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Friday, March 17, 2017

Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?

Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?

Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?

Posted: 17 Mar 2017 05:20 AM PDT

Why so many organic substances containing NO2 groups are explosive?

Posted: 16 Mar 2017 06:01 PM PDT

Is there a way for us to know what the population of any given species of dinosaur was during their time on earth? And if so, how?

Posted: 16 Mar 2017 04:32 PM PDT

Have there been any conjectures proven false, despite being widely believed to be true prior to the disproval?

Posted: 16 Mar 2017 11:42 AM PDT

Many famous conjectures (e.g. Goldbach's Conjecture) may not be formally proven, but are widely believed to be true due to strong heuristic and statistical evidence, and a disproval seems exceedingly unlikely.

Has there been a case where a conjecture, widely believed to be true for a long time, has actually been proven false later?

submitted by /u/GeneReddit123
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What would the creation of a black hole look like?

Posted: 17 Mar 2017 02:07 AM PDT

Can we pull a reflected image off a "nonreflective" surface?

Posted: 16 Mar 2017 12:42 PM PDT

Can we pull a reflected image off a "nonreflective" surface?

Reflectiveness is relative. A dirty mirror could be called reflective. A cracked or distorted mirror too. But how about white sheet of paper? Or a rock?

It may not be an image that our eye or mind can appreciate, but maybe we could run the reflected light through a noise filtering algorithm.

So I guess the real question is, how good are our reflected light image extraction algorithms? What's the limit on extractability?

submitted by /u/woodrail
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What does "m" in atomic mass number mean?

Posted: 16 Mar 2017 12:59 PM PDT

I sat down here reading and I don't seem to understand what "m" means in the ending of an atomic mass number. For an example the isotope 234m Protactinium. First of all what does it mean? And how would it affect decay?

submitted by /u/No-Yes-No
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Is there a theoretical maximum magnetic field strength?

Posted: 16 Mar 2017 06:12 PM PDT

I understand this may be expressed in terms of... what, volume of spacetime?

submitted by /u/askingyourmum
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Since the honeybee is an foreign species in North America, would it really be that bad for NA if all honeybees died out?

Posted: 16 Mar 2017 08:43 AM PDT

Since honeybees are technically an invasive species, would it have much impact? How did pollination work before bees in the Americas?

submitted by /u/pommefrits
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Quantized Momentum Uncertainty in the Particle-in-a-Box experiment?

Posted: 16 Mar 2017 08:56 PM PDT

Hello everyone. In regards to the particle-in-a-box experiment, we know that said particle can only exist at discrete wavelengths, and from the de Broglie theorem, discrete momenta as well. From this, you can also derive the discrete energy levels said particle can exist in, but my question is regarding the application of the uncertainty principle to this situation. Although our momenta can only be discrete, doesn't there exist uncertainty in the direction (i.e. left or right), and thus the uncertainty in the momenta is twice the discrete momentum? If this is true, then, my question is how exactly the momentum uncertainty can be discrete, since it seems it should be continuous. If this is false, then could someone please explain why it is? I feel like I'm making an incorrect assumption here, but I don't know where. Thanks!

submitted by /u/Quick_Question404
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How does 2,4-dinitrophenol span membranes?

Posted: 16 Mar 2017 04:35 PM PDT

In biochemistry, a question was raised that said 2,4-dinitrophenol distrupts the proton gradient created in mitochondria by acting as a proton transporting molecule. But how does it span a hydrophobic mitochondrial membrane if the molecule itself seems so polar?

submitted by /u/thathomelessguy
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In four (or three) fundamenal interactions, why only Electromagnetic force can be observed in the form of attract and repel force, while others are only attracting?

Posted: 16 Mar 2017 09:31 PM PDT

If we're trying to unite them in a unified field, why's there that difference?

submitted by /u/DogeoftheShibe
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Do logarithmic functions have to be base ten?

Posted: 16 Mar 2017 09:28 PM PDT

It seems like a lot of functions can be expressed logarithmically, such as that for sound. Is this just a coincidence that it goes along with our base 10 system or can it be expressed in any base?

submitted by /u/minnesotanationalist
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[Neurochemistry] How exactly does dopamine receptor downregulation cause the impulse to go get more drugs?

Posted: 16 Mar 2017 05:03 PM PDT

So I just finished listening to "The Addictive Brain" on the Great Courses and there was something I wanted to make sure I'm understanding right:

I get that with frequent use of something like cocaine, postsynaptic dopamine receptor availability decreases. However, how would this aid in the impulse to go out and seek the drug?

I understood from the course that for an addict, pleasure gained from the drug decreases with use and craving for the drug increases. And, environmental cues or triggers will convey to the addict that this is the familiar situation in which the behavior of buying drugs leads to a big reward, so dopamine rises in response to the trigger and the drug addict performs the drug purchasing behavior. However, if their dopamine receptors become more and more downregulated with drug use, wouldn't their impulse to purchase the drug be lessened because of this?

That is, the presynaptic dopamine release may get bigger due to stronger establishment of triggers (thanks to VTA), but because the postsynaptic dopamine receptor availability is decreasing, shouldn't the capacity to produce an effect (impulse) be lessened?

I'd really appreciate any clarification on this. Or, if what I've written above shows that I'm misunderstanding some mechanism please let me know

submitted by /u/batslicecameltruck
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Considering the fact, that bananas contain unstable radioactive isotopes of potassium, how many bananas would it take to give an average human radiation sickness ?

Posted: 16 Mar 2017 08:49 AM PDT

What is the Hellmann-Feynman Theorem?

Posted: 16 Mar 2017 07:34 PM PDT

Hi! I was recently suggested to read researches regarding the Hellmann-Feynman Theorem. As a result, I started with Wikipedia, as I assumed it would have the simplest version of it with clear explanations.

Nevertheless, despite reading the entry in Wikipedia, alongside a few research papers and lectures. I'm still a bit clueless regarding it.

Could anyone provide me a simple explanation of what the theorem states and how it is used in the applications mentioned in Wikipedia? Additionally, why must the eigenfunction be normalized and why must is be continuous with respect to the parameter of the Hamiltonian?

Thanks!

submitted by /u/B345tM0d3
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Does computer audio have something like a framerate?

Posted: 16 Mar 2017 10:41 AM PDT

I was using a Midi keyboard the other day and I noticed that there was a delay between pressing the keys and when the software played the notes (FL studio). When I went into the settings it said there was an intentional delay, and if I changed audio drivers it allowed me to lower it by a few milliseconds, but anything below around 30 ms delay would make the sound inaudible.

My immediate thought was how did they need delay when video games would make a noise instantly when you press a button. Is there some sort of "framerate" in computing that the audio needs to sync to?

submitted by /u/Njlamp
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Is there a critical age for someone's learning/development? [psychology]

Posted: 16 Mar 2017 09:27 AM PDT

Is there an age range where we learn the best? worst? Can't you learn at all ages?

submitted by /u/InsaneBaz
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Thursday, March 16, 2017

PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?

PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?

PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?

Posted: 15 Mar 2017 10:21 PM PDT

Also, does the size of a pulsar matter much when determining the break-apart speed?

submitted by /u/Jaracuda
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 15 Mar 2017 08:04 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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When there is an eclipse, why does the earth not become cold for that period?

Posted: 16 Mar 2017 05:08 AM PDT

Is the LHC beam visible to the naked eye?

Posted: 15 Mar 2017 08:10 AM PDT

If so, what would it look like? A bright, Science-Fictiony energy beam?

submitted by /u/PrequelMemeMaestro
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Why do even atomic-numbered elements (hydrogen neglected) seem more abundant?

Posted: 16 Mar 2017 03:43 AM PDT

In the solar system, neglecting hydrogen, 11 of the next 12 most abundant elements have an even number of protons--with nitrogen being the odd one out. And the bar graph from this page clearly shows a see-sawing pattern preferring even-proton elements as they get heavier. I've read about the Oddo-Harkins rule but it doesn't exactly explain the mechanism. Why is that?

submitted by /u/lordvadr
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What's under the desert?

Posted: 15 Mar 2017 11:14 AM PDT

If I were to get a fairly large vacuum cleaner and vacuum up all of the sand in the Sahara desert, what would I find underneath? Rock? Clay? Magma?

And how deep does the sand go anyway?

submitted by /u/PaulsRedditUsername
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Are there any big math discoveries still to be made?

Posted: 15 Mar 2017 09:35 AM PDT

Maybe I worded this wrong. But so many other sciences have big problems waiting to be solved. Physics for example is waiting for some grand unification theory. Biology has thousands of problems waiting to be solved. From cures to diseases to how did life begin.

So what about math? Have we pretty much figured it all out? Am I right to even try and compare it with other sciences in that regard?

Thanks to anyone who might take the time to answer.

submitted by /u/caper1144
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How fast can a nuclear powerplant shut down safely?

Posted: 15 Mar 2017 12:52 PM PDT

In a hypothetical scenario there is an impeding catastrophe that will affect the area of the plant. How fast can a nuclear power plant shut down so as to be safe and prevent radiation?
I am not asking to store away the nuclear waste and fuel in underground secure locations.
Just to make it safe and not worry about it for as long as possible.

submitted by /u/theofanhs
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If you walked in a straight line around a small asteroid long enough, would you eventually increase its spin enough to walk off into space?

Posted: 15 Mar 2017 01:59 PM PDT

Basically what I just asked.

submitted by /u/manufacture_reborn
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Is it possible to feel pain from strong ionizing radiation?

Posted: 15 Mar 2017 12:55 PM PDT

Not instant, but around 10 minutes after the exposure, experiencing joint/muscle aches? If there have been some instances where a subject "feels" pain after knowing he or she has been radiated, is it purely psychological?

submitted by /u/hawkiee552
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Is there a direct connection between the Uncertainty Principle and the Third Law of Thermodynamics?

Posted: 15 Mar 2017 09:09 AM PDT

I understand that Thermodynamics deals with entire systems. But in the single particle case, if it can never be cooled down to absolute zero, it will always have some vibration/motion. This seems very similar to the Quantum Physics idea that a particle only has a probability to be at a specific range [delta]x. Are these two versions of the same concept?

submitted by /u/mark0136
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What's the point of quantum teleportation, if you need to physically move an entangled particle to the desired end location? Couldn't you simply move the original particle instead?

Posted: 16 Mar 2017 04:00 AM PDT

I just watched minutephysics' video on quantum teleportation. One question I've always had it doesn't answer is: why bother? You need to physically move a bunch of matter to the location you want to teleport to, why not just move the thing you wanted there instead?

submitted by /u/MG2R
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Are the veins in a penis symmetrical?

Posted: 15 Mar 2017 04:25 PM PDT

Do rockets suffer from aerodynamic drag caused by truncated tail?

Posted: 15 Mar 2017 02:56 PM PDT

I don't know the right terminology so please let me explain.

In car and airplane aerodynamics, engineers have to consider not only aerodynamics on the front-facing side of the vehicle, but also on the back side. The idea is to reduce turbulence and low pressure, which has the effect of "pulling the vehicle back". I imagine this by having a moving object creating a vacuum (low pressure) behind itself, which "sucks in" everything around, including the object itself. Better shapes of the object will allow more air to fill out the vacuum (low pressure) area quicker, which will induce lower "pulling" force on the object.

Now the question is, what about rockets? If you look on this picture of the tail of Saturn V, it clearly shows how the rocket body is simply "cut off", or flat, and then the engine nozzles stick out. In my mind such moving body has to create lots of low-pressure-pulling force in the area between the flat rocket bottom and the tips of the nozzles, especially at high speeds.

Now obviously it cannot be perfectly aerodynamic as we may need some nozzle gimballing, or have the incoming air cool the nozzles down a bit, or simply vibrations prevent us covering up the engines/nozzles. But such a flat surface simply looks like a beginner's first attempt at rocket design (no offence :) ).

Or is that simply ignored due to short time spent in the dense part of the atmosphere?

submitted by /u/bremby
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Is proton beam radiation more effective than standard radiation for cancer treatment?

Posted: 15 Mar 2017 12:59 PM PDT

Do red shifted photons lose energy?

Posted: 15 Mar 2017 01:01 PM PDT

So say there are two hydrogen atoms in the same frame of reference in a vacuum- one in an excited state and one in ground state. The electron in the excited state drops to its ground state and releases a photon. The photon is absorbed by the electron in the other atom and it goes to an excited state.

What happens if they are not in the same frame of reference and the first hydrogen atom is moving away from the the second. Since the frequency of the photon is smaller when it reaches the second atom, is there enough energy to excite the electron? If not, where did the energy dissipate?

submitted by /u/banjoist
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[Math] How exactly is mass points used and when in a problem can you use it?

Posted: 15 Mar 2017 09:39 PM PDT

Additionally, when can you split a single point A up into points of mass A1 and A2 then later add them together? Can a point be split up into more then 2 points?

submitted by /u/AccountName77
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Does Moore's Law have a limit?

Posted: 15 Mar 2017 12:42 PM PDT

Does it predict an ever increasing doubling or is it bound to 'slow down' or even plateau at some point? Why?

submitted by /u/Velteau
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How would a compass act in space?

Posted: 14 Mar 2017 10:07 PM PDT

What would a magnet act like as you traveled away from earth? Would it continue to point towards the earth's pole or would other magnetic fields take over at some point?

submitted by /u/oceanceaser
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Wednesday, March 15, 2017

[Math] Is every digit in pi equally likely?

[Math] Is every digit in pi equally likely?

[Math] Is every digit in pi equally likely?

Posted: 14 Mar 2017 11:11 AM PDT

If you were to take pi out to 100,000,000,000 decimal places would there be ~10,000,000,000 0s, 1s, 2s, etc due to the law of large numbers or are some number systemically more common? If so is pi used in random number generating algorithms?

edit: Thank you for all your responces. There happened to be this on r/dataisbeautiful

submitted by /u/LtMelon
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How did we first estimate/calculate the size of and distance to the moon?

Posted: 14 Mar 2017 11:01 AM PDT

Conceptually speaking, what does it mean when you take a number to a power that is not a rational number?

Posted: 14 Mar 2017 09:22 PM PDT

So, my understanding of exponents is basically as follows. Say you have na/b. What this basically means is that you need to do two things to the number n - you need to multiply n by itself a-1 times, and then you need to take the bth root of that result.

So, for example:

  • 32 means 3 * 3 = 9
  • 41/2, or 40.5, means 4, and then you take the square root of 4, which is 2.
  • 53/4 , or 50.75, means 5 * 5 * 5 = 125, and then you take the 4th root of that, which is ~3.3437...

Ok, so that makes sense to me. You can then add on the idea that if either a or b is negative, you just do all of this stuff and then take the reciprocal. And so:

  • 2.5-5/2, or 2.5-2.5, means 2.5 * 2.5 * 2.5 * 2.5 * 2.5 = 97.65625, and then you take the square root of that, which is ~9.882117, and then you take the reciprocal of that, which is ~0.101192

In order to do this, both a and b must be positive integers, because its an iterative process - you can't multiply something by itself 2/3s of a time. But usually you'll be able to express a/b in the form of positive integers.

What doesn't make sense to me is that you can somehow take numbers to the power of things which are not rational (e.g. a/b can't be expressed as a ratio of positive integers) and therefore can't follow this step by step process. I guess there's two different categories here, which are:

  • Exponents which are real but irrational (either transcendental or not). So, for example, how can you take nπ or ne? In these cases, the exponent can't be expressed as a fraction, and so you can't really do the two step process of taking n, multiplying it by itself a-1 times, and then taking the bth root. We can get rough estimates, I suppose (for example, you can use 22/7 or other similar fractions for π), but is that how we actually do this? Or is there some other conceptual way to think about exponents which permit irrational exponents?

  • Exponents which are complex numbers. This is really why I started to think about this entire question, as I was doing some (very basic) learning about the Reimann Zeta function (which I posted about here yesterday and got awesome responses about). That function requires taking numbers to the power of a + bi. And I just don't even know what that means. I know I can type it into google and an answer will spit out, but it just doesn't make conceptual sense to me based on my understanding of what an exponent is.

Any insight would be awesome. Thanks!

Note: I asked this question on /r/AskMath earlier, but didn't get very much of a response and got no answer to the second half of the question. Hoping I might get a better answer here.

submitted by /u/VStarffin
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Was the Velociraptor species as intelligent and clever as the Jurassic Films portrayed them to be?

Posted: 14 Mar 2017 11:42 PM PDT

Wouldn't it be faster to break up and transmit radio signals through space across multiple channels rather than use a single channel?

Posted: 14 Mar 2017 03:53 PM PDT

For example, if you take a picture from the surface of mars and the file size is 4 GB and then you send that picture to earth at 1GB a minute then that takes 4 minutes. If you split the data up into 4 parts of 1GB each and then send those 4 parts simultaneously on 4 different channels then the picture only takes 1 minute to get to earth.

submitted by /u/Azozel
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What are the differences between waves?

Posted: 14 Mar 2017 04:28 PM PDT

I hear sound waves, I see light waves, and I would feel micro waves if they were in a high enough concentration. So what is the difference between then?

submitted by /u/Hiimsimba
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[Physics] How did Balmer arrived at his formula if there was no concept of energy levels or atomic orbitals at his time?

Posted: 15 Mar 2017 04:46 AM PDT

Black hole = magic refrigerator?

Posted: 14 Mar 2017 05:53 PM PDT

Assume I have a large black hole.

And that I have an environment that is extremely hot due to photons flying everywhere.

Let's say I build a giant machine to transfer those photons into the black hole. Not just in the immediate vicinity, but across a vast area.

My question is, is there any limit to how large a machine the hole would be able to cool off by having the material transfer heat into it via radiators or similar. Like, if I built a machine much larger than the actual event horizon that is meant to pass heat into the hole, is there any reason in particular I can't cool the entire machine to the temperature of the hole? Like can I essentially use it as an unlimited thermal wastebin that gets colder and bigger the more heat I throw in it?

submitted by /u/pds314
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Do snow covered mountains still erode?

Posted: 14 Mar 2017 07:21 PM PDT

If the temperature on the mountain never reaches below zero, I figure the only source of erosion is the wind. But when the mountain is covered with snow, does it not act as a barrier between the wind and the mountain?

submitted by /u/itsalilbitlit
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Aren't General Relativity and quantum mechanics just fundamentally, irreconcilably incompatible?

Posted: 15 Mar 2017 01:06 AM PDT

In GR, space and time are facets of a single "thing" and it seems to me that momentum pops out mechanically. There's no inherent limitation on measurement precision built into GR, just like in Newtonian physics.
 

On the other hand, with Heisenbergian inequalities all over the place, we have to choose carefully what we try to measure simultaneously. These limitations on measurement are built right "into the code" of the universe.
 

I just don't see how these theories could ever be unified when they don't even appear to speak the same language. Is there something I'm missing?? (besides, of course, an 8 years in a physics degree program at a university..)

submitted by /u/rpgZenMaster
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Why does a screen recording program not crash when it records itself?

Posted: 14 Mar 2017 07:00 PM PDT

When a screen recording software, such as OBS, records itself, it creates a tunnel effect. If OBS infinitely records itself, why doesn't that make my computer crash/slow down?

submitted by /u/Gifhero
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What does string theory does differently that current theories do not when dealing with singularities?

Posted: 14 Mar 2017 08:27 AM PDT

From what I gather, in string theory we naturally unify QFT and GR, so does it solve the problems that we encounter at a singularity? If so, what explanation does it offer when particles are broken down to their fundamental bits inside a black hole. Please shed light on how our understanding of black holes, and singularities would further if string theory is indeed true?

submitted by /u/elder--wand
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Can a neural network spit bars?

Posted: 14 Mar 2017 03:57 PM PDT

i was watching a video of a neural network learning to speak clearly and my first thought was "when this speaks english perfectly will it be able to rap?" since rap is heavy on the vocabulary it seems fitting to me

to expand on my question, can a neural network rhyme, use word play and make references like a rap song does?

submitted by /u/TubbyMcFuckles
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Why do batteries have a little "nub" on the positive end?

Posted: 14 Mar 2017 11:05 AM PDT

If light was travelling in a 2d circle, would the angular speed of light still be c?

Posted: 14 Mar 2017 07:05 PM PDT

Is it possible for a star of ridiculously high mass and the proper composition to effectively collapse into a black hole so quickly that no supernova is observed outside the event horizon?

Posted: 14 Mar 2017 01:58 PM PDT

I understand (at a very high level) the life processes of a star, balancing gravity's pressure with fusion's outward-pushing energy, until (in some cases) the star begins fusing Iron, which is not an exothermic reaction, and gravity forces the mass of the star together past the Chandrasekhar limit where electron degeneracy pressure can no longer support the growing iron core, and boom. Hopefully I've got that mostly correct within the scope of this question.

I've read that some low-metallicity stars of "only" several dozen solar masses can undergo core collapse and produce a black hole without a supernova - is that effectively what I'm describing in my question text? Or is that happening via some other process?

What about when a really massive star collapses due to photodisintegration? Would that be an example of the text in my question, or is some other process occurring to create a(n) (apparently quite massive) black hole without a supernova in those cases?

Are there any other theoretical cases where a star massive enough to produce a supernova and collapse into a black hole does not actually produce said supernova yet still collapses into a black hole? Or, worded another way (as I hopefully conveyed in the question text), the supernova occurs, but the star is so massive that the event horizon has already formed around the supernova?

Sorry for so many sub-questions, just trying to clarify what I was originally asking and describe what I think I already know.

EDIT: Changed flair to Physics from Astronomy; wasn't sure which applied better.

submitted by /u/FrontColonelShirt
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Why aren't we flung off the surface of the earth if its spinning upwards of 1,000 mph?

Posted: 14 Mar 2017 03:07 PM PDT
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