Giant magnetic ropes seen in Whale Galaxy's halo - <AUTHOR> https://phys.org/news/2019-12-giant-magnetic-ropes-whale-galaxy.html <comment><USER2> It's pretty cool they've been able to discover and image galactic Birkeland currents. Alfvén's work predicted that such things exist and, sadly, he didn't live long enough to see today's cosmologists continue his work.

</comment><comment><USER3> How do they get an image of the magnetic fields?

<comment><USER4> By measuring polarization of the received radio-frequency signals. The polarization is affected by magnetic fields ("Faraday rotation", see [0, 1]).

[0] [https://en.wikipedia.org/wiki/Faraday_effect#In_the_interste...](https://en.wikipedia.org/wiki/Faraday_effect#In_the_interstellar_medium)

[1] [https://www.mpifr- bonn.mpg.de/research/fundamental/cosmag](https://www.mpifr- bonn.mpg.de/research/fundamental/cosmag)

</comment></comment><comment><USER5> What does this mean for the long term evolution of galaxies, no need for dark matter?

<comment><USER6> No. The forces on stars from galactic magnetic fields are insignificantly small.

</comment></comment><comment><USER7> Strong magnetic fields in galaxies are very common. [http://scholarpedia.org/article/Galactic_magnetic_fields](http://scholarpedia.org/article/Galactic_magnetic_fields)

But there is a huge problem with them. Like Alfven, I am against the idea of frozen magnetic fields. Frozen fields were invented to explain how magnetic fields can exist, without the need for electric currents. At that time they thought that space was a very good isolator. Thanks to laboratories and satellites we now know different.

With my background in electromagnetism, I have to go one step further: frozen fields are physically impossible. The papers and text-books about them show false usage of induction laws. As if magnetism behaves like a current, like in a waveguide with electromagnetic waves. Sadly this is completely false. Induction in gasses or plasma behave a bit like those in a fluid, and they disperse the magnetic field. A bit like eddy currents. That is also what we see in our laboratories.

But magnetic fields can easily be caused by electric currents instead, because any electric current creates a magnetic field. This field is stronger when we measure closer to the current. So we can get very strong magnetic fields as we see inside young galaxies. Link: [https://www.discovermagazine.com/the- sciences/weirdly-strong...](https://www.discovermagazine.com/the- sciences/weirdly-strong-magnetic-field-in-young-galaxy-perplexes-astronomers) So we have electric plasma currents, instead of "magnetic ropes". Like in our laboratories. But I am not sure whether the community is ready to accept that..

Instead of the dynamo model, strong electric currents can easily come from nuclear explosions. These have been reported, but due to the secrecy they are not openly reported. Just a magnetic field can create a homopolar dynamo in an electric current. Currents are usually circular, but in a large space and very high speeds, the charge can take a long time to come around. It will be very interesting to actually measure the scale at which these occur.

Now if we have a black-hole like object in the centre of a galaxy, that spews out matter into 2 main directions. Because it also has a magnetic field, it is very likely that this matter has a certain charge. So this creates a current in the galaxy, which also generates the magnetic field. This how I think the magnetic field is generated.

The strength of these electric currents is in the order of 1/R, where R is the distance travelled. That is because currents are usually concentrated into one direction, like lightning, and only resistance hinders it. Magnetic objects encounter a force of 1/R^4 because magnetic objects have 2 poles. So these electric currents can transfer energy over very long distances.

As this matter-beam reaches the edge of the galaxy, it will turn around and go back to the galaxy. And because it has some charge, it will create a polarizing field in the halo.It would be interesting to see if there is also some sustained charge in these halos.

[https://fermi.gsfc.nasa.gov/science/constellations/pages/bub...](https://fermi.gsfc.nasa.gov/science/constellations/pages/bubbles.html) I suspect that the Fermi bubbles might have an opposite charge.

</comment><comment><USER8> This is no surprise if you follow the wave of evidence for the electrical universe model. It puts electricity and magnetism as the main shaping force of the universe while considering gravity a negligible influence.

Look on youtube. Lots of good material.

<comment><USER9> Look... the are bunch of us here who recieved a scientific training. While we don't claim that science can explain _everything_ at the moment, we do claim that there are a lot of crackpots out there with appealing ideas but zero capability of explaining them in a credible fashion.

For some reason these crackpot theories appeal to people who feel for one reason or other that they are "missing something". Then charismatic personalities gravitate towards these communities and spin out yarn that feels right to the specific people listening to them creating a belief. _Feels right_ and _belief_ are the keywords here. There is no proof that would withstand rigorous criticism.

With science, you should love your pet theory, put also put the hard labour in to prove it. And if your testing creates evidence to the contrary, you should be cognitively able to abandon it.

These crackpot theorists start from their pet theory, don't actually study physics or what ever their theory is about, and spend all the effort in spinning yarn about how great their theory is, instead of actually proving it.

If you want to learn about actual physics, there is great introduction lecture series by Leaonard Susskind called "The theoretical minimum":

[https://www.youtube.com/playlist?list=PL47F408D36D4CF129](https://www.youtube.com/playlist?list=PL47F408D36D4CF129)

Grab a pencil and paper and start watching :) !

<comment><USER10> I'm not sure I understand what you're trying to say... that you have put in the effort and you are confident in your analysis that this "electrical universe" hypothesis is not well formed?

I think it's a bit disingenuous to give a long, vague treatise on crackpots in response to an actual human being, without directly addressing them.

<comment><USER11> I "recieved [sic] a scientific training" as well, and I choose not to call people names for trying out new ideas. Given the state of cosmology these days, all the questions and recent and unexplained phenomena, an open mind towards new hypotheses (yes, _and_ encouraging following them up with tests ... in a non-snide way) is important.

"The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge, and there's no place for it in the endeavor of science. We do not know beforehand where fundamental insights will arise from.... Fundamental insights can arise from the most unexpected sources." \- Sagan

<comment><USER12> There is an ocean of difference between being open to new ideas and just letting any new concept get your equal mindshare without a compelling reason like evidence.

There is a reason no one that is respected talks about these "crackpot" ideas. The established ideas are here because they survived decades of trying to be proved wrong but they survive since they fit observed nature. New ideas are just that: new.

When someone introduces a new type of database HN doesn't say "why won't people take new ideas with an open mind??", they say "SQL works and has been proven. You have to prove your new idea is better before I'll use it."

Exact same concept.</comment></comment></comment></comment></comment>


The Student as Nigger - <AUTHOR> http://www.soilandhealth.org/03sov/0303critic/030301studentasnigger.html <comment><USER2> What the fuck happened to writing like this? When did rebels stop being incendiary? At what point did we collectively decide that we would rather gossip and titillate and flatter the reader? Whatever happened to the essay as hand-grenade? Why isn't anyone angry anymore?

</comment><comment><AUTHOR> This essay is particularly on my mind after writing about "The Validity of Grades" at <http://jseliger.com/2010/02/17/the-validity-of-grades> .</comment>


Ask HN: What is/was your most ambitious startup/product/service idea? - <AUTHOR>

<comment><USER2> My ultimate goal in my professional life is to create a system of virtual worlds that are more 'livable' than the real world. My obsession with this thought started when I read the Pendragon series years back, and it was reawakened by the anime series called Sword Art Online. All drama aside, I would love for people to be able to create their ideal world. Truthfully, if such a daunting task came to fruition someday, there would be a lot of problems to deal with.

The Oculus Rift project seems to be the closest (yet still incredibly behind) concept to my ideal MVP for what I would hope for this to be.

tl;dr Create a system of virtual worlds as portrayed in Sword Art Online

<comment><AUTHOR> Awesome idea tagabek. Thanks for sharing</comment></comment>


Why Can't We Get an Accurate Battery Life Test for Laptops? - <AUTHOR> http://bits.blogs.nytimes.com/2009/06/17/why-cant-we-get-an-accurate-battery-life-test-for-laptops/?hp <comment><USER2> At the end of the day, you need a 3rd party to perform benchmark tests and publish the data. It's not necessary for the manufacturers to do it, as long as it's available. The 3rd party in question could sell their data to CNET, etc., as an income stream.

An industry standard test that each manufacturer runs themselves is too hard for a computer. Too many variables. For example, the FTC has a test for speaker manufacturers to measure speaker power. What do I define as full power? I can make the speakers go really, really loud, but they sound terrible. Where do I take my power measurement? The FTC defined 10% THD+N as the max distortion allowed, so your power measurement was how much RMS power you could produce at 10% THD. However, what happens if you have a subwoofer and satellites? How do you get them all to max power at the same time, since for high frequencies, the woofer isn't doing anything, and for low frequencies, the satellites aren't doing anything. Well, you mess around until you find that magic frequency at your cross-over point where both sats and sub are at 10% THD. OK, fine, but when do you measure the power? As things heat up, amplifiers and wire and speaker coils get higher resistance, which lowers your output power. Somebody wanting to game the system could take their measurements quickly, while everything was cold. OK fine, the FTC set forth that the system had to have been running for 10 minutes at full power, before measurements are taken.

So, this is just for a lowly speaker system, and we've had to go through all of this. This is the test that the manufacturers run themselves and advertise their product with. Even with all this, there are companies that don't play by the rules. They give instantaneous power, peak power, or some other crazy power that they dreamed up over sushi and sake. Many don't bother to even list a power rating of any sort. Bose comes to mind, but there are others. Apple didn't do this either, perhaps they do now.

So, now for computers, imagine how difficult it would be, when you have variable wifi power, transmission bandwidth, distance from router, router power, variable monitor brightness, display resolution, refresh rates, variable hard drive access profiles, variable CPU loading profiles, etc. There's no way you can trust the manufacturers to not game a system so complex.

Get a 3rd party to do it and publish it.

<comment><USER3> A 3rd party IS doing it and they do distribute their reports. Consumer Reports has been doing testing like this on a variety of stuff for over _70 years_. They don't take outside advertising or free samples to avoid bias. Their tests have held up in court as valid. They're really good.

Next time you see a sketchy battery life claim by Apple [1], Acer [2], or anyone else, just take a glance to see if Consumer Reports has said anything about it. I'm not asking for you to take their word for granted, just consider it the opinion of a reputable 3rd party.

[1] Testing MacBook Pro's 8-hour battery life [http://blogs.consumerreports.org/electronics/2009/04/testing...](http://blogs.consumerreports.org/electronics/2009/04/testing- macbook-pros-8hour-battery-life.html)

[2] Acer laptop claims 8-hour battery life [http://blogs.consumerreports.org/electronics/2009/04/acer- la...](http://blogs.consumerreports.org/electronics/2009/04/acer-laptop- claims-8hour-battery-life.html)

<comment><USER2> Yep, they do it. But they don't, apparently do it enough to please AMD.

Having somebody decide to test some random product when the feeling strikes them, is different from somebody who is religiously testing all available products creating a database where all the data fields are the same, all the test conditions are the same, etc.

</comment></comment></comment><comment><USER4> I've found the Apple laptops to be closer to the actual stated times more than any other manufacturer. But I guess this is more to do with the test suites available (none for Mac). Some manufacturers are notorious (hmmph Acer) for gaming results by reducing screen brightness to 20%, running the proc at the lowest level, disabling Wifi and not much else. Basically letting the laptop sit there until the battery runs out.

I called technical support about this because I was getting ~45 minutes even though the box stated 2.5 hours. What I was doing (web browsing over wi-fi, in the late afternoon) would get me the reported time. Seriously, the only way I was going to get 2 hours would be by sitting in the dark with no internet connection using notepad.

</comment><comment><USER5> From a Electrical Engineering standpoint, any battery of tests will not hold up due to the amount of variables, both software and hardware. The article references iPhone as a perfect case, but Apple (and AT&T, indirectly) have 100% control on what occurs on the device. The software, hardware, and user flow is under strict standards of processing and memory allocation. Furthermore, the low processing power and subsequent need makes the margin-of- error and standard deviation lower.

This is not the case for laptops. Due to running different programs, there are differing memory and processing allocations which cause different hardware elements to be accessed. Chrome and Firefox (same use case) have vastly different memory footprints and certain versions of Photoshop (same program) will utilize the GPU, increasing current drain. Since programs are constantly under development and will use different amounts of resources, a manufacturer cannot say that browsing the internet or using a specific program will be a certain amount of time.

Mainstream laptop batteries are Lithium-Ion, which degrades with time (faster with use). Unless retailers begin to throw out older batteries (by manufacturing date), there will be no standardization for consumers.

</comment><comment><USER6> Most PC manufacturers might use MobileMark, but Apple tests with 50% brightness, Wifi on browsing "various websites" and editing text in a word processor. Even other than the iPhone, Apple seems to do better than other manufacturers at battery testing and disclosure.

<http://www.apple.com/macbookpro/specs.html> #5 on the bottom of the page as the source for this information.</comment>


Paradoxes That Threaten to Tear Modern Cosmology Apart - <AUTHOR> https://medium.com/the-physics-arxiv-blog/the-paradoxes-that-threaten-to-tear-modern-cosmology-apart-d334a7fcfdb6 <comment><USER3> > What's more, there is an energy associated with any given volume of the > universe. If that volume increases, the inescapable conclusion is that this > energy must increase as well. And yet physicists generally think that energy > creation is forbidden.

It's important to remember that energy conservation is not an axiom of basic physics. It is a consequence of Noether's theorem and temporal symmetry in the laws of physics. In the framework of GR, this means that any static metric will have some conserved quantity that corresponds to energy (though, in general, it will not be the same as the Newtonian energy). But if the metric is not static (as in the case of an expanding universe), there is no need for energy to be conserved.

<comment><USER4> Tangential side question:

Must energy conservation be local? Would it be "legal" for -- say -- energy to be spent/dissipated (entropy increase) at one location leading to an apparent over-unity effect ("free" entropy decrease) somewhere else? I'm not talking about energy transmission through wires or EM radiation... I mean something apparently disconnected yet coupled.

I ask because I've encountered such ideas in sci-fi before and couldn't think of a reason why they're forbidden -- though I have no idea how you would do such a thing.

<comment><USER5> If it's coupled, wouldn't it cross the boundary of the system, and then be included in normal entropy calculations as a flow across the boundary?

<comment><USER4> Exactly... just wondering if energy had to be conserved locally or globally?

Let me give you an example scenario:

Let's say (ignore the mechanism for now) that it's possible to send a small amount of information from point A to B. This information takes a tremendous amount of energy to generate at point A, and when it's received at point B it can be used to (somehow) unlock a tremendous release of energy. If you only looked at point B, it would look like you had an "over-unity device." But in reality the energy spewing out at point B is paid for at point A, and the information transfer by occurring at the speed of light does not violate causality.

Not claiming it's _possible_ , just asking if it's expressly forbidden by fundamental physics or not.

(If it _were_ possible it would of course open up all kinds of very amazing things like remotely powered space propulsion, a whole next level of power grid technology, or orbital solar power that actually worked, but I know of no effect that accomplishes anything like this so it's total sci-fi even if not forbidden by any known law.)

Edit: according to another response this likely is not possible. Oh well. :)

</comment></comment></comment></comment><comment><USER6> I believe there are important social aspects of why/how the large public is presented with certainty about what Science says and has discovered while behind the scene things are not that pretty. It seems that we too often forget that all of our beliefs are based on assumptions, some tested some not, some testable and some not. This means that our efforts are always asymptotically growing towards having true knowledge, as in a true justified belief. This should force some sense of humility in us, specially when dealing to others' beliefs. Religious or not.

<comment><USER7> Science isn't about "beliefs".Science is about facts.Science isn't afraid of the unknown or to be challenged. Religion says one will rot in hell(whatever it is) if one challenges religion. There is no knowledge in religion, as religion doesn't explain anything that can be experimented by man kind.It's just failed philosophy, and it's pretty arrogant. But you're right,both religion and science are man made,they just have 2 opposite purposes.

<comment><USER6> There are many fields in Science. It's one thing to say if we build this bridge this way it will resist to an earthquake of this magnitude, and another thing to say x years ago there was a population of humanoids that did this and that. In the second case our explanation (composed of a set of sentences which are beliefs to be proved as true) is constructed by inferences from our observations (facts): this tool, that wall painting, whatever.

<comment><USER7> > It's one thing to say if we build this bridge this way it will resist to an > earthquake of this magnitude, and another thing to say x years ago there was > a population of humanoids that did this and that.

that's not a belief.You can experiment and reproduce that experiment.Whether you get all the variables right is the issue science deals with.

You can't "experiment" god,heaven,hell or angels.These are fairy tales which are based on nothing but ignorance.Their only purpose is power and control. Religion is useless. If you crave for spirituality,then philosophy is a better alternative.

</comment></comment></comment></comment><comment><USER8> I've always thought that what we don't know is larger than what we do know, except that we can't measure what we don't know. The universe is continuously surprising. Each discovery winds up trumping the supposed status quo. Being a cosmologist must be a lot like being a javascript programmer, every day what you thought you knew is now obsolete.

<comment><USER9> > we can't measure what we don't know.

This is interestingly put, and I would not completely agree with it. Let med give two examples:

1\. Before Quantum mechanics we could measure the Photoelectric effect (that is, light that is energetic enough can shoot off electrons from metal plates). This is a Quantum phenomena, and we could measure it before the theory was discovered.

2\. Before General relativity we could measure the precision of the elliptical orbit of Mercury. This could not be explained by Newtonian gravity, and is a relativistic effect. But could be measured before the theory was discovered.

And before these; Electric eels can shock you, and Magnetic rocks still attract each other, even before Maxwell, Ampere, or Coulomb were even born.

The problem now a days (for fundamental theoretical physics) is that we are mostly put in the categories: * There is no data we can't explain with theory. * Theory that is consistent with current data and only predicts new features at much higher energies than we can design experiments for.

There are some exceptions to these, but I will exclude these for now, since they are a bit technical. Example of the first one: There is no data directly implying a quantum nature of gravity [1]. Example of the second one: Supersymmetry might not be visible at LHC because LHC is too weak.

That second category is why people jump on new results directly, like the BICEP or the super-luminal neutrinos, and the hep-th/ section of arxiv.org is flooded with papers trying to explain it. However, for both these cases, the measurements turned out be be wrong.

> every day what you thought you knew is now obsolete.

This is what many people say, but I would not agree (in fundamental physics). For example:

* One can say Newtonian mechanics is wrong because we have Special relativity now. But one should say: There is a regime (high velocities) in which Newtonian mechanics breaks down. This regime is determined by the speed of light, c. Newtonian mechanics is still correct for velocities much smaller than c. * One can say that Quantum mechanics makes Newtonian mechanics wrong. But one should say: There is a regime where Newtonian mechanics breaks down and Quantum mechanics governs, which is determined by the Planck constant.

and so on. It is not "obsolete", or have not turned out to be wrong. One only needs to append new aspects in various regimes.

[1] See e.g. [http://backreaction.blogspot.fr/2013/11/big-data-meets- eye.h...](http://backreaction.blogspot.fr/2013/11/big-data-meets-eye.html) > Those of us working on the phenomenology of quantum gravity would be happy if we had data at all [...]

<comment><USER10> Wikipedia's list of unsolved problems in physics [0] includes problems that aren't "no data we can't explain" and "we can't test it yet". They're more like "we expect that the theory can explain observation X, but we don't know how yet" and "we don't know what the theory predicts for situation Y". For example:

\- Mechanism for baryon asymmetry

\- Mechanism for ultra high energy cosmic rays

\- Mechanism of high temp superconductors

\- Black hole information paradox

\- Finding solutions to the Schrodinger equation in various situations

You might mean something very specific when you say "Fundamental physics" though.

0: [https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_p...](https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics)

<comment><USER9> Oh, I do simplify a lot and hide myself under "Fundamental physics". You are absolutely right to call me out on that. :-) But lets think about one of the examples that you brought up:

> \- Black hole information paradox

This is indeed a big question, but I would discard this in what I wrote since: What is the experiment here? There is theoretical evidence for the Black hole entropy, but even if we could create black holes, which has so far not been accomplished by the LHC, how would you measure it? It is a bit more difficult than a gas where you could deform it and measure temperature etc.

So this I would discard because I was considering discrepancies between theory and experiments.

> \- Mechanism for...

some of these I would exclude in what I wrote because they might be explained by current theories, but it is just not known how exactly. Take ultra high energy cosmic rays, there are Shock-front acceleration mechanisms, Supernovae explosions etc that are candidates, and if I understand the formation of that unsolved problem correctly it is to among these candidates identify the correct one or the main one (or if the candidate is not among the ones we know now, find a new one and explain it).

</comment></comment></comment></comment><comment><USER11> That article didn't even mention dark matter and dark energy. Those also "contradict basic physics" in the sense that they need to be conjured into existence to explain our observations.

<comment><USER9> It does actually. The statement:

"What's more, there is an energy associated with any given volume of the universe. If that volume increases, the inescapable conclusion is that this energy must increase as well. And yet physicists generally think that energy creation is forbidden."

is regarding vacuum energy = dark energy = cosmological constant, etc, and continues to discuss it after that.

Another thing I find annoying is when they (this article and also others I have seen linked here on HN) paint the picture of that breaking energy conservation is some kind of magic going on -- it is far from it.

In General relativity (GR) you can construct conserved quantities from Killing vectors [1]. For example, if you have a time-independent metric (the GR tool for measuring lengths in space-time) you get a time-like Killing vector, which is associated to a certain conserved quantity; Energy. (Another example is when the metric has certain angular independences and you get conservation of angular momentum.)

Now in metrics that mimics cosmological evolution (that is, evolution in time), you have to break time-independence, hence your time-like Killing vector is gone and your energy conservation law is gone!

This is portrayed as some magic-like thing (at least that is how it sounds to me when I read these popular cosmology articles), but it is simply a consequence of the mathematics of GR. It might break some usual physics intuition, but I would not say that physicists (at least in this field) are surprised by it.

So it does not really "contradict basic physics", one just needs to know more about the details to get a good view of it. We do not need to figure out (or "conjure into existence") a way to break conservation of energy (as is the example here), it is already there in GR.

[1] [https://en.wikipedia.org/wiki/Killing_vector_field#Geodesics](https://en.wikipedia.org/wiki/Killing_vector_field#Geodesics) The article on wikipedia is quite lacking on this point, but I link it here anyway.

<comment><USER12> Nicely put, though I'd point out

> _It might break some usual physics intuition,_

It really shouldn't in light of Noether's theorem: The fact that time independence of the action S gives rise to energy conservation in the first place tells us pretty clearly: If your action has time dependence, you don't have conservation of energy.

</comment></comment></comment><comment><USER13> > this change may be as much as one centimetre per second per year

Anyone have an idea what that's supposed to mean?

Edit: Ah, thanks to both of you, it seems obvious now

<comment><USER9> It has the unit-dimension the same of acceleration (that is [Length]/[Time]^2), so it should be read as:

'Every year, the velocity of the distant quasars (going away relative us) is increased by 1 cm/s.'

<comment><USER14> Could there be a similar observation of this if time were slowing slightly?

<comment><USER15> I don't see how. Also, what would "time slowing slightly" even mean? That is, what frame of reference is time slowing against? How would we even measure that effect, given that all of our tools which measure time do so my detecting a fixed interval of it passing? Intervals which would also be "slowed".

<comment><USER14> To be more specific, if our reference time were slowing slightly, where 'our' is defined as all humans and devices making the measurements.

<comment><USER16> I think our time would have to be slowing different amounts w.r.t. objects at different distances from us. This would imply a Universe-wide effect on the rate of passage of time which is coincidentally centered on Earth, or at least on our group of galaxies. Universal expansion has the advantage that it doesn't require the Earth to happen to be at a special privileged point in the cosmos.

</comment></comment></comment></comment></comment></comment><comment><USER17> I totally agree with you.

</comment><comment><USER18> I want to see a picture of the sun in the visible spectrum taken in free space or from the moon.

<comment><USER19> This is the sun right now: [http://sohowww.nascom.nasa.gov/data/realtime/hmi_igr/1024/la...](http://sohowww.nascom.nasa.gov/data/realtime/hmi_igr/1024/latest.jpg)

"The MDI (Michelson Doppler Imager) images shown here are taken in the continuum near the Ni I 6768 Angstrom line. The most prominent features are the sunspots. This is very much how the Sun looks like in the visible range of the spectrum (for example, looking at it using special 'eclipse' glasses: Remember, do not ever look directly at the Sun!). The magnetogram image shows the magnetic field in the solar photosphere, with black and white indicating opposite polarities. " from: [http://sohowww.nascom.nasa.gov/data/realtime/realtime- update...](http://sohowww.nascom.nasa.gov/data/realtime/realtime-update.html)

<comment><USER20> I'm trying to use [http://seal.nascom.nasa.gov/cgi- bin/gui_seal](http://seal.nascom.nasa.gov/cgi-bin/gui_seal) to get some of the recent images from that particular instrument, but can't figure it out - <USER2> results are returned for my search query: [http://i.imgur.com/ANlgBT4.png](http://i.imgur.com/ANlgBT4.png)

Anyone know what I'm doing wrong?

Edit: this might be a better resource, and can automatically show you an animated sequence: [http://sohodata.nascom.nasa.gov/cgi- bin/data_query](http://sohodata.nascom.nasa.gov/cgi-bin/data_query)

<comment><USER21> MDI is no longer operational. It operated from 1996-2010. So your query for 2015 comes up empty.

The successor instrument is called HMI, which returns 4096^2 images on a pretty fast cadence (45s or 720s depending on your purposes). It is much superior to MDI. The HMI instrument team is at Stanford University, so I'd point you there for data rather than to the NASA site, which offers a lot of sources and seems to suffer from a least-common-denominator effect.

Recent HMI quick look products are here: [http://jsoc.stanford.edu/data/hmi/images/latest/](http://jsoc.stanford.edu/data/hmi/images/latest/)

There is a back-catalog of JPEG images for browsing: [http://hmi.stanford.edu/data/hmiimage.html](http://hmi.stanford.edu/data/hmiimage.html)

For science purposes, you can get FITS data from [http://jsoc.stanford.edu](http://jsoc.stanford.edu) . There are a lot of data products -- intensity, magnetic field (line-of-sight and vector), velocity, tracked regions, etc., as well as near-real-time analogs of much of this data (not as well-calibrated, but arrives within a couple hours of being taken).

There is no embargo on this data. They just expect acknowledgement ([http://sdo.gsfc.nasa.gov/data/rules.php](http://sdo.gsfc.nasa.gov/data/rules.php)).

<comment><USER20> Thank you!

<comment><USER21> My pleasure. I developed a data product for both instruments.</comment></comment></comment></comment></comment></comment>


The most profitable small businesses - <AUTHOR> http://www.forbes.com/2010/04/15/most-profitable-small-businesses-entrepreneurs-finance-sageworks.html

<comment><AUTHOR> Not particularly inspiring for hacker types, unless you consider it a list of potential customers for whom to build tools. Most of the businesses listed require specialized skills or significant startup capital.</comment>


Google Analytics market share in the top 1m domains - <AUTHOR> http://metricmail.tumblr.com/post/904126172/google-analytics-market-share

<comment><USER2> A follow up article with a more in depth technical component would be nice to see as well. ;)

<comment><USER3> Yes, I'd love that too. Especially looking a penetration rate but more focused on top sites (i.e. 1-50K, 1-100K, etc.)

</comment></comment><comment><USER4> If the owner is reading this: Add a link to your product on the header of the blog. I wanted to know more about your company/product, but I was stuck in your tumblr blog.

</comment><comment><USER5> In case it's interesting to anyone else, here's a more trusted link to the Alexa and Quantcast top 1M sites lists:

[http://www.seobook.com/download-alexa- top-1-000-000-websites...](http://www.seobook.com/download-alexa- top-1-000-000-websites-free)

<comment><USER6> <http://www.alexa.com/topsites> -> <http://s3.amazonaws.com/alexa- static/top-1m.csv.zip></comment></comment>


Developing a better CMS - <AUTHOR> http://www.thinkvitamin.com/features/webapps/developing-a-better-cms

<comment><USER2> Can someone tell me what is ground breaking about their system?</comment>


Eyeballing Skill Test (Are you pixel perfect?) - <AUTHOR> http://woodgears.ca/eyeball

<comment><USER2> 3.85 in 313 seconds. Parallelograms were my worst with 19.5, 4.8 and 11.6 units off respectively. I had a couple perfects 0.0 which were on the line segments and splitting the angles. Also had a few under 1.0. I feel accomplished! Pretty fun little test.</comment>


New programming jargon you coined - <AUTHOR> http://stackoverflow.com/questions/2349378/new-programming-jargon-you-coined/2444303

<comment><USER2> Code Prion -

n. a really bad idea dressed-up as a good idea thereby becoming contagious in a way that never seems to die out.

n. memes adopted as a religion by the clueless because "it seems like a great idea" while drowning-out the opposition because the arguments against are subtle.

* "Our object model makes it hard to implement NaNs" -- famous last words before adding hundreds of if_special() checks to your code and transforming your object model into something that defeats your ability to reason about programs by undermining common notions of equality as being reflexive, symmetric, and transitive. If you doubt that identity-implies-equality, then you're infected.

* Most ideas for pre-commit hooks are code prions. If your process depends on crippling a developer's ability to make a check-in, then you're infected.

* "Our dynamic language doesn't implement static language feature X". If you think Ruby and Python need Enums and Interfaces, then you're infected. Those features cost nothing in compiled languages and often only serve to overcome the limitations of those languages.

* "We're making everything clean and pure by deprecating everything we don't like anymore." Hey, it only takes you ten minutes to add the deprecation, who cares if it consumes hundreds of hours of user-time to update their programs or if they stick with an old version just to avoid your deprecation hassles. Better to just document it as obsolete than to inflict pain on a large user base. (By the way, authors of books will hate you too -- it makes their books go out-of-date prematurely). If you think of published APIs as mutable, then you're infected.

* If you think self.assertLessEqual(x, y) is the right way to spell, "assert x<y", then you're infected. Get nose.py or py.test and live free.

* "Everybody knows eval() is an egregious security hole, so you should never use it." Learn to differentiate between trusted and untrusted code; otherwise, your fear will keep you from using your most basic and powerful tools. This code prion is chonic and progressive -- eventually you'll find yourself unable to write "import collections" because someone might have stolen you ssh key, logged into your machine and added their own collections.pyc file which would appear to run normally but actually emails your mother's secret porridge recipe to wikileaks. If you think eval() is evil, you're infected.

</comment><comment><USER3> I hate to write this... But I've seen a few of these "most upvoted" StackOverflow questions posted to HN in the last few days, and, although they are _good_ articles, they are _very easily accessed_ (by which I mean, all you have to do is go to StackOverflow and click on questions, and then on most voted; likely what anyone new to it would do. As programmers, I'm pretty sure _most_ us have visited SO at least _once_ ), and hence something most of us would have already seen.

People will see this phenomenon and it'll catch on, and HN will end up like Digg, with the only content posted being "top tens".

</comment><comment><USER4> Awesome...

"A Duck"

 _A feature added for no other reason than to draw management attention and be removed, thus avoiding unnecessary changes in other aspects of the product._

<comment><USER5> In Jewish folklore, this is I guess a hundred or two years old, and is called a goat or a sheep:

A man complains to his Rabbi that they have a tiny house and they can't manage with their wife and three kids all in the same room. The rabbi tells him "take your goat and put it in the room as well". The man does as advised, and comes back to the Rabbi two weeks later, complaining even more. The Rabbi tells him "take the goat out". The next time the man sees the Rabbi, he thanks him "We have so much room now that the goat is out".

</comment></comment><comment><USER6> I like the comment under "Refuctoring":

> We had a guy come in and immediately strip out comments and whitespace from > our code "to make it faster".

<comment><AUTHOR> Kent Beck mentioned this Refuctoring video a few months ago: [http://www.youtube.com/watch?v=7RJmoCWx4cE&feature=youtu...](http://www.youtube.com/watch?v=7RJmoCWx4cE&feature=youtu.be)

The author kept the tests green while refuctoring it...

</comment></comment><comment><USER7> A buddy and I coined SQL Ejaculation.

Where you use SQL to generate text to be executed by another system...like HTML.

Have you ever seen an entire web site generated by stored procedures. I have. It aint pretty.

</comment><comment><USER8> I recently coined (afaik):

        enbug - v. to program; the opposite of debug

<comment><USER9> Sorry to burst your bubble, but there exists enbug.org whose about page (<http://enbug.org/AboutThisSite>) says:

        The meaning of enbug is the opposite of the word debug, namely, to add errors or defects into software or hardware.

That page was last edited on 2007-03-04.

</comment></comment><comment><USER10> Hindenbug is pretty funny.

 _catastrophic data destroying bug - "Oh the humanity!"_

<comment><USER11> And its cousin, the Heisenbug [1]

full-disclosure: I didn't read the linked article, but can only assume that it's in there.

1 = <http://en.wikipedia.org/wiki/Heisenbug#Heisenbug>

</comment></comment><comment><USER12> Just a quick warning before you click through: pages and pages of puns.

<comment><USER13> dammit - warning came 2 hours too late.

</comment></comment><comment><USER14> Wrong is what with Yoda conditions?

<comment><USER15> Nothing wrong there is. To understand and read them quickly difficult it is.

Subject verb noun, to process, is easier.

<comment><USER16> For native speakers of English and other Subject-Verb-Object (SVO) languages, anyway; it sounds like a weird variant of passive voice. There are also SOV, VSO, etc. human languages, though.

<comment><USER17> Dakota has some combos that sound different to English speakers (e.g. phrase: "Mazaska wacin", Mazaska = money, wacin = 'I want').

// my choice of example phrase is based on what I valued as a teenager (and can still remember), not some weird social commentary

</comment></comment></comment></comment><comment><USER18> reverse polish hungarian notation: char * nameZspl;

ifless if: ptr && (* ptr = 10);

WTF-8: an almost-UTF-8 type of encoding, which possibly cannot be decoded anymore

gangbang of four: an act of cluelessly quoting GoF, Fowler et al.

</comment><comment><USER19> Favorites: Smug, Drug, Chug, and Shrug reports. Will have to remember those...</comment>


TrueCraft bans developer who have read reversed MineCraft code from development - <AUTHOR>

https://github.com/SirCmpwn/TrueCraft
"If you want to keep up with development or contribute, join #truecraft on irc.esper.net. Pull requests will be rejected from authors who have read any decompiled official Minecraft code.
To get started, sign the Contributor License Agreement to establish that you have not, in fact, ever read decompiled Minecraft code.
If you have read the Minecraft source, you can contribute to the TrueCraft wiki here. Under no circumstances should you expose clean devs to source code."
It seems like a draconian measure considering that a big part of people interested in TrueCraft development, could be programmers interested enough in MineCraft to have seen the code. I think that early modders were forced to reverse MineCraft in order to get the code to work. What do you think? <comment><USER2> [http://en.wikipedia.org/wiki/Clean_room_design](http://en.wikipedia.org/wiki/Clean_room_design)

They're taking a route that is intended to prevent legal challenges in the future. It makes quite a bit of sense.

</comment><comment><USER3> Hardly draconian. Since Truecraft describes itself as a clean room implementation it would be hypocritical to accept contributions from people who have read the code.

</comment><comment><USER4> The alternative is they risk Microsoft coming after them for stealing the intellectual property they just paid billions for.

<comment><USER5> Businesses aren't just buying into IP - they're buying into a brand, onboarding their engineers, absorbing the userbase.

On the flip side, maybe MS will be excited and flattered to see it's in C#. Maybe MS will take this as a new Minecraft codebase. If you're MS, why bother with java? How does an open source MC hurt? The bukkit community seems to be active :) [1]

[https://bukkit.org/](https://bukkit.org/)</comment></comment>


Unemployment by degrees  - <AUTHOR> http://www.economist.com/blogs/freeexchange/2011/02/americas_jobless_recovery_0

<comment><USER2> I was expecting a comparison between different college degrees, not high school vs college.

<comment><USER3> This would be actually interesting</comment></comment>


BitCannon – A torrent index archiving, browsing, and backup tool - <AUTHOR> http://bitcannon.io

<comment><USER2> A torrent index that I can view thru an emacs mode would be the most useful. If the data format is just a text tile with each torrent taking one line would be amazing. It would be long, but it's just text so memory consumption is negligible. Kinda same style as Org-mode, I imagine.

You could just search like usual, open a magnet with Return, click 'c' for it's comments. When opening the file, the mode would check for seeders/leechers and display it inline.

<comment><USER3> That's an interesting idea, and I'm sure people familiar with emacs would find it very useful. BitCannon has a pretty simple API (at least I think) so feel free to tinker around and make alternative clients for it!

</comment></comment><comment><USER4> Hi, excellent idea but each time I try to import a file, I've got file parsing ended. New: 0 Dup:xxxxxx. In the site, there is no torrent at all. It looks like the import works but think that it is already imported? I've got a Win8.1 64 bits and I tried the 64 and 32 bits .exe. I run the latest version of MongoDB 2.6. Any idea of what I'm doing wrong? Thanks!

</comment><comment><USER5> BitCannon Windows Guide with autostart script for the curious [http://www.htpcguides.com/install-bitcannon-personal- kickass...](http://www.htpcguides.com/install-bitcannon-personal- kickasstorrents-windows/)

</comment><comment><USER6> I would love if that was a desktop client. I don't want to mess with Mongo and Node for my own torrent index. Maybe I could persist the index on dropbox or something and point my client to it. NW.js seems like a good option for this!

<comment><USER3> I'm not using Node in the web app itself, just for dependency management and development. Once the app is built, it's just angular and regular js.

Give it a try, I think that will clear up any confusion. All you need is MongoDB and the BitCannon binary.

(ie You only need Go/Node/bower/grunt if you wish to compile it yourself)

</comment></comment><comment><USER7> This is an interesting concept because until reading this, it had never occurred to me that the torrent indexes are typically centralized as opposed to the decentralized nature of torrenting.

<comment><USER3> That was exactly my goal. I was thinking how easy it is for people to download the backups that a couple torrent sites provide, but hardly anybody does so because the backups are hard to use. I also hope that, in addition to encouraging people to download torrent archives, that I may also help encourage more torrent sites to provide archive downloads of their torrent database.

<comment><USER8> Would it be possible to populate it just by indexing everything tracked in DHT? There was a research paper featured here recently, but I can't find it right now. They had a way of getting a decent chunk of all the DHT torrents and did some analysis based on that data.

<comment><USER3> I think that would be a nice way to import torrents without relying on a site that could be taken down. Unfortunately, I don't know a ton about DHT and the BitTorrent protocols. I'm still trying to figure out how to scrape a UDP tracker in go to get seed / leech counts. I like this idea though!

</comment></comment></comment></comment><comment><USER9> So you have a NodeJs server for the web interface and a Martini server for the API part? Would it not have made more sense to have chosen either NodeJs or Martini for the whole project?

<comment><USER3> Initially it was separated, but I thought the same thing so I embedded the web app in the binary and Martini now serves the whole thing.

</comment></comment><comment><USER10> @Stephen304, what are the mechanisms for gathering index content?

Does the user manually download those from centralized sites?

How do the centralized sites get their index content?

<comment><USER3> Currently, users have to manually download archives from torrent sites that provide them (Kickass and Demonoid are 2 I know work with BitCannon)

I know this isn't ideal, so I intend to implement an auto updating function to periodically auto download and import updates. You can see the beginnings of this in the config file in the current release.

<comment><USER11> BitSnoop has a db of 24m+ torrents available, though it's (i) badly categorised and (ii) offline atm.

[http://bitsnoop.com/api.html](http://bitsnoop.com/api.html)

So if I installed this, I would (for the moment) currently need to grab the dump from KAT or Demonoid or wherever, extract it, and add it to the database...? How does it deal with duplicates from the same site - or the same infohash found on different sites?

<comment><USER3> Yes, that's the current process for importing torrents. Making an automatic import / update is high on my priorities.

It uses a unique key on the infohash, so it skips duplicates at the moment. I've thought about concatenating the categories info when duplicates are found, so a torrent on kickass in Movies and Demonoid in Anime will merge to be 1 torrent with [Movies, Anime], but it isn't too high on my priorities considering I still have to add a UDP tracker scraper.

<comment><USER11> Okay, so installed and added today's KAT db in.

A few initial thoughts: 1\. It took 2-3 hours to add in the whole KAT db. No problems in parsing the data from what I could tell, but a long time to do it. Maybe that's my machine but it's not ridiculously slow. I'm not going to be adding in the bitsnoop db of 24m+ torrents at this rate.

2\. Pulling up 'browse' takes 45-50s just with the KAT stuff indexed and it takes that long every time I click on browse. Could you add some kind of caching to that page?

3\. There's no paging. It loads a page of results and no more.

4\. Search is very very fast. Would be nice to be able to specific the category when searching.

The main thing it's missing that makes other sites good is all the ratings, seed/leech data, comments, meta data. I wondered, maybe you could do a large scrape of KAT every now and again that grabs all of that and provide it to people as a kick-start to their database....? Then they only need grab updated files every day or something.

<comment><AUTHOR> I think @Stephen304 is working on a way to pull seed/leech data from the DHT.

The main problem with pulling the rest of the data is that you land up with 150+ GBs of metadata rather easily

</comment></comment></comment></comment></comment></comment><comment><USER12> This is fantastic work and I can't wait to get this running on my home server. Thank you!

<comment><USER3> You're welcome! Let me know what you think, and if you have any ideas for improving it, feel free to email me or open an issue on github!

</comment></comment><comment><USER13> Cool idea. Any screenshots or a demo instance of the web interface?

<comment><USER3> I've added a couple screenshots under the features section of the website to show what it basically looks like. (I've been trying to add screenshots all day but I've been in and out of class)</comment></comment>


The Super Tiny Interpreter - <AUTHOR> https://github.com/NicholasAntonov/super-tiny-interpreter <comment><USER2> Err.... there's nothing there? Calling 'eval' is just using the existing machinery already in place, it's not really an interpreter.

Tcl is a pretty easy language to create an interpreter for:

* Jim: [http://jim.tcl.tk/index.html/doc/www/www/index.html](http://jim.tcl.tk/index.html/doc/www/www/index.html) \- originally written by antirez, now maintained by others.

* Hecl: something I wrote in Java, for mobile phones. Not much maintained any more. [https://github.com/davidw/hecl/tree/master](https://github.com/davidw/hecl/tree/master)

<comment><AUTHOR> Its probably a parody of [https://github.com/thejameskyle/the-super-tiny- compiler](https://github.com/thejameskyle/the-super-tiny-compiler)

</comment></comment><comment><USER3> It's weird that it lies about the number of lines. It says 200 when the actual count is about a dozen.

</comment><comment><USER4> Hahahahah this is amazing</comment>


Git's New Smart HTTP functionality - <AUTHOR> http://progit.org/2010/03/04/smart-http.html

<comment><USER2> Mercurial welcomes git to the HTTP party. ;-)

<comment><USER3> I always thought that Mercurial was designed for simplicity and minimalism, while Git was desinged for feature completeness.

However, given the very late adoption of HTTP, and the extremely unsatisfactory implementation of "git pull", I wonder whether this is true anymore.

<comment><USER4> The most honest technical assessment of the two I've seen yet came from the GoogleCode team when choosing which system to support: <http://code.google.com/p/support/wiki/DVCSAnalysis>

<comment><AUTHOR> that is a pretty seriously flawed report, and was even when it was released almost two years ago. even at the time, nearly everything in both the "Git Advantages" and "Mercurial Advantages" sections are either plain wrong or misunderstood. either ignore the report entirely, or read the comments with point out most of the issues.

<comment><USER5> Is it? I saw a couple of comments that rightfully pointed out some minor things the analysis ignored like git's reflog and denyNonFastforwards, but it seems reasonable to me beyond that. What other issues are there with the report?

</comment></comment></comment></comment></comment><comment><USER6> Hopefully this means git will be coming to google code! (one of the big reasons they rejected it in favor of hg was that git was so inefficient over http before)

<comment><USER7> It's not entirely unlikely, there is an issue open that has been reviewed and not rejected:

<http://code.google.com/p/support/issues/detail?id=2454>

On a similar issue requesting darcs support (which was closed WontFix), a google engineer wrote:

>Supporting Subversion and Mercurial is a lot of effort for our small team. >Adding another version control system is a lot of work and darcs would not be >our first choice.

I read that as meaning Git would be next in line, but they are not in any hurry to add it. Personally, I'd rather they concentrated on really making what they do support shine. You can always host the source on git(hub|orious) and add a Sources wiki page that points there.

</comment></comment><comment><USER8> Awesome stuff. I love how Git just keeps getting better.

Funny (to me) aside:

 _"Grack [the Rack-based Git Smart HTTP process] is about half as fast as the Apache version for simple ref-listing stuff, but we're talking 10ths of a second."_

When optimizing my web app, reducing request time by 100s of milliseconds (er, I mean, "10ths of a second") would be a monumental occasion. I dance around the room when that happens. Am I wrong in thinking "10ths of a second" might be a dramatic difference for a place like GitHub?

<comment><AUTHOR> you have to remember that this is not serving web pages - this is fetching and pushing data, which generally takes several seconds or even minutes. Having a clone take 45 seconds isn't really a big deal, but nobody would wait for a webpage load that long - it's a very different beast.

The overhead of a few hundred milliseconds is unnoticeable in almost all cases.

<comment><USER8> Ahh. I see. Thanks for that explanation.

</comment></comment></comment><comment><USER9> Could content-range be used to get similar functionality for downloading without the server-side cgi?

<comment><AUTHOR> That's interesting - I believe it is used to continue partial downloads in dumb http mode. Technically, you can figure out the bytes needed out of the packfile from the index that is downloaded, so I suppose it is possible. However, it would still be way slower than smart-http, because you would have to walk the refs one by one on the client side - one GET, figure out the next object, another GET, etc. With smart-http, you do a short back and forth until the server can figure out the entire list of objects you need and then build a custom packfile for you.

And it still wouldn't help push in any way.

</comment></comment><comment><USER10> This is awesome. Hopefully this also makes Git easier to use on shared hosting, where setting up public git daemon or giving out ssh accounts would be out of question.</comment>


Making a Brain Map That We Can Use - <AUTHOR> http://www.npr.org/blogs/13.7/2015/01/16/377631652/making-a-brain-map-that-we-can-use <comment><USER2> I'm not sure what this article is getting at. Understanding the connections among neurons is not at all like examining the atoms of a smart phone. Connectome researchers like Seung are more interested in the connections between various systems that have evolved in the brain—systems that we actually understand very well from a behavioral standpoint. We know how a lot of the brain works in precise detail up to a point, especially the vision system.

Understanding the biology of how neurons work is also critically important because that's how we'll discover new medicines and technologies that interface with the brain. If we didn't have a complete understanding of how the retina or cochlea work to convert physical signals into neural signals, we wouldn't have been able to create implants to replace these functions.

</comment><comment><USER3> > The point is not just that it is hard to understand the brain's holistic > operation in terms of what cells are doing but, instead, that it might be > impossible [...]

You can't seriously expect to develop a model of the brain while ignoring neurons and their connections. Neurons are not like atoms for a smartphone, they are like computers for the internet.

Even high level functionality like memory seems linked to dendritic spines (small protrusions of the membrane that change shape, appear and disappear in a matter of hours). Looking at the big picture is all fine and dandy, but until we have a decent model of the brain's functionality we are not in any position to decide what's superfluous and what's not.</comment>