bank and then buy it back in the future for more money. IE, the bank pays you $100 for a loaf of bread. You agree that in 1 week you will buy the bread back for $120, and to pay the bank you make 12 monthly payments of $10 each. The value of the bread isn't anywhere near $100 or $120, even though you have agreed that it is.
This is how the overwhelming majority of Islamic banking transactions are structured, and is functionally identical to making a traditional loan. The only difference is that the terms of the loan have been phrased to eliminate any mention of the word interest and an Islamic cleric has issued a fatwa legitimizing the loan. | 156 | 153 |
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CMV: I think it is wrong to use China or the USSR as citations of communism as a failed system | For those familiar with Marxist communism, the actual communist society is meant to be similar to an anarchy of sorts. Following a revolution in which the extremely developed capitalist society is overthrown there would be an interim period of dictatorship of sorts which would set up the remaining infrastructure needed for the communist society. Following that, the dictatorship would release all power and let the actual communist society start.
Russia had some manufacturing potential, but arguably wasn't nearly ready enough to proceed to the "communist" phase. Lenin and others sort of wanted to jumpstart it and just skip the long capitalistic society part and go straight to communism. That isn't so much the concern here, but rather the fact that they didn't have nearly the manufacturing society to support it.
China was even worse, they barely had any kind of manufacturing potential and were nearly a complete agrarian society. While they managed to move into manufacturing eventually, the sudden change and poor planning was a massive failure.
Additionally, it seems clear that neither of the society's leaders ever planned to actually leave the dictatorship part. Stalin in particular was just far more interested in having absolute power, and there are some similar tendencies in china, although not nearly to the extent of USSR under Stalin. I think this is the strongest point to make, that neither society were communist to begin with, and were merely totalitarian governments that called themselves communist. Although they had a few communistic/socialistic tendencies, that doesn't make their system of government communism.
Its like when N. Korea calls itself democratic, or perhaps better examples being various middle eastern countries that are "democratic" or "The People's Republic" We never cite them as failures of republic governments, so why should we cite Russia or China as communism failures. | Let's say you are an IT person- who has developed a brand new operating system.
This operating system is just... it's the tits man. Once you get it fully functioning and onto everyone's PCs, it's going to be perfect.
Now, there is one flaw- every time you try to load it up onto anyone's system, it doesn't work. It causes crashes, hardware failure, the like.
Is the system not a failure?
The road to implementing anything is often as important, if not more important, then maintaining said thing.
If one can not get the system off the ground, then said system is clearly rife with problems. | 76 | 118 |
ELI5, How La Croix flavors it’s water? | Ingredients: “only carbonated water, naturally essenced.” What is the natural essence??
EDIT: Hoping I picked a close enough flair | The FDA requires most ingredients in a food product to be listed by their actual name. However, the names of some ingredients can be hidden under the groupings "natural flavors" or "artificial flavors" - depending on the exact production method used to obtain those ingredients.
99% of the time, if a company is able to list an ingredient as a "flavor" then that's what they do, but again, they don't have to. They can use the actual name for the flavor instead.
Some ingredients have stupid actual names. One of those is "essence". "Essence" is the industry term for fruit flavors derived from a specific method of production (basically they subject the skin of the fruit to very high temperature/pressure steam and concentrate the fluid that comes out). That resulting concentrate tastes like the parent fruit but doesn't have any sugar in it.
That's what Lacroix uses to flavor their drinks - its the same natural flavor that is found in a lot of other foods. In fact, Lacroix used to list it as "natural flavor" on their ingredients label. But they've gotten clever and realized that "essence" sounds healthier than "flavor" and since the flavor itself is actually named "essence" they're allowed to call it that. | 168 | 77 |
ELI5 How does face scanning work with twins? | There are different methods of "face scanning," but they all rely on nuances in physical appearance. (More advanced methods use the topography of the face and not just a comparison between images.) They can't distinguish between two different people that look essentially the same, anymore than a lock distinguishes between two people that have subtly different copies of a key.
The accuracy of particular methods, and products that implement them, varies. Identical twins also vary in how alike they are--the environment does have an influence on how you look, not just your genes. But it's safe to say there's a significant potential for a scanner to fail to distinguish between identical twins.
Ideally, biometric markers should never be relied upon for authentication, because you can't change them if they are compromised. They should be more like a user name than a password. But they can strengthen security if implemented alongside a secure authentication method, such as passwords, a key card, etc. | 15 | 23 |
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How is human vision stabilized? | I.e, when you're walking there must be a lot of small movements in the head, but we don't really perceive them. | I believe you're referring to the vestibulo-ocular reflex (VOR), which stabilizes your gaze in space. Other things are also controlled, like focus and pupil dilation. The VOR is driven by two sensors: vision and vestibular organs (inner ear). In the case of vision, the slippage of image on the retina is detected, processed by your visual system, and relayed to your brainstem, where a compensatory command is sent to your eye muscles to rotate the eye toward the slip. This works primarily at low frequencies of motion. The vestibular organs include the semicircular canals, which are essentially rate gyroscopes. They detect angular velocity of the head, rather than image slippage. The information is again relayed to the brainstem and then to the muscles, in part sharing some of the circuitry for vision. Except this one works primarily at high frequencies of head motion, and the two complement each other so that you get good stability across a large range of frequencies.
There are also other contributions to gaze stabilization. Another vestibular organ is the otoliths, which are more like translational accelerometers. There's usually a small component of VOR related to translation and not rotation (translational VOR). Similarly you can sense bending of the neck with proprioceptors, which also can produce a small component. But by and large, vision and semicircular canals handles most of it. Finally, you can also suppress VOR like when you turn your head to look at something, in which case the eyes don't oppose the motion.
Source: Just search vestibulo-ocular reflex, or look in [wikipedia](en.wikipedia.org/wiki/Vestibulo-ocular_reflex).
This is a fascinating area of neuroscience that is fairly well understood in terms of control systems principles.
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ELI5: Why do Jews get so much discrimination throughout human history? | Why is it that Jewish people throughout history have gotten their rights and lives violated wherever they reside in? What is it about Judaism that a lot of humans seem to resent so much? Why is it that this resentment seems to get justified by so many people?
Why do they deserve this much abuse? | Traditional Jewish laws make it impossible to assimilate very well into a different culture; lots of things are required or prohibited, in a way that makes people following the laws stand out. Modern Jews aren't generally too strict about following all that stuff, but in the past they were more so.
And because they were an easily visible minority population, it was easy to point a finger at them. | 34 | 22 |
ELI5: What exactly happens when someone donates their body to science? | Read the book "Stiff". A lot of things can happen to you once donated. Medical schools, crash test dummies, even rotting for research. Bodies are left to rot to test how they react and help police determine cause and time of death. You normally can't choose where your body goes though... | 18 | 53 |
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Thoughts on cheating students | I'm an instructor who works in a department of a university that will remain nameless. Essentially I have caught two students cheating and I feel my department is not handling the situation in the right way. I caught the two students looking at each others papers and talking prior to both of them turning in their exams. I relayed what had occurred in my class to my supervisor, but he/she has decided that nothing can be done, won't take my word for it, would like to sweep it under the rug, and has decided that I should be fired for bringing the matter forward.
I would like your thoughts on the matter. | Document everything and go to the chair of the department. The cheating students aren't as big of a concern now that your job itself is on the line. If the chair doesn't quietly resolve the situation, go to the Human Resources department. At this stage, you have nothing to lose and everything to gain. | 21 | 20 |
ELI5: Scientifically, why can't blood testing using a few drops of blood (i.e. Theranos' purported and testing regime) work? What can we actually test for using single drop blood testing? | Completely putting aside the fact that the Edison machine didn't work, what is and isn't possible for pathologists to do in terms of testing using a few drops of blood?
It's currently most commonly used for blood sugar, and this particular video I watched said that it isn't necessarily reliable for some tests, and some require separation or the addition of chemicals. Another article I remember reading said it can make your potassium levels look like you're dying.
That can't really be it to why single drop blood testing can't work, right? As far as I've seen, no one really has seemed to clearly explain in layman's terms as to why it couldn't or can't work. And likewise, what can actually be done accurately using such a test?
Edit: Thanks for all the really thoughtful and clear answers. Even from the answers alone some people don't seem to agree with one another - hopefully Reddit will help parse out which of these answers are more correct than others! | In a single drop of blood, you can test things that are present in the blood in large quantities. That's great for cholesterol or red cell count. However, most blood tests look for molecules which are not that dense in the blood. If you want to measure the level of PSA, a biomarker for prostate cancer, a traditional test measures in nanograms/milliliter; 1-4 is ok, >6 is a warning. A typical drop in 0.05ml, so you're looking for something in the range of 50-200 picograms. That's only thousands of PSA molecules. To get a good reading, your machine would have to work at an atomic level. | 42 | 24 |
CMV:Leaving the toilet seat up in mixed gender toilets is neither more nor less considerate than leaving it down. | There are frequently comments and jokes in pop culture, usually from women, complaining about men leaving the toilet seat up.
It is sometimes said that this is because "leave downers" don't want to touch an unhygienic thing. However, in order to put the seat down, you are simply shifting the contamination to someone else.
Picking the seat up necessarily requires more prolonged contact than putting it down.
One argument for putting the seat down is that the person using it next is less likely to need it up, since most women and many men will need it that way.
However, leaving the seat down encourages lazy men to not pick it up at all and rely on aim, which is notoriously poor.
> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | If you want to minimise conflict among all parties, the solution is simple: have everyone always put both the seat _and the lid_ down after use.
This ensures that everyone must lift something in order to use the toilet, and that everyone does so with a single motion (lids and seats can be lifted together).
Further, this significantly improves hygiene, as flushing a toilet ejects a fine mist of the contents in to the air above.
With respect to "touching something dirty", when you're finished, you wash your hands... right? | 96 | 80 |
[Highlander] What makes an immortal "powerful"? | I'm thinking more about the chronicles of Duncan McCleod, not his clansman Connor (whom I'm less familiar with).
I've heard a lot about "when you take an immortal's head, you take his power". And I've also seen the videos of the "quickenings", when heads are taken, which are quite destructive (and more destructive for older/more "powerful" immortals).
I also recall seeing some documentaries where the dead immortal sort of takes over the live immortal (Duncan McCleod was once taken over by a "dark quickening", where he effectively became evil, and another where Richie Ryan took on characteristics of an immortal he killed, including falling in love with his girlfriend).
All that being said, I don't understand what they mean when they say, "when an immortal takes another's head, they take his power". It seems to me that Duncan McCleod is "powerful" because he trains like crazy and has trained with some of the greatest masters. Richie Ryan is able to kill many immortals that are much older and more supposedly "powerful" than him, likely because he trains with McCleod.
TL;DR: What does an immortal's "power" actually refer to? | It's the sum of an immortal's strength, knowledge, experience. Everything. Basically all the things that made them a person, their soul you might say. Since immortals, true to their name, live a very long time they tend to build a much greater reservoir of knowledge and experience than normal people, not to mention any they might have collected from killing other immortals. | 10 | 19 |
ELI5:Can someone explain what an isomer is in layman's terms? | An Isomer is a molecule with the same kind of atoms, but they are are a different shape.
Imagine a lego set, put it together one way to make a plane.
Take the plane apart, use all of those pieces to make a ship.
The ship and the plane are isomers of each other, same stuff, different arrangement.
EDIT: OK just might want to make this clear, the ship doesn't actually have to be made out of the plane, they just use the same kind of pieces in the same amounts. | 216 | 113 |
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ELI5: Why do the tips of our fingers and toes need a covering such as our nails? | Nails provide a firm backing, allowing for better grip, finer sensory function, and giving a handy pair of built-in pliers for delicate work.
Imagine you stuck a chopstick through a sausage, stopping a centimeter or so from the end. Now try to pick up something small. That stupid squishy sausage rolls around and you lose your grip. Now add a spoon to the back of the sausage, lightly connected to the chopstick. Now all that stupid sausage doesn't roll around as much, so you can pick things up. In a pinch (pun intended), you can also use the edges of two sausage-spoons to pick up something very small.
That's the "what" of fingernails. As for "why," well, they have a function which arose from modifications to the claws we inherited. Why on the toes? Because they're on the fingers. | 342 | 349 |
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CMV: the "anti-racist baby" book is nothing more than a way to get people who love to virtue signal to waste their money and it does nothing to stop racism | anybody who buys the book specifically because they don't want a racist child should think about why they need a book to teach the child that lesson aby racist person is gunna look at tgat book laugh and walk by. If one were actually trying to change peoples racism they have to be subtle and have some nuance, at the very least in the name of said book. For example the movie slingblade has heavy critiques on racism and sexism but its packaged in such a way that it sneaks in there without realizing which is what makes it effective, being so ridiculously blatant will not change tge people you are trying to change.
Edit: A quote from the book "some people get more while others get less, because policies don't always grant equal access" how the hell is a baby supposed to understand this book? Idk if its spam bots but the reviews are at 19% on google so i guess people arent happy with it lol | Look through children's books that teach skills and values.
Not many of them are there to teach skills and values that the parents themselves lack.
They're there to help parents who already value those things pass them on in a way that works on the developmental level of their child.
So subtlety really isn't an issue. It's not about sneaking in ideas the parents might object to, it's about giving parents a tool to help their child instantiate a value they hold. In that way it's exactly like pretty much any other book for kids designed to teach values. | 494 | 532 |
[Flatland] Could you convince the 0th dimension being to believe in higher dimensions? | He believes that everything is himself, including thoughts and ideas. Would he adopt spoken ideas about higher dimensions as his own so much that he believes them? | I feel like in order to understand the dimensions above you, you'd need to experience the dimensions below. Without those experiences, it's far more difficult to make the leap to understanding something greater.
A Square got to experience Lineland, so when he was introduced to Spaceland, he was able to understand the experience.
The Sphere (and the reader) gets to experience Flatland, so you'd think that if we were pulled into Hyperspaceland, we'd be able to understand what's going on - if we're willing.
But in Pointland, there's no step below, so Pointy couldn't learn to recognize the ignorance of believing there's nothing greater than what you can see. Because of that, and because he's all that he's ever known (compared to the other dimensions, which are densely populated by segments, shapes, and beings), it'd be pretty hard for him to learn what a "line" is. | 31 | 41 |
If I take ice II at 500MPa and -80°C, and reduce the pressure to 100kPa, will the ice reorganise itself into ice I? Does it need to be melted in order to transition between its solid phases? | Do any of the solid phases of ice form a stable configuration that can be taken out of its usual temperature-pressure boundaries once formed? | I don't know about ice specifically, but for other materials, phase changes between different solid phases certainly does take place. For example the changes between the different phases in steel is used in order to create the desired microstructure to give the desired bulk physical properties for particular applications of steel. | 241 | 1,017 |
What makes someone smart? | From a psychometric perspective smartness is a relative measure of ones' problem solving ability compared to the rest of the population, and it can be divided into two categories: fluid and crystallized intelligence.
Fluid intelligence is ones' ability to solve novel, previously unencountered problems with nothing more than just raw brainpower and with minimum additional knowledge. It's the most culturally fair aspect of the general intelligence, highly correlated with ones' biological makeup and is the hardest part of intelligence one can ever hope to change in any significant way. It's correlated to reaction time, working memory capacity.
Crystallized intelligence is the knowledge and skills based part of the general intelligence. It's the collection of knowledge and the mental skills acquired through lifetime, like language proficiency, factual knowledge, etc..
Generally we don't quite know what intelligence is. We would have already made super AIs by now if we knew. But you can think of it as the ability to use the environment to set and achieve beneficial goals efficiently.
What can you do to increase your intelligence? For fluid intelligence; be mentally and physically healthy: have a good and nutritionally balanced diet, be physically active and fit, socialize as broadly as you can. For crystallized intelligence; learn as much as you can, don't shy away from complexity, learn how to manage the things that you don't understand (no one understands everything, smart people learn how to manage the unknown), learn to simplify, and don't think that you are not smart enough.
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ELI5: How did ancient civilizations know so much about the solar system with limited technology? | Ancient civilizations were able to track the stars and objects in the night sky. While they didn't have telescopes, they had far less light pollution, allowing them to see a lot more stars far more easily than we can. | 1,381 | 1,092 |
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The strive for knowledge has been shattered by the public education system. CMV. | For quite some time I have been looking into the priorities and the structure of the American education system. I myself am a senior in high school and, like many others, always wonder what the point of it all is. But what I've noticed is that when students ask this question, they do it out of laziness and lethargy. To put it simply, they just don't care about any of the information. Previous posts on this topic attempt to blame this disinterest on teachers, parents, etc. Whatever the reason, I would in turn like to present my view on how the public education system has turned the endeavor for knowledge into a single desire for exceptional grades and university acceptance.
From my experience, what I have noticed is how grades have engulfed everything. A student's highest priority is to get all As in school, or to simply pass a certain subject. Not once have I heard someone make the new years resolution of learning something new in school. It's always to do better grade-wise. It's not exactly their fault either. The material being taught at school is centered around a [punishment-rewards system](http://www.alfiekohn.org/books/pbr.htm).
This disciplines kids, not educate them. Even a lion learns to behave in fear of a whip - but you would call such a lion well trained, not well educated. In the case of the modern public education system, this "whip" is supposedly evaluating a student's work to the point where the assignment will only achieve full marks if it reflects previously generated exceptional works. How, then, do we move forward if we keep imitating the past?
What I think none of us understands is that intelligence is dynamic and possibly endless. How can we possibly measure that with a tiny scale that focuses on, for lack of a better word, "busy-work"? We're given packets and worksheets and graphs to absorb and memorize - not to understand. If we've memorized it enough, we get a sufficient grade.
Then we arrive at standardized tests that attempt, as another redditor had put it, to measure how well you will do in college, not how intelligent you are. If you take a look at various SAT/ACT practice and training courses, you will notice that they don't teach you the material. They explain strategies to take the test in the best way (as in, process of elimination, cross this and that out, etc.). These tests now dominate and obstruct the education system, instead of support it.
In conclusion, I believe that the education system has turned schools into factories. Students are therefore enduring school instead of enjoying it, as they should. This leads to extreme stress and can contribute to harmful mental injuries.
I accept that my views are not exactly conscientious, and I would like someone else's opinion on the matter that may or not CMV. | The purpose of school is to give you credentials to eventually enter the workforce/adult society. Intelligence/learning something new by itself isn't rewarded because they aren't rewarded in the work-force/adult society.
Edit: The part where your view is wrong is that you are looking to the education system for something that it doesn't do and it shouldn't prevent you from enjoying learning new things or striving for knowledge. | 12 | 86 |
CMV: Capitalism is a greedy killing machine and it's not okay. | The Left vs right politics war waged on humanitarian leaders by greedy elites (oil billionaires mainly) who need extensive therapy and mushrooms (and quite possibly a hug)
Let me explain
Mental health awareness is purposely suppressed in America because it's "bad for business". The more people that become aware of their own mental health and sense of self-worth, allowing themselves to focus on what they (and the rest of society) actually need to be doing for the betterment of ourselves and everyone around us, the less and less people are okay with scummy behaviour exhibited by greedy corporations, the big guys on top realize this and are now actively suppressing this stuff rather than just passively and it's time we did something about it.
Oil billionaires use radicalization to fund political wars so the big companies that can mass produce can sell resources for wars. This way all the misguided but intelligent greedy souls in need of therapy can stay rich and keep getting richer. They also use lobbyists to create bought-out congress members who can gear the country towards bailing them out and keeping them in power. Artificial intelligence is going to a world of terror in the name of Capitalism and I fear for our future. | In the past two centuries, capitalism has raised more people out of poverty and into middle class prosperity than any other system of economy. Yes, it is the worst system, except when you compare it to all the others. | 69 | 28 |
ELI5: After a tooth is removed how is it that the hole left gets completely filled over time? | I understand how the wound would heal but how does the body know to fill in the entire hole left by the tooth removal? That space didn’t have any gums before, since a tooth was there but it all gets filled. | Dentist here - inflammation and normal trauma processes carry out cell growth, tissue differentiation, repair, etc. like they would for any wound. The body doesn’t like voids and will fill them. They first heal to close the wound, then slowly over time remodel into a smoother shape (bone and soft tissue). | 49 | 51 |
ELI5: Why does a fruit "bruise" when dropped. What actually happens that causes the change? | When the cells within the fruit are damaged, it allows oxygen in. When oxygen gets in to the cells, it reacts with the chemicals in the fruit in that area. The result of this reaction is a darkened color to the affected areas of the fruit. | 13 | 17 |
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[SCP Foundation] What if SCP-140 got filled in all the way to the early 1700s? | http://www.scp-wiki.net/scp-140
This magic book is capable of retroactively changing history to incorporate the existence of a powerful ancient nation ruled by evil sorcerors.
Every time a type of fluid visible enough to write with comes in contact with the book, the history of the "Daevites" is changed.
Real-world history, such as archaeological discoveries, change retroactively every time the book is added to.
The Daevites are extinct, but the date of their extinction gets closer and closer to the present.
Right now, it's far enough in the past that it has no real affect on the present.
However, what if the book somehow got filled in enough to reach the early 1700s?
How would moving their extinction to a mere 300 years ago affect history? | Consensus reality would be profoundly different - provided that the Foundation did not manage to successfully eliminate evidence of the Daevites from the historical record, and wide-spread use of amnestics and deep infiltration of history, archaeology, and anthropology departments would be costly and difficult; the greater spread and survival of Daevite hemomancy and herbomancy, artifacts, genetics (one can imagine intermarriage among noble families, for example), even language would cause widespread anomalous activity and support of neo-Sarkic cults, and the possibility of syncretism with established religions or governments would make containment even more problematic.
In addition, all indications are that the initial retroactive removal of the Daevites from mainstream reality was only accomplished with means that are no longer available; the Foundation might have to enlist the aid of the Children of the Night to re-establish containment, and that's potentially trading one SK-class dominance shift for another. | 12 | 17 |
ELI5: How exactly does Deja Vu happen, and is it abnormal to experience it daily? | I remember one of my professors giving me this thin, run down explaination of it, but he didnt say more than two sentences. I still don't understand it. | Humans have two kinds of memory, a short term memory that lasts a few hours and the long term memory that archives the memories. What you perceive from your senses is processed in your short term memory and is eventually shuffled off to long term memory when the brain no longer deems it useful for the current time. Deja Vu occurs when the signals to your short term memory either go to long term memory first or ends up in both at the same time. Seeing the sensory input in both the short term and long term memory confuses the brain into thinking that it has experienced the event in the past and at the current time creating the feeling that you have experienced before.
Since it occurs when something goes wrong in the brain anyone who gets it on a daily basis should seriously see a neurologist on that. | 53 | 37 |
CMV: The US Government should allow transgender people to serve, but should not pay for their surgeries | I'm not interested in arguing whether transgender people should be allowed to serve in the military, I'm more interested in the second part of my title. So starting with the assumption that trans people *can* serve in the military, why should the government pay for their surgeries and hormone treatments?
Two big arguments I think support my case:
1. Sex reassignment surgery is an elective plastic surgery that only changes a person's physical appearance. The government wouldn't pay for an elective nose job or breast enhancement, so why should they pay for sex reassignment? The military medical coverage should only pay for medically necessary procedures and plastic surgery that arises from deformities sustained as part of service (i.e. A nose job for somebody who's nose was mutilated in battle would be justified)
2. I also don't want to set a precedent for pre-op trans people to think that joining the military was a way to get a "free" sex change. That would only encourage more people to sign up for the military only so that they don't have to pay for their own surgery, which is not what the military is for. We shouldn't make military service a bitter pill for desperate, but poor transgender people.
I'm very luke warm in this opinion, so I'm curious what people think.
Edit: just noticed I wasn't clear in my title. I'm referring to military service here, not other civilian government jobs | 1. Many would argue that these treatments are not "elective". Gender dysphoria is a documented mental illness in the DSM-V and one of the established treatments is transitioning (inclusive of the medications and surgeries necessary to enable such a transition). While not all transgendered people are gender dysphoric, many are. To deny them the accepted treatment paths for that disorder would be denying them the same privileges that we give to people with any other diagnosed disorder, be that mental or physical.
2. How would this be any different than people who sign up for free college using the GI bill or free money through enlistment bonuses? We provide financial incentives all the time for people to join the armed forces - why should the financial incentive of free healthcare be any different, so long as they are prepared to meet the obligations of service? | 16 | 21 |
CMV: Healthy animals should never be put down simply because they’re not getting adopted. | I understand the issue about space, accommodation and how many shelters are already struggling taking care of the ones in shelter, needing 24/7 care and attention. But do we put down our family who are going through similar or more painful health issues? Family who’s fighting through cancer, or elderlies who are too old to care for themselves, we take on the responsibility for them. Then why can’t we try and do the same for animals who are much more helpless and in need of support instead of putting them down simply because it might be too much work and money?
I may not know all the specific details that go into this decision, so help me learn please? | Animal rights advocates/vegans, say that we should be adopting the animals that we can, make sure that animals are properly spayed/neutered so that they don't breed in an uncontrolled way and crack down on dog farms and breeders which bring dogs into the world , the unwanted dogs of which get thrown away out of sight and out of mind.
Unfortunately, shelters will need to put dogs down just as a matter of lack of resources. What else is there to do? Keep them alive but isolated and under-cared for? Send them to a home that may not be right for them where they are likely to suffer further?
You need to look at the broader picture. These animals absolutely have a right to life and it is our responsibility to take care of them but where we can't give them a good life then they will also just be suffering anyway. If you care a lot about this topic then you need to ask what practices led to all of these unwanted dogs and solve the problem there instead of downstream after the problems are difficult to solve. | 25 | 88 |
starting out my journey in philosophy with Kant , is this a good idea ? Any tips? | I had my first contact with philosophy in class when we studied Socrates .
I was blind but now I see, my eyes are open and I know I want to actually get into philosophy.
I have chose Kant's critique of pure reason as my first book and I wanted to know if you guys have any tips or important things I should know before going into it or as I read it .
Or if maybe you think this is a bad idea or a decent one .
Cheers ! | Following the historical sequence is often a good way to go. With Socrates you make a good start, and since you read about him in Plato, it is a good idea to spend more time with Plato.
There is a strong historical progression from Plato, to Descartes, to Hume, to Kant. Kant's philosophy, is very much part of that progression. | 18 | 27 |
What are your main reasons for being anti-capitalist? | [assuming you are] | The duty to maximize profits can lead for example to environmental degradation, colonialism and worker exploitation.
The incompatibility of the unfettered accumulation of private wealth with democracy. | 64 | 49 |
ELI5: What is a credit score, how does it work, and why is it so important?? | I’m sorry if this basic knowledge, but I honestly don’t understand any of it. | A credit score is a number that financial institutions use to judge how likely you are to pay back any loans or credit extended to you. The higher the score, the more stable and trustworthy they view you.
The score is important because many large purchases in life usually require a loan. For example, a car loan or a home mortgage. The better your credit score, the better terms the bank will extend you on the loan. | 24 | 32 |
How come when ice is in my cup, and i rotate the cup, it stays in the same position? | This isn't really a joke post, ive always wondered and its so annoying when the ice is in the back of the cup, you have to put the cup down and walk around it OR put your finger in the cup, which isn't that nice. | It is Newton's first law, the law of inertia, that you can use to describe this situation: The ice will remain at rest until an external force acts upon it.
If you move the cup from side to side, you're pushing on the side of the cup, the cup is pushing the uncompressible water on one side and pulling the water from the other side, and it's the water that's pushing on the ice, so the ice moves as well. However, when you turn the cup, the cup isn't really pushing on the water. Every bit of cup is moving into an area previously occupied by more cup.
Now, you probably impart a little bit of motion on the water as some water is dragged along the walls of the cup as it turns, but it's a much smaller effect. This works much better with thicker fluids.
If you want to move the ice to another side of the cup, try moving the cup in small circles (without rotating it) for a while. The motion of the walls of the cup will impart momentum on the sloshing liquid, moving it in a circle.
[edit:sp] | 58 | 31 |
ELI5:How does an algorithm prove a mathematical theorem? | I recently heard in a talk that machine learning algorithms can now prove some mathematical theorems .what do they mean when they say that?Theorems aren't some mathematical problems that can be solved by following a series of steps that can be automated for all I know. | The rules of mathematical logic can be followed by a program just as easily as the computer can perform arithmetic. It's not all that complicated to write a program that knows how to take a set of true logical statements & combine them (using the rules of logic) into new logical statements that are also true - we've been doing it since the 60s. If you combine enough logical statements, you'll eventually find a series of these that proves the theorem you wanted to prove.
The hard part comes in choosing how to combine your facts into new ones, figuring out dead ends that go nowhere & doing it all fast enough to figure out something worthwhile in your lifetime. On top of that, finding the *shortest* proof and finding proofs that are easily understood by humans is also a challenge - a 5000 page proof is no use to mathematicians trying to understand what's going on. | 21 | 52 |
Are quantum fields in any way similar to classical fields? | I understand classical fields as being functions of space with spatial(-temporal) coordinate inputs and scalar, vector or tensor outputs (like temperature being a function T(x,y,z,t) with a single scalar output). But when people talk of quantum fields, they talk of "exciting the field to produce particles" and other things that refer to quantum fields more as physical media that can be disturbed and picked apart. Am I missing something big here? Or is QFT just so complicated that it's not worth comparing quantum fields to classical ones? | In the canonical picture, quantum fields are operator-valued fields (distributions, to be more precise). The Hilbert space on which they act is spanned by number states. Each number state consists of a given number of particles with given momenta and other quantum numbers (spin, color etc.). In fact the \*free\* fields behave like a set of harmonic oscillators for each momentum/spin/color/etc. Of course not every state is a number state, but they provide a basis by which you can express any state by linear combination.
In this picture, the fields are just operators that create and destroy particles, but the particle content is in the abstract quantum state.
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The path integral picture is closer to the classical interpretation, but the relationship to particles is a bit more difficult to see. Basically, there is the path integral/partition functional, which consists of a sum over all possible classical field configurations weighted by the value of the action on the given field configuration. Thus all possible field configurations contribute to the amplitudes and expectation values. In the classical limit, only those configurations contribute for which the action is stationary, eg. those that satisfy the classical equations of motion.
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TL;DR: In the canonical approach, fields are just tools. In the path integral approach, physical processes happen by summing over classical fields, even those that do not solve the (classical) equations of motion. | 71 | 502 |
ELI5: How does adapting to high altitudes work in the body? | Today is my first day in Bogota, Colombia. Elevation of 2.6km. I don't have altitude sickness like some, but I'm very short on breath after even minor exertion (walking one flight of stairs).
I know this goes away after 1 - 3 days, but what is actually happening in a person's body to adapt so quickly? | At high altitudes, the body needs to produce more red blood cells to be able to carry the little oxygen available throughout the body. A similar situation happens with the Badjao tribe, Phillipines, which are regarded as the best freedivers in the world, with spleens 50% larger than normal, and thus can store more blood when the need arises and the ability to stay underwater far longer than average, because they also use the oxygen more efficiently, and they also see clearer underwater than the average human, because they spend so much time in the water hunting fish, IIRC. | 15 | 19 |
ELI5: How can car insurance companies adjust their prices for people based on age/sex and not be sued for discrimination? What stops them from adjusting rates based on race? | I know they base their rates on actuarial information, but what is to stop them from doing the same thing with regards to race? It seems like insurance companies are allowed to exercise a degree of prejudice that most other businesses would never get away with. | Two things that are relevant:
1. They can discriminate on any factor if they have scientific evidence that it increases or decreaes the cost of insuring you. There is clear evidence that younger drivers are more likley to be involved in a crash; therefore it is legal to charge them more.
2. The legal standard for discrimination is different depending on what the basis for the discrimination is. Legally race is extremely difficult to justify (almost impossible), sex is difficult but possible, and age is relatively easy to justify. | 30 | 39 |
ELI5: When you speak to people that understand fractals, they say everywhere and everything is fractals. I have tried to understand fractals but I am completely lost, can someone please explain it like I’m 5? | Side note: I tend to find these people very eccentric, I sorta feel like they can see the matrix :) I am absolutely fascinated by this but completely lost :) | Let's say you're trying to measure how long a coast is. The rough estimate would be to find the end points of what you're trying to measure, and take the distance. Of course, this won't be accurate, because the shore isn't quite straight - there are ins and outs. Alright, no problem, we can measure smaller distances.
The problem is, the longer you do that - the smaller the pieces you look at - the more details you'll catch. You should probably include the cove, but what if the cove has a large rock at the shore where water doesn't quite reach around? What with smaller rocks? Do you measure their surface? What about the sand that water goes around and into? Molecules?
The closer you look at something - even where you would've previously thought you have something smooth, you find that it's made of more nonsmooth stuff. A fractal is a shape where this goes infinitely - not quite unlike most of real world. One of their most interesting properties is that they do not have a measurable length - like the coast example. | 37 | 21 |
ELi5: What is White Privilege? | White privilege is how things are generally better for you because you're white compared to those who aren't white in the same situation.
While you not many people these days actively think and act upon you being white just that fact you are white gives you an upper hand.
It's not so much a benefit but a lack of detriment. A good stereotype would be a black man walking towards you at night in a bad area, if he was white you wouldn't feel so threatened.
It's similar to how you have very few women in certain fields just because they're women, there are lots of fields where it's full of white people. | 44 | 19 |
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[DeadSpace]What kind of considerations have to be made when cracking a planet? | Surely removing/harvesting a planet can have knock-on effects on a solar system when we begin harvesting a planet. What kind of decisions are made, are there things that could go wrong? What are the risks beside the marker incident? | I imagine it is similar to the considerations one makes before drilling for oil. So, if doing it the right way, impact on surroundings, potential dangers, etc.
If you do it the american way...
"Is there oil there?" "Idk...maybe." "We drill at dawn." | 19 | 22 |
ELI5: Why don't psychologists and psychiatrists work in tandem? | If psychologists made the diagnosis and psychiatrists reviewed it, the entire process would be more comprehensive. | Psychologists and psychiatrists normally work together, more or less. A counseling psychologist will refer a patient to a psychiatrist if they feel the patient needs help beyond what the counselor can provide. For instance, if a psychologist has a patient that's schizophrenic they would refer them to a psychiatrist after the initial diagnosis. If a patient has depression issues the likely course would be therapy with the counseling psychologist and medication and occasional checkups with the psychiatrist to see how the meds are working. If the patient needed behavioral therapy then a psychiatrist most likely wouldn't be needed. | 57 | 57 |
CMV: There is no such thing as ‘the one’. | My theory is that there are actually many ‘the ones’ in each city. It’s just a matter of whom you happen to meet first out of that pool of people.
Most of us know someone who has been widowed. Many of those widows/widowers will eventually remarry or at least settle down with someone else. They often feel as though their second spouse is just as right for them as their first, sometimes even more so. How does that make sense when they believed their previous spouse was ‘the one’ until the day they died? It makes sense because there isn’t a singular ‘one’, there are a lot of them. We just aren’t aware of the others.
There are situations in which little details seem to confirm that someone is indeed the one and only love of their life. For example; “My wife and I grew up in the same town but didn’t know each other but met on vacation 4000 miles away. And it turns out our grandfathers used to be best friends!” But let’s be real - coincidences happen every day. Odd ones. Far-fetched ones. But they happen. And they serve to make us feel even more secure in the relationship. | Imagine that we can measure couples compatibility on single measurement. Now center the map around you and assign compatibility score to every person around you. We can assume that compatibility follows normal distribution with fat low tail. This is fancy way of saying that half of population (same sex) is not willing to date you (low compatibility score), most people are average match and few are good match.
Now you can pick highly compatible partner near you if you search long enough but this doesn't mean they are most compatible. In order to find that you need to expand your search radius. But higher your target compatible score goes the search radius increases exponentially. Like you can find a great partner within 100 miles but next partner that is better is 1000 miles away and after that next better partner is 10 000 miles away. It becomes harder and harder to find "the one" or "the one with the highest compatibility score".
And this why people settle to lower score but this actually makes it harder for searchers. Now your "the one" is already in a relationship and you won't find them even if their compatibility score is higher with you than with their current partner.
TL;DR: You can always find more suitable partner but you have to travel further, spend more time and despite all this your "the one" might already be in a relationship. | 36 | 88 |
ELI5: Why does Tea and Coffee taste bad when it's watered down, even though they're mostly water? | Coffee and tea are a specific ratio of water to "stuff;" the stuff is the oils and other chemicals from the coffee beans or tea leaves.
So when you brew a cup of tea, the box of tea will tell you "Steep this tea bag in X water for Y minutes." That's like a recipe - it makes sure there's the right amount of stuff vs. water.
Pouring extra water in there messes up that ratio, and it tastes worse. Just like if you put too much flour in a cake or too much water in a soup.
| 18 | 41 |
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ELI5: Is the 4th dimension something that we know actually exists? Or is it just a concept? | We have three spatial dimensions.
Length, Width, Height.
Using those three dimensions you can plot a spot in any space.
We do not know if there are more spatial dimensions, if there are, they are likely to be things we're not capable of observing.
What does it even mean to have a 4th spatial dimension, when you can plot any location in space using only three?
That's beyond the scope of eli5.
We have a temporal dimension as well.
We don't know exactly what this temporal dimension *is*.
We know what it feels like. It feels like the past moving through the present to the future.
But Einstein turned that concept on its head when he declared the speed of light is constant.
That's also beyond the scope of an eli5.
Einstein called this Space-Time and it's the mathematical representation of both space and time as a singular entity, when you pull on one, the other is pushed. When you push on one the other is pulled. Space and Time are connected.
But we don't know if time is an actual dimension, or if it's just the emergent property of having the ability to move through space while being constrained by the constant nature of the speed of light, which dictates that Space and Time *must* change, and that they change in ways that are correlated to one another. | 618 | 329 |
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Are the better educated more likely to be left wing or right wing? | I have often heard that their is a positive correlation between education and left wing believes.
At the same time, however, I know education level also correlates with wealth, and the wealthier are more likely to be conservative.
So how does it work out? | The quick summary of patterns in the General Social Survey:
- At any point in time, slightly more Americans identify as conservative than liberal.
- Both the least educated (< HS) and the highest educated (grad. degree) self identify more liberal on average. The middle leans conservative.
- Partisans in either direction are better educated than moderates on average.
- The overall correlation is that liberals are slightly better educated on average. This gap is widened when looking at white Americans only.
- More educated people generally have preferences that don't fit tidily into a left right spectrum. To summarize, controlling for race, income, sex, and party affiliation, more educated people lean right on economic issues and left on social issues. Social issues seem to carry more weight in defining one's self identification as liberal or conservative. | 51 | 43 |
CMV: Attractive people with bad personalities are still more accepted than any unattractive people. | As a woman who is very young looking, not developed physically (tiny breasts, and skinny with no curves in general), and just generally not attractive also due to difficult skin and a chubby, undefined face...I think I have a good reason to believe this. The amount of conventionally attractive people I've met who just seemed to be treated nicer than me in every situation, kind of gives me the impression that the world revolves around appearance. There have been some right nasty people in my life who I feel like got away with being that way because they had a nice face or body.
Okay I agree this could just be something in my head because of low self esteem or something, but I think more attractive people get more attention in most situations. Like when I go out with certain friends who are gorgeous and we see someone else, whether a stranger or friend, like 90% of their attention is on the more attractive friend despite me trying to be involved in the conversation. I'm talking about both platonic and flirty situations, like I understand the latter because people want to date attractive people, but am I not allowed a normal conversation with someone because I'm not 'pretty'?
I have literally seen people be so nice and friendly to one of my friends and then the friend leaves for a moment and their entire demeanor changes because its just me there. I don't mean they feel awkward because maybe they don't know me as well, I mean they would blank me deliberately and not in a shy way, they made it obvious they didn't want to talk to me because I would be right there trying to at least make small talk and..nothing. Completely disregarded. Coincidence? I think not.
I only really have anecdotal evidence of pretty people getting away with stuff, so not sure if you'd be interested to hear that but I'll include one just in case. So this girl at my high school was a total cunt, the small amount of times I spoke to her she left a sour taste in my mouth just by the way she acted and things she called me. but she was like the popular girl everyone loved?? Like it didn't matter how nasty she was, I understand she may have been dead lovely to all these other people and just a bitch to me, but i'm pretty sure its not because she was a bitch to most of my friends as well.
I should probably mention that many of my past and present friends have been much more attractive than me, I don't know why that is, but maybe that has effected my opinion on the subject as well as my low self image etc. I also have loads of memories of talking to people in school where they would outright just call me ugly to my face like it wasn't a bad thing to say, so yeah maybe people have stopped outright calling me ugly but that's probably just because they've matured and realized its mean to say stuff like that but it doesn't mean they're not thinking it and making an either conscious or unconscious decision to blank me or treat me differently to other people.
So hopefully I've made my point, sorry if it was a bit rambly and I look forward to being proven wrong haha :)
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Being physically attractive is a plus for social attractiveness. But so is a nice personality and positivity. At some point there will be a cross over point in interest for every person, depending on how superficial they are. Try being very cheery and interested in the other person.
If you were in a room with justin bieber and stephen hawkings, who would you interact with? Was it the more attractive one?
If attractiveness was the only factor that mattered, you would not see partners with very different attractiveness. The very fact that hot wife, ugly husband exists means some people (in this case the wife) values thigs more than attractiveness (probably humor and success). | 27 | 128 |
ELI5: Why do I feel like I'm losing weight by eating 2000 calories of grilled meat and vegetables, but not when I consume the same amount in ice cream, fried foods, and fast food? | Biologist here!
Our body gets calories from three main sources; fats, carbohydrates and proteins. While one calorie from a healthy food will provide the same amount of energy as one calorie from an unhealthy food, they will have different effects on the body.
* Fats
There are three main types of fats; saturated, unsaturated and trans fats. Saturated and trans fat can increase your cholesterol levels which can lead to heart disease and strokes (found in a lot of your junk food). Unsaturated fats lower your cholesterol levels which can prevent heart disease and strokes (vegetable oils, nuts, avocados, olives, seafood).
* Carbohydrates
Carbs are made up of sugar molecules. The more sugar molecules are linked together, the more complex the carb becomes. The two main types of carbs are simple and complex. Simple carbs are unhealthy. They are digested and absorbed quickly leaving you hungry soon after eating them (cookies, donuts, candy). Complex carbs are healthy. They are digested and absorbed slowly which keeps you full and prevents cravings (legumes, vegetables).
Certain diets, like Keto and other low carb diets, are healthy and most of the carbs are coming from vegetables. You don't actually need a lot to keep your energy up.
* Proteins
Proteins are made up of amino acids. While our body can create some of them, it can't create all of the necessary amino acids. There are two types of protein; complete and incomplete. If a protein contains all of the essential amino acids, it is complete. If it lacks one or more of the essential amino acids, it is called an incomplete protein. While you can get complete proteins from fast foods, they come with the lousy carbs and fats.
See it's not the calories that matter as much, it's what's in those calories. By eating junk you are also missing out on essential nutrients, vitamins and minerals that are found in non-processed foods (vegetables, meats, fish, nut, etc.).
| 17 | 20 |
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If you have a single molecule of a substance, what state of matter is it in? | If you had say 1 molecule of water is it a solid, liquid, or gas and how do you tell? What is the minimum number of molecules required for something to be classified as a solid liquid or a gas? | There seems to be a lot of dicussion about how to define temperature and pressure for a single molecule. Though the simple answer is that it would be in a gas phase. Why? Well consider an ideal gas is defined as the particles having *no* intermolecular interactions, it's not that big of a stretch to realise that when you have only a single molecule you actually have an ideal gas.
The temperature in such a single molecule in a box would be defined based on entropy and energy. The entropy (S) is proportional to the logerithm of number of available quantum states at a fixed energy (U), and the temperature is then given by T=1/(dS/dU). The pressure could be found through similar paths, but the easiest is just to assume an ideal gas and take p=n R T/V, where we know both n and T.
| 60 | 123 |
ELI5: Why do so many pieces of classical music have only a technical name (Sonata #5, Concerto 2 in A minor, symphony #4, etc.) instead of a "name" like Fuhr Elise or Eine Kline Nachtmusik? | I can only speak for myself, but this makes it really hard to keep track of the songs I like. I love listening to classical music but if you asked me my favorite artists I would have difficulty telling you specifics. | Earlier, this was just a tradition, but around 1800 or so an idea was growing that music should speak for itself without the need for words or descriptions. This term was "absolute music" and it was thought that using words — even in a title — was a crutch that would hamper music's power to speak to ideas and emotions that we cannot express with words. So a lot of music, self-consciously, was just referred to by its genre. | 7,545 | 8,795 |
Role of LinkedIn in academia | Is it important to have a LinkedIn when you’re working in academia? If you’re not on LinkedIn, what are your reasons? | LinkedIn is primarily useful when job hunting, both as a platform for finding jobs and just general information gathering about different people's career paths.
I also find it very useful as a professional contact list that's always up to date. Particularly outside of academia where it's common for people to change jobs every few years and lose access to whatever professional email address they had when you were introduced. | 44 | 42 |
ELI5: Why do we lose so much of our balance when we close our eyes? | Your sense of balance is dependent on your ears mainly, but your brain likes to use your eyes to keep focus on your environment. Without that vision, we get really confused. This is why you get dizzy while reading in the car. | 40 | 92 |
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ELI5: Why is walking in bad/old shoes considered unhealthy, but walking barefoot isn't? | Shoes wear unevenly and because of this puts unnatural pressures on your foot affecting your entire posture which can damage muscles and other connective tissues all the way up into your shoulders and neck.
Walking barefoot only puts bad/unnatural pressures on your musculoskeletal system if you have a deformation like flat foot. | 170 | 96 |
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ELI5: How do Dictators maintain power when it seems that most of the country is against them. | With what is going on in The Middle East and South America where is seems like significant portions of the county are against a particular regime, how do these dictators maintain control? I understand they have the armed forces but surely people in the respective armies must be against the dictator as well or at least have family that is demonstrating. | - Surrounding yourself with corrupt people who financially gain from your policies, and who in return provide you with "donations"
- Ensuring the wealthiest citizens benefit from your policies and are exempt from prosecution for the laws they break
- Changing laws to marginalize opposition
- Silencing journalists
- Employing state media to control the narrative
- Creating nationalist fervor through a perceived outside threat from foreigners
- Indoctrination of ideology in schoolchildren
Many countries that are not currently dictatorships have already checked off a few of these boxes, including the United States. | 239 | 280 |
[Harry Potter] How has the magical community managed to keep up the masquerade this long? | Sure, there have been a couple slip-ups (Salem comes to mind), but for the most part, there have been no major leaks or anything. How does the community stop random trolls from spilling the beans? Extremist groups who have tons of evidence ready for Muggle media? Various dark lords who would seek to take over the magical *and* Muggle world? With all its faults, is the Ministry just *that* good at memory-wiping every single non-related Muggle who finds proof of magic? | 1. **Wiping memories.** Wizards do a lot of this. *Obliviate* and False Memory Charms are the two biggest tools there.
2. **Crime scene clean up.** Magic like a mending spell allows a wizard to clean up a trashed breakfast nook almost instantly. Healing spells can fairly easily patch up a person who's had their legs broken.
2. **Unplottability and Disillusionment.** Wizards have magic that turns people away places that they're not allowed to see, and magic that makes them unable to see it. It's debatable whether a muggle could even *see* a troll - we know for a fact that they can't see (only sense) Dementors.
2. **Bias against the unnatural.** Oh, so you have a shaky home video movie of someone flying through the air? Well, it's probably a prank or a hoax. You don't have a video? You're probably insane, or mistaken about what you saw.
3. **Worldwide organization.** It's not just the British wizards - it's every wizarding government in the world working in harmony. They also have a multitude of fast travel methods. Wizards also have some level of buy-in from muggle governments.
4. **Small population.** There just aren't that many wizards. In the muggle world, it makes sense to talk about an extremist group forming from the millions of people, but the population of magical Britain is tiny, and the same goes for the rest of the world. Extremists are less extreme, and less likely to find co-conspirators.
18. **Time period.** At the time the books take place, there's no internet, no quick video sharing, and home video itself had only been around for a limited amount of time. That leaves definitive proof much harder to come by and much harder to share.
That said, there are a few documented cases of wizards trying to break the masquerade, but none have been successful, mostly because of their Ministry's wide-reaching powers (and partially the ineptitude of these crusaders). | 35 | 25 |
ELI5:Is face blindness restricted to humans or is this something that's been observed in other species? Is it understood what causes it? | Not many animals rely primarily on sight to recognize others, and fewer still rely primarily on facial features.
I would imagine if it happens in animals, it is pretty uncommon and restricted to our closest animal relatives. | 29 | 83 |
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CMV: Religion should have stricter boundaries or regulation | A little about me, I grew up in a very Evangelical home in Texas. My mom and pretty much everyone around me was on the far right. Democrats were effectively in league with the devil and pretty much anything that wasn't explicitly Christian was of the devil. In 2004, pastors told us you were not a strong Christian if you didn't vote for Bush. I would like to include that this wasn't a small cult meeting in a strip mall. When I left the church, it was at about 12,000 members (I think it's north of 20,000 now). Southern Baptists in Texas are pretty fucking bizarre.
I went to private schools most of my life, not because the education was better but because they didn't teach you about things like sex and evolution. I left the religion and see myself as an agnostic atheist. I don't know that I can say with 100% certainty that there isn't some kind of higher power out there or what the nature of it is. However, I believe all religions on Earth are man-made and not divine in the least.
I just wanted to set the stage on where I am coming from. So I fully believe in the freedom of religion and believe that people should be free to practice. That being said, I feel that in the USA, we tend to give carte blanche to religions, especially Christianity. They are allowed to act in misinformation campaigns to prop up their religion.
&#x200B;
For example, they are against pre-marital sex. One common tactic they use is to lie about biology. They may tell you that you can only get an STI if you have sex outside of marriage and God will protect those who have sex with only their spouse. While technically true (if both you and your partner have only ever had sex with each other, chances of having an STI is slim) it is built on the idea that you are guaranteed to get an STI if you have sex. They even tell you that condoms don't work and safe sex is a myth where medical science wholly disagrees. The key is to have a realistic discussion around sex and proper contraceptive use but instead, abstinence only is their approach backed up by fear tactics.
&#x200B;
Let's talk a bit about televangelists. I don't see how they are any different than any other scam. "Give me your last dollar and you'll receive ten times the blessing." If you don't get the blessing, well it's just not your time. Keep the faith and keep sending me money.
&#x200B;
Let's also talk about how they prey on people with mental health issues. Many televangelists and pastors talk about demons as if they are real things and they pose a real threat. If you are a sane human being, you will likely say "what the hell is this dude talking about?" I do think they prey on people with some form (if not mild) of psychosis. These people should get some kind of assistance to improve their life and not be preyed upon. The church has had a terrible history with mental health. While they are SLOWLY changing their tune, many pastors will tell you that therapy is a waste of money, get your heart right with God (things I was literally told growing up).
Gay conversion therapy. Now this one is different as many states are finally stepping up but many are not. We are allowed to essentially torture people because they don't fit a religious definition of acceptable. Medical exemptions such as those with blood transfusions and vaccines. these effect lives. These are just a few examples of the stuff we allow religion to get away with.
Now while this is a can of worms, I fully believe that there should be a line (or set of lines) that religion can't cross without legal repercussion. Basically when the religion can cause public or self harm, you should get in trouble. While it won't completely stop the problem, it will discourage con-artist pastors from engaging in misinformation campaigns and otherwise harming vulnerable people. It is fine to believe in Jesus or whoever and components of teachings but using the religion as a way to harm people is wrong. | Tax exempt status should not be determined by what anyone in the church **says** (this is debatable, and the whole bringing politics to the pulpit is another matter). Primarily though, it should be dependent on what they **do** with the tithing.
Other secular non profit organizations can get the same tax exempt status that churches do.
The difference is that non religious groups must open up their financial books to review by the IRS in order to get that tax exempt status.
Religions, on the other hand, get a "free pass". It's assumed outright that because they are a religion, they are doing good. And so, churches do NOT need to open up their financial books to the IRS.
That is what needs to change. If the churches want that tax exemption, demonstrate that they are actually doing good with the money. This would go a long way to weeding out the televangelists and the mega church pastors who collect tithes that go towards the "pastors" 2nd yacht, instead of going to help people, like it should. If the church actually is doing good with their income, fine, they can keep their tax exemption. We just need to level the playing field and eliminate these little "perks" that religious groups get without question.
| 51 | 107 |
ELI5: Why are employees expected to give a two week notice prior to leaving their job, whereas employers are able to terminate employees without notice? | Future employers are more likely to consider the bad feelings of a previous employer when considering a hiring decision rather than prospective employees being warned off by previous employees let go without notice. Power is not balanced in the relationship between employers and employees.
The two weeks is purely customary. | 18 | 15 |
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ELI5: How can some animals detect earthquakes before they happen? And why can't people? | Ey | Some animals can react to different frequencies which are outside the range of what humans can pick up. With earthquakes, you get extremely low frequencies generated by the earthquake which gets picked up by some animals before feeling the impact. It's like how dog whistles are high pitched enough so humans cant hear them but dogs can. | 15 | 50 |
Are most advancements in AI from better hardware or more advanced formulae? | Theoretically, a computer could brute force a problem to figure out every possible optimal solution, but that is absurdly infeasible in most instances, so systems use tricks such as classifiers and error minimization to get a "best guess."
When new milestones such as Deepmind's recent victories are reached, is this more due to faster processors allowing for deeper/wider searches with existing algorithms, or have the algorithms themselves improved? (I'm sure it's a little of column A and a little of column B, buy I'm asking for a little more specific than that) | Most of today's computer science theories were created way before the creation of efficient computers. But ANNs (Artificial Neural Networks) only began to be a research topic in the 1960s.
The new powerful hardware allows the researchers to think of new algorithms that previously seemed ridiculously inefficient, so it's a bit of both. Without good hardware, no one would bother to do ANNs, and without new theories, no amount of hardware would produce these results.
Also note the impact of the Internet : many ANNs are trained using massive amounts of data (especially ANNs that use images), and most modeln data storage and manipulation algorithms were created in the wake of the creation of the Internet. | 10 | 19 |
ELI5: What is so special/healthy about sea salt versus regular salt? | Sea salt is produced through evaporation of ocean water or water from saltwater lakes, usually with little processing. Depending on the water source, this leaves behind certain trace minerals and elements. The minerals add flavor and color to sea salt, which also comes in a variety of coarseness levels.
Table salt is typically mined from underground salt deposits. Table salt is more heavily processed to eliminate minerals and usually contains an additive to prevent clumping. Most table salt also has added iodine, an essential nutrient that helps maintain a healthy thyroid.
Sea salt and table salt have the same basic nutritional value, despite the fact that sea salt is often promoted as being healthier. Sea salt and table salt contain comparable amounts of sodium by weight. | 52 | 61 |
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Could someone explain the Alcubierre "warp drive" concept at a layman level? | There was an article posted over in /r/science, [this](http://news.yahoo.com/warp-drive-may-more-feasible-thought-scientists-161301109.html) one actually. However, I don't quite understand what I tried to look about the concept and how it works, and I fear that the article far oversimplifies what was said. | The general idea is such:
High-pressure space-time system behind, Low-pressure space time in front.
Normal space pressure immediately around/in the ship.
Your 'bubble' of normal space time is 'pushed' and 'pulled' along by the various 'pressure' systems. This way, the space-time bubble you are in is actually the thing moving, allowing you to exceed relative speeds of light.
Space-time surfing.
Disclaimer: Super-simplification, bad way to explain it, probably incorrect in all meaningful definitions of the term. Still, easiest way to visualize/think of it.
Wiki Summary:
>In 1994 Alcubierre proposed a way of changing the geometry of space by creating a wave which would cause the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship would then ride this wave inside a region of flat space known as a warp bubble, and would not move within this bubble, but instead be carried along as the region itself moves as a consequence of the actions of the drive.
Edit: Added wiki summary; made description more concise | 26 | 62 |
ELI5: Can someone please explain to me the "multiple comparisons fallacy?" | I want to understand it more thoroughly.
Note: A fallacy is an error in reasoning. | News reporting on science is hampered by the fact that most reporters are not trained scientists, largely because most scientists have jobs that pay more than all but a very few journalists.
When there are a bunch of scientific studies, a scientist knows there are many studies. To report that in the news, reporters want to tabulate them to make their story about 1-3 things rather than many because such stories are understood by many more readers. This tabulation, though easy to understand, is often a fallacy.
If reality is "Out of N studies, A produced result X and B produced result Y."
Tomorrow’s headlines read, “Studies show Y”. | 10 | 18 |
ELI5: If my bathroom scale shows different numbers around the house, which number should I trust? | **Didn't know if this was the right subreddit for my question, but here goes:**
I have a digital bathroom scale, and I know it works properly. Recently I moved into a new flat, and it's an old house, so all the floors are a bit wonky. I have no idea where it's even and where it's not.
**It shows numbers all the way up to 67,8 kg and all the way down to 65,0. Should I just find the mean number between all the results, or should I trust the highest? Or the lowest?** | Find something in your house that you know weighs a certain amount for sure. E.g. a new bag of rice or potatoes or whatever. Weigh that in different areas of your house and see where you get the most accurate reading. Just use your scale in that spot. | 16 | 15 |
CMV: Some Video Games Should be Revered as Much as Classical Art Displayed at Museums. | We're talkin' about a painting of a lady who can't decide whether she is smiling or not holding a place at a distinguished museum that people travel to witness its tiny fragile frame and yet there are entire worlds with storylines hashed out for several characters, physics engines, incredible details in some cases, and all of it can be interacted with by the audience on varying levels of immersion. Not to mention that pretty soon VR has the potential to upend some of the limitations that current levels of immersion present. | Museums exist to protect _singular_ artifacts and allow people to experience them. A video game (or anything digital, really) doesn't require protection because it can be perfectly duplicated an infinite number of times. You can't do that with a Picasso.
Moreover, what would the benefit be? You can't experience a video game in a museum setting - you have to play it to get the impact. Its the same reason that we don't have the original film reels of _Citizen Kane_ on display in a museum - you have to watch the movie to appreciate its importance. | 36 | 15 |
ELI5: I keep seeing studies that say vegetables have less nutrients compared to those 100 years ago. Does this apply to organic vegetables? Is there a way to ensure you’re getting nutritious food? | Yes, it also applies to organic... organic just means whether chemicals were used as pesticides or not. Many of today’s produce was selectively bred for longer shelf life, heartiness when being shipped long distances, often at expense of taste and nutrients. | 43 | 32 |
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Why aren’t underwater windmills more of a thing? | The way I reckon it, the tides go through multiple times a day in a predictable way. If turbines just sat there collecting energy 24/7 we’d get a lot of energy. You could put a nearly infinite amount of them up and down the coast line.
edit: thanks for all the reply’s | A few reasons,
1. Maintenance. It's very costly to maintain underwater infrastructure.
2. Corrosion is a big problem in salt water environments. Meaning more maintenance is needed.
3. Biological buildup. Again in saltwater, the blades are going to end up getting fouled by barnacles and other aquatic life making them less efficient over time... also needing more maintenance.
4. Limited useful locations - Tides are predictable, but you need to be in a place like a narrow bay inlet where the water actually flows inland and Outland. Out along most places on the coast, there's not actually a lot of tidal flow, just rising water. An ideal sort of location might be under the golden gate bridge. These high flow areas tend to be murky... complicating maintenance. That useful water flow also complicates maintenance because you can't easily service in high flow times.
5. Lastly transporting that power requires infrastructure either underwater or on the shore. In many of the ideal locations, placing that infrastructure is probably politically complicated.
Compared to wind turbines, the extra cost makes tidal systems less efficient over time. That's not to say there are no ideal places for it. It's just there are very few compared good wind production areas
Hydroelectric is more or less the same sort of thing mechanically, but you end up harvesting the potential energy from falling water flowing downhill. Frequently hydro project serves other purposes like flood control, fresh water collection, habitat and recreation. These other factors offset some of the higher capital and maintenance costs. It's also something that can be controlled and called upon in a time of need whereas a tidal system would be more like solar where it is predictable, but not controllable. Wind is neither predictable or controllable. | 146 | 79 |
What kinds of regular shapes will perfectly tile a sphere? | If you allow multiple shapes, the possibilities really are limitless, but if you want to use only a single shape, there is a simply mathematical property which helps understand what you can do.
Any way you tessellate will require a corner where at least three edges come together. Of course, on a flat surface, the sum of the angles where they come together have to add up to 360. When you are making a 3D shape, you'll need it to be less than 360 degrees, because they aren't lying flat. Well, a hexagon has interior angles of 120 degrees, and 3\*120 = 360. Thus, you can't possibly tessellate a 3D sphere with a hexagon- it must be with shapes of 5 sides or fewer.
| 38 | 39 |
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ELI5: Why do men start accumulating more stomach fat at around the same age range? | Generally, as people get older they become less active and eat the same amount of calories or more and therefore gain weight. Men tend to gain more weight around the stomach than other areas as opposed to women who tend to put on more weight on their legs etc.
While, there is some decrease in metabolism with age, its fairly small. The main culprit is lack of activity compared to youth. | 265 | 191 |
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ELI5: severed limb reattachment (e.g., which tissues in what order, success/fail factors, trauma-to-care time limits, etc.) | Med student here.
1) connect small vessels and nerves first, then the larger stuff like muscle. Better and easier to do it that way since otherwise you're working around big flesh pounds that are reconnected. So start with nerves and arteries/veins.
2) depends on what limb is severed but in general, the amount of time you have to get to a surgeon is about 4-5 hours. At the 5-6 hour mark tissue starts to die. The reason why reattachment is possible is because of this fact that limbs can survive detached for hours.
3) if you're going to transport a limb to a hospital, put it in a cooler. Don't put it in ice water, don't get it wet, keep it cool but not frozen. If it's a finger or toe, don't put it in your mouth, the bacteria fucks the digit up. | 48 | 241 |
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ELI5: Why do so many people who emigrate from the Middle East open convenience stores? | Each culture has an 'in' to a particular business in each area. So, one Korean family will come and open a dry cleaning business. When their cousins come, they will tell them the tricks of the trade and the regulations and have the business model set, so their cousins open up another cleaning business one town over - repeat for friends and family. Same with Indian people and small grocery stores or liquor shops, middle eastern immigrants and convenience stores. They share the business model within the culture and are immensely successful this way. | 31 | 24 |
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ELI5: Why are artists now able to create "photo realistic" paintings and pencil drawing that totally blow classic painters, like Rembrandt and Da Vinci, out of the water in terms of detail and realism? | Don't get me wrong, I find many of the classic works amazingly beautiful, I'm just trying to figure out why the old masters were not able to create art with the same level of detail and realism as what can be found in this album: http://imgur.com/a/3Bqjx#0 | Contemporary artists have a lot of advantages over classical artists. They have a better variety of tools and media, like airbrush, and higher quality paint. They have an additional 500 years of art history to work from, during which other artists have done a lot of work and developed a lot of new techniques. Also, they have photos to work from, and aren't constrained to live subjects. So, they can spend a lot of time looking at that reflection up close and seeing exactly what the shapes and colors are. | 4,339 | 3,655 |
ELI5: Why do we have to cook food in the oven for 20 minutes, but we can cook it in the microwave for 3 minutes? | Different types of energy. Convection is limited by diffusion. Microwaves have far greater depth of penetration and spin all of the water molecules in food. The resulting kinetic energy of the spinning molecules gives off heat. | 16 | 30 |
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ELI5: What would happen if a syringe of water was injected into your veins? | Say you were prepping for surgery, what would happen if instead of anaesthetic, you were injected with water, in both small quantities and say a syringe full or more? | If plain water were injected into a vein it would dilute the contents of the plasma (mainly electrolytes like sodium and chloride, and proteins) in that local area. Through a process called osmosis a portion of the water would fairly rapidly be drawn into nearby cells, in particular the red blood cells. Many of these cells would expand in volume rapidly to the point that their cell membranes would rupture, spilling their contents into the circulation.
For a very small amount of water there would be no lasting harm. As the amount increases more red cells would be damaged. The harm from this falls into two categories - as you lose red blood cells, your blood is less able to carry oxygen to other parts of the body, and the substances leaking from the injured cells would in large enough quantities cause harm themselves since the balance of what is kept inside and outside of these cells is delicate and well regulated.
If, instead of plain water, water with solutes in roughly the same concentration as the plasma was introduced (such as "normal saline"), and the quantities were not ridiculous, then it would simply become part of your circulating blood volume. Over time the extra fluid would end up dividing between your circulating blood volume, the insides of various cells, and the fluid that surrounds cells in your body outside of the circulation. This scenario is common - for example, small volumes of saline are usually used to flush medications given through an intravenous line in order to make sure all of it enters the blood at the time it was intended to be given. | 93 | 144 |
Why do so many chemical compounds manifest as clear, colorless liquids or white powders? | Even though there are millions of chemical compounds, it seems like only a few of them have an easily identifiable color (like copper chloride or the vapor of iodine) while the vast majority seem to be clear liquids (hydrochloric acid in water) or some sort of white powder (caffeine, ZnO, titanium dioxide). Why is colorless liquid or white powder the 'default' for most chemical compounds? | Color is based off the absorption of radiation in the ultraviolet-visible region (200-800ish nm wavelength). Since this is a sliver in the wavelength spectra, not many compounds have the necessary "chromophores". The most common are conjugated double bond systems, though metals of certain oxidation states absorb in this region. | 564 | 979 |
Can you be colorblind in just one eye? | I suppose what I'm getting at is - is colorblindness a disease of the eye or of the brain? Or of some stage in between? | Colorblindness affects the color receptors in the retina, and is genetic. So to be colorblind in just one eye would require something very unusual such as chimerism (where one person has multiple genomes in different parts of their body) | 169 | 316 |
CMV: Evidence is the only thing that should be allowed steer policy. It should be regarded as absolutely holy and should supercede any other forces dictating the architecture of our society. | I have always wondered how it is that anything apart from reason, logic and evidence has survived political debate. If one has reproducable, transparent evidence of some policy innovation leading to a decrease in suffering or an increase of human welbeing, how can one lose any debate that scores reason and scientific substantiation?
When presenting evidence and demanding evidence of the claims of the opposing party, one has instantly won when the opposing group lacks substantiation or am I missing something. How do we still allow disproven nonsense, guessing, unprovable supernatural beliefs and other things for which there simply cannot be any evidence provided, affect our society?
In a free society, I would think it vital to allow everyone their personal freedom as long as it doesn't affect others. But with something like the anti-vaxxing movement, society can't just accept their unsubstantiated claims affecting innoscent people. After presenting all the evidence and completing the debate of reason, these people have got to be, in the most friendly and civil ways possible, stripped of their capacity to hurt society, right?
Same story with religious or ideological extremism, including materialism.
Reason should prevail always, and the reasonable should claim/ have the right to suppress everything unreasonable when it comes to public policy.
Please change my maybe naive view.
Thaanks | > If one has reproducable, transparent evidence of some policy innovation leading to a decrease in suffering or an increase of human welbeing, how can one lose any debate that scores reason and scientific substantiation?
How do you define and objectively measure those? Let's say that single-payer healthcare is untenable. You can have that policy now and help people now, but causes major problems in the future. Alternatively, you could have a different policy that hurts some people now but ends up as a better solution in the long term. This is a hypothetical, not an endorsement of any current proposals.
There is also the problem of predicting the future. Two different groups can come to different conclusions based on their models of society. The world is constantly changing, and similar things from the past aren't guaranteed to work today.
> But with something like the anti-vaxxing movement, society can't just accept their unsubstantiated claims affecting innoscent people.
That's a slippery slope to go down. How much risk to society is acceptable? If you happen to get the flu, should you be quarantined to prevent transmission? Insults and unkind words sometimes lead to suicide; should that be banned? Most of the things we do affect other people. Where does it end? | 22 | 82 |
When they measure the distance between objects like planets and suns, at what point do they start the measurement? | Do they start at the center of the planet and how do they handle elliptical orbits? | It depends on the application. Typically in the solar system, we do it between the centers of mass of objects. This is good for figuring out where planets will be if you want to send a lander to them, for example, but then you really care about where the lander will actually land and so you also need a measurement of surface feature to surface feature.
For objects like stars, we don't know their distance precisely enough to care about the difference between start the measurement at the Earth or the Sun. And any ellipticity, while we can measure that because we can see the relative distances change or the position on the sky change, don't affect the overall measured distance, again because the errors on the absolute distance are so large. | 15 | 22 |
[Alien] For a universe with sentient androids indistinguishable from humans, long-term space travel, and off-world colonies; why do computers in the far future look so primitive compared to computers in 2020? | Reliability and ease of manufacturing.
Energy is cheap and plentiful, and ships built by the lowest bidder have an operational lifespan measured in centuries. Things are built so that they will function continuously for *decades*, without regular maintenance or human intervention. | 45 | 23 |
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ELI5 - In DNA there are four molecules that combine in the double helix a bajillion times to create you. Since they come in pairs, how is there so much variety to life? There's only four options - this pair, or that one, flipped this or that way. | Is there a certain amount of these four combinations that then become a "set"? | Same way a computer program is just 0 and 1, yea, not many options, but if you combine it enough you can get as many combinations as you need, just needs to be long enough. Because of that, it's essentially the length that determines the complexity.
As for a set, yes, DNA has start and stop codons, essentially a protein is defined by the stuff between a start and stop codon. Since the ends are marked, proteins can be as long as they need to be. | 28 | 15 |
Kant's Left Hand Thing | Hey, guys, I'm kind of an amateur student of philosophy, just getting myself started. I picked up a book that's an introduction to important philosophical ideas, and I found myself on one that I just don't understand.
The page called it "Kant's Left Hand" and it was about Kant's answer to an argument between Leibniz and Newton about space. Newton was arguing that space is laid out on a grid, and that if all of the particles in space were moved, space would be different. Leibniz, on the other hand, was saying that space's coordinates are only things as they relate to on another. So Kant came up with a thought experiment where he imagined a universe with only a left hand, and a universe with only a right hand, and drew the conclusion that Newton was right.
So... What's going on with this? I'm seriously confused about all of it, and especially in how Kant was able to solve it with an experiment that I don't feel proved a single thing. | You're on the right track here, but your characterizations of Leibniz, Newton, and Kant are all a little off.
The dispute between Newton and Leibniz had to do with whether space was something independent of the objects located and situated in space. Newton said yes, and the theory articulated in his *Principia* both required and defended this position. He thought that locations in space are absolute, and they are exactly where they are independently of where ever objects might happen to be in space. Google his famous "spinning bucket" thought experiment for more details on this.
Leibniz held a relationalist theory of space, and he said that positions in space were mere relations between objects. There are no facts about space independently of there being spatial objects with spatial relation to each other.
To get a sense of where their disagreement lies, imagine the following scenario: Every single object in the universe is suddenly moved 5 inches to the left. According to Newton, a real change has occurred, because now everything is in a different position. According to Leibniz, no change has occurred at all, because the relation between all objects remains exactly the same as it had been before.
Here's where Kant comes in. His argument is really just against Leibniz, not pro Newton. The main thrust of Leibniz's argument for relationalism was that spatial relations can only be cashed out in *conceptual* terms. That is, one can describe all spatial relations in terms of concepts like, "is 5 feet from", "is above", etc. Kant showed that mere conceptual relations cannot capture all there is to spatial relations. The two gloves example demonstrates this. If you take a right-handed glove and a left-handed glove, all the relations between the various parts of the 2 gloves are the exact same. For instance, the tip of the thumb is 2 inches from the tip of the middle finger, whether you are considering the left or the right glove. And if you describe each and every relation between the various parts of any one glove to all the other parts of that glove, then the set of relations you come up with for the left-handed glove will be the exact same as what you come up with for the right-handed glove. But if Leibniz's theory were correct, this would mean that the right and left gloves were exactly identical. But that's obviously not correct. There is something undeniably different between a left and right glove. This means, at least according to the Kant of the 1780s (he used the thought experiment for different purposes in earlier parts of his career), that space is not merely a set of relations between objects, but must have a status above and beyond that. So suck it Leibniz. | 23 | 25 |
What does Ricoeur mean when he says: understanding takes place in a non-psychological and properly semantic space? | It is important to note in this section of the present work (*Interpretation Theory: Discourse and the Surplus of Meaning*) that Ricoeur is contesting the psychologizing interpretation of Romantic hermeneutics such as one sees in Schleiermacher, who proposed that a reader must understand an author better than the author understood herself – in other words, Ricoeur is challenging the idea that one must gain a God's eye view into the author's mind in order to extricate the meaning of a text, which, in this view, is equated with 'authorial intention.'
It might be helpful to set your quote within its immediate context:
>"In conclusion, then, there is a problem of interpretation not so much because of the incommunicability of the psychic experience of the author, but because of the very verbal intention of the text. The surpassing of the intention by the meaning signifies precisely that **understanding takes place in a nonpsychological and properly semantical space**, which the text has carved out by severing itself from the mental intention of its author."
(*Interpretation Theory*, 76)
The intention of the author – the 'psychological space' – is irretrievable in any absolute sense, hence one works with the relative "semantic space" which is "carved out" in the form of a text.
Ricoeur does propose that historical-critical data do aid in interpretation – by narrowing down the possible range of meanings – yet he does not believe that authorial intention – to the extent that the reader may grasp it in any relative sense – closes the interpretation of any given text; the simple fact of the existence of the text, its being set in graphic (rather than spoken) semantics, opens it up to other possible interpretations. The possible range of meanings of a text, while both opened up and limited through historical-critical analyses, are not the exclusive property of authorial intention. | 13 | 23 |
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ELI5: Why are green flowers so rare in nature, and when they are, why aren't they as bright and vibrent and some other colours? | While there are some flowers that are green, they look almost white. So why isn't like a day-glow green? | The point of flowers is to attract the attention of pollinators. So they need to stand out from the plant.
The best way to do this is to have some contrast between flower and plant. Since clorophyll is the best way to produce energy, anything with a similar color is going to be ineffective.
Most flowers that are green were bred for that color | 23 | 15 |
Subsets and Splits