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Wednesday, February 15, 2017

What is the mistake in this mathematical proof?

What is the mistake in this mathematical proof?

What is the mistake in this mathematical proof?

Posted: 15 Feb 2017 02:08 AM PST

From Hexaflexagons and Other Mathematical Diversions by Martin Gardner

a=b+c

multiply both sides by a-b

a2 -ab=ab+ac-b2 -bc

move ac to the left

a2 -ab-ac=ab-b2 -bc

factor:

a(a-b-c)=b(a-b-c)

divide both sides by a-b-c

a=b

He says that this is a fallacy, but can't you just say that c=0?

submitted by /u/Booty-Zipperooni
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In a nuclear weapon, how do the explosive lenses create a supercritical mass out of a subcritical mass, when the actual mass of the fissile material remains the same?

Posted: 14 Feb 2017 08:58 AM PST

Say you start with 3kg of plutonium in a hollow sphere shape, prior to detonation. After the explosive lenses are detonated, you (very briefly) have a solid sphere of plutonium created by the explosion. However the mass of the plutonium is still 3kg - exactly the same as the original mass. So I guess my real question is this: is the term "critical mass" a misnomer? Should it be instead, "critical density", or "critical mass per unit volume"?

submitted by /u/musicmunky
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In Quantum Mechanics, why is the de Broglie–Bohm theory (Pilot-Wave theory) not as popular as the Copenhagen interpretation?

Posted: 15 Feb 2017 06:56 AM PST

My understanding of these interpretations is pretty slim overall, so please try to ELIinHighSchool. I don't understand why the modern Pilot Wave theory isn't as accepted as the Copenhagen interpretation when it avoids paradoxes such as Schrodinger's cat. If you notice that I have some kind of misconceptions of these theories please clarify them for me. Thank you in advance!

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

Posted: 15 Feb 2017 07:05 AM PST

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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If liquid helium is the coldest substance we have commercially available to us today, how did we first cool helium down to that temperature without the use of something colder?

Posted: 14 Feb 2017 04:16 PM PST

What would the evolutionary benefits be for male mammals' testicles being located in such a vulnerable location instead of being inside the body?

Posted: 14 Feb 2017 06:33 PM PST

Being such an important organ (perhaps most important, considering an animal's ultimate goal in life is reproduction) what would/could be the reasons why mammals have not evolved in parallel to have testicles located in a much safer location inside the body rather than exposed in the way they are? I just noticed the obvious vulnerability of the organs as I am watching the AKC dog show right now, and every male dog has incredibly vulnerable jewels. Thanks!

submitted by /u/g_eazybakeoven
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Does the diffusion current have an upper limit?

Posted: 15 Feb 2017 02:40 AM PST

What happens if I completly compensate the built-in voltage of a pn-junction? There should only be a finite amout of current, due to the finite amout of electrons/holes right?

If anyone has a satisfying answer I would be much obliged.

submitted by /u/Allimania
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What's the highest frequency laser?

Posted: 14 Feb 2017 05:58 PM PST

I've been playing the game Stellaris which has a late-game technology you can research, gamma-ray lasers, which got me thinking about laser frequencies.

The wikipedia page for gamma-ray lasers certainly makes them sound like a difficult research project, not something in production. The graphic they have for commercial lasers by frequency seems to imply the highest-freq commercially available laser is pretty solidly ultraviolet. Are there higher-freq research laser, and if so, what are they used for?

Is the trouble in producing higher frequencies finding an appropriate gain medium? If so, what research is there in finding such materials? If not, what IS the main obstacle?

Further questions: if we had such a laser (gaser?) what would be some of the research, industrial, commercial, and military applications that we couldn't do with a UV laser? In particular, would this have applications in laser fusion?

Also, searching this subreddit, I found this question about doubling a lasers frequency, which doesn't sound that hard in the thread. Could this method, or some other method of raising a lasers frequency, other than the brute force approach of just accelerating the emitting device relative to the target, be used in production of a high-freq laser? How does this apply to the above?

submitted by /u/zelmerszoetrop
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I recorded some electromagnetic fields, is what I am seeing in the spectral frequency the pulses of electrical communication?

Posted: 15 Feb 2017 02:16 AM PST

http://imgur.com/a/hZEyK

I was wondering what these lines are in the spectral frequency viewer

Here is the recording - http://www60.zippyshare.com/v/tXLQQLeY/file.html

is a recording from a modem router, monitor, speaker, lights. just stuff in my room.

submitted by /u/ni-ten-ichi-ryu
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What is it called when snow forms a very light crystalline layer on the top? And how is it formed?

Posted: 14 Feb 2017 02:16 PM PST

I was in Utah and went snowshoeing when I noticed that the top layer of snow was formed of millions of small crystals. It almost looked like really short grass made of ice was covering the snow. It reflected a rainbow of colors as I looked around. I wanted to know more about this phenomenon so I could learn more about it.

submitted by /u/im_not_my_real_dad
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Does orbital localization in a molecular wavefunction imply time dependence?

Posted: 14 Feb 2017 08:58 PM PST

This may get somewhat lengthy... but I've been wondering about a few properties of localized orbitals in molecular wavefunctions. It is typically argued that any arbitrary unitary transformation can be applied to canonical orbitals, because such a transformation will leave the overall wavefunction and all observables unchanged. This is typically accompanied by the interpretation that there is no "best" way to set up the orbitals, and any set obtained from a unitary transformation is as good as any other. However, that actually raises two questions for me.

  1. Let's assume we obtained a wavefunction from a typical Hartree-Fock calculation. A localization procedure will generally form linear combinations of canonical orbitals (thus, eigenfunctions) to different energy eigenvalues of the Fock operator. But doesn't that mean that the localized orbitals are basically a superposition of eigenstates, which is not a stationary solution to the (time-independent) Fock operator anymore? Nobody talks about localized orbitals as a time-dependent concept, which makes me feel that my assumption may be wrong for some reason.

  2. Tapping into an old battlefield of MO and Valence Bond theories: Some people like to use the photoelectron spectrum of methane to highlight the correct symmetry behavior of the canonical molecular orbitals. This symmetry is obviously broken if we localize the orbitals in order to willfully represent four equivalent C-H bonds. So, my question is: How does the argument uphold that any unitary transformation leaves the orbitals just as viable, if localization can introduce such an obvious contradiction to reality? Would a time-dependent interpretation as a non-stationary superposition state be able (or perhaps, even necessary) to reconcile theory and experiment?

submitted by /u/RapidCatLauncher
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Why do the "biggest stars in the Universe" basically all appear in the Milky Way?

Posted: 14 Feb 2017 05:18 PM PST

I was looking at a list of the biggest stars in the universe and they were all relatively close to earth. It doesn't seem possible that with so many stars in the universe, most of the largest ones would be located within our own galaxy.

Can we not see stars in other galaxies?

Obviously I know these are just the biggest stars that have been observed, and that this is not a definitive list, but something doesn't make sense to me.

submitted by /u/harrybro
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How does the fusion of 4 hydrogen atoms create helium and not beryllium?

Posted: 15 Feb 2017 04:50 AM PST

At about 8min15sec in this video, we are told that 4 hydrogen atoms going through nuclear fusion creates a helium atom. Why is it not beryllium if there are 4 protons?

submitted by /u/dilirst
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At what point does the first radio signal from earth just become an indistinguishable part of the background?

Posted: 14 Feb 2017 03:27 PM PST

Given the strength of the first radio signal, how far did/will it go in space without dissipating to the point where it is indistinguishable from noise?

How have modern signals changed to differ in their longevity in terms of viable distance traveled, and why?

submitted by /u/AnArmyOfWombats
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Why does the Wu experiment prove that parity is not symmetric?

Posted: 14 Feb 2017 10:26 PM PST

I believe I understand the experiment, that the magnetic moment of Co60 atoms were lined up in the same direction, and the direction of electron emission during beta decay measured.

What I don't understand is why this proves the universe has a handedness, and not just that the weak force and magnetic moment are interrelated, or some smaller structure influences both the weak force and magnetic moment.

I mean, given a changing electric field, you can predict the direction of a magnetic field, but all that means is that they are aspects of the same process, not that some basic quantity isn't conserved.

submitted by /u/MapsAreCool
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Is it possible for Hubble to image Voyager?

Posted: 14 Feb 2017 04:00 PM PST

Why is it when you handle some foods (like onions) the smell will stay on your hands for several hours, even if you wash your hands more than a couple times?

Posted: 14 Feb 2017 02:23 PM PST

Are neutrons the only things that can actually physically touch?

Posted: 14 Feb 2017 02:03 PM PST

I know people can't actually ever touch each other, they just feel the repulsive force of electrons on a macro scale. Since neutrons have no electromagnetic attractive or repulsive force, can they actually fully come into contact?

submitted by /u/ThatTallDude326
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Do magnetic fields carry information?

Posted: 14 Feb 2017 07:08 PM PST

I know that radio waves (or any EM radiation) generates a magnetic field along with the E field, but I cant find out if the magnetic field somehow carries that same information. (for example, would the magnetic field of a radio transmission carry the same information in it as the transmission itself?)

submitted by /u/FoggyDonkey
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vào lúc No comments:

Tuesday, February 14, 2017

When they repave a road, where do they send the old asphalt and what is its environmental fate?

When they repave a road, where do they send the old asphalt and what is its environmental fate?

When they repave a road, where do they send the old asphalt and what is its environmental fate?

Posted: 14 Feb 2017 05:20 AM PST

We know that people have the ability to have a "perfect pitch" with their hearing. Is there such phenomena with other senses? If not, what is so special about hearing?

Posted: 13 Feb 2017 06:12 PM PST

Special Relativity: If an object accelerates at a constant rate, does the progressively increasing time dilation cause an asymptote for the moving objects time?

Posted: 13 Feb 2017 05:17 PM PST

So, I was looking at what would happen as an object accelerated at a constant rate - say, 300 km/s2. From what it would appear from my math, the object would experience increasing levels of time dilation (from the perspective a stationary observer).

A system of (relatively) stationary observers would watch the clock on this accelerating object, and would record slower and slower increments of time. It looks like this would create an asymptote, or a point in time that the moving object will never reach. So two questions:

1) Is my math correct here? Will this object accelerating at 300 km/s 2 approach a time that it will never actually reach in my frame?

2) If so, I'm having trouble interpreting the results. In order for the stationary frame to not be "special", the moving object needs to be able to potentially reach any time within its future... but doesn't this mean there is no corresponding X,Y,Z coordinate that this object will exist in when the clock passes the time I've calculated as the limit? Wouldn't this mean that this moving object cannot exist in my universe at that time? Either way, where the heck is it at that time?

It seems like this would create a contradiction....

submitted by /u/AgentSmith27
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How does light frequency work on medium interchange?

Posted: 14 Feb 2017 02:50 AM PST

Hi I'm a chemistry trained teacher tackling a senior physics class. I have a good general knowledge of all science and have studied physics at university. However a question has stumped me regarding light waves. The textbook question asks what would the frequency be for violet light (420nm) as it passes through window glass, refractive index given as 1.51. When calculating the answer I adjusted the speed of light through glass then used v=f*lambda formula to calculate the frequency. However the text book answer has used the speed of light as 3 x 108. After quick research I found something stating the frequency would stay the same crossing the interface but the wavelength and speed change proportionally meaning you can simply calculate the frequency using the speed of light through air/vacuum. So what is this magic? The answers I found didn't explain it well enough or too well.

submitted by /u/niamedregel
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Can you feel very strong radiation?

Posted: 14 Feb 2017 12:53 AM PST

Hello scientists

I read about a thing called the Elephants Foot, it's from the Chernobyl disaster. It is said that 300 seconds of exposure to its radiation would mean certain death after a few days shortly after the meltdown. Its radiation has weakened, but still is very dangerous, but I was wondering if you would feel the radiation if you stood next to it shortly after the meltdown, and if so what it would feel like?

submitted by /u/Twixbr0
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What does it mean if a wave function equals 1, independent of position (x)?

Posted: 14 Feb 2017 04:33 AM PST

I have been looking at wave functions on MIT's YouTube channel (I'm not studying a course, or anything) and there's one thing that seems so weird. If you take the rootnorm of a wave function eikx you get the probability which is in this case 1. I've gotten that through my own calculations and they confirm it in the MIT lecture. However, my interpretation is that, whatever position (x-value) you enter you get 1, and therefore all the positions in the universe have probability of finding the particle with 100% success rate. It doesn't matter where you look, because the probability is suddenly independent of the position, and even stranger, is always 1. But that doesn't make sense!! In the lecture they just say that there's an even probability everywhere and therefore no position has a favor, but they're not mentioning that the probability is 1 everywhere and that the particle should therefore certainly be everywhere (for real, not like the uncertainty principle).

I'm guessing it's safe to assume that the professor in the lecture is right and my amateur interpretation is incorrect, but could anyone explain how I have misunderstood this 100% probability of finding the particle everywhere?

submitted by /u/Rubic-Cube
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How did they take this picture (link in text) of the sun without the ridiculous intensity of light obscuring the image?

Posted: 13 Feb 2017 09:22 PM PST

Why do people's urine come out at different strengths?

Posted: 13 Feb 2017 07:56 PM PST

Spent too much time thinking how to phrase this question, so I just went with it.
What I mean is that when we pee, we shoot urine out of our bodies seemingly at different strengths, why is that?
Also, is there a correlation between urinating-strength and age?

submitted by /u/Beezlebug
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If UV light is invisible, why do UV LEDs (on blacklights etc.) have that unique violety-blue colour?

Posted: 14 Feb 2017 03:54 AM PST

Just wondering why you can see that unique colour if UV light is meant to be invisible. Is it actually the colour on the cutoff of the spectrum where it turns into UV?

submitted by /u/patternboy
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What is missing from the theoretical model of physics that prevents us from replicating everything as a simulation? (something along the lines of the matrix)

Posted: 13 Feb 2017 04:04 PM PST

What sort of computing power would you need for that kind of simulation?

submitted by /u/Two_Skill_invoker
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What's at the bottom of the ocean?

Posted: 14 Feb 2017 02:45 AM PST

Why does a neutron star collision gamma ray burst last only seconds?

Posted: 13 Feb 2017 12:42 PM PST

I just want to know why the collision and formation of a black hole will only produce this burst for such a tiny amount of time? Is that two seconds detectable, or does it have a two second emission time?

submitted by /u/WhatIsMyGirth
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Do species which exhibit sexual dimorphism also exhibit higher degrees of behavioral difference between sexes?

Posted: 13 Feb 2017 08:14 PM PST

What is the current state of light based computing? What are the problems holding us back?

Posted: 13 Feb 2017 10:36 AM PST

I know the idea of light based logic has been around for decades and researched for just as long, but I hear little about it. With Moore's law starting to get caught up in physics problems, it seems like the logical way forward. Has light based computing even been prototyped? Is there no currently visible way forward? Whats holding us back?

submitted by /u/ItsDijital
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What does the mexican hat have to do with higgs field?

Posted: 13 Feb 2017 08:11 PM PST

I've seen the mexican hat explaination for the higgs field but all the explanations never delve into what it represents. I think the vertical axis represents the potential of a particle? Does the horizontal plane represent the wave function of a particle at a point? Does the mexican hat explain how mass arises or is that something else?

submitted by /u/TejasEngineer
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Could someone explain the purpose of the ideal gas law (PV=nRT) to me?

Posted: 13 Feb 2017 12:09 PM PST

I don't fully understand the application of this law, I have a general idea of its variables however I am confused as to its uses, could someone explain it to me?

submitted by /u/Limekilnlake
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What is the effect of gravity on an ideal gas?

Posted: 13 Feb 2017 06:44 PM PST

I have a friend who is a high school chemistry teacher who just randomly asked me (summarized) "If you increased the gravity of gas particles of an ideal gas, why does the temperature spike and you get variable results for pressure?"

I guess her students were working with a simulation and they decided to crank the gravity up to max. I'm EXTREMELY out of practice but I told her that my best guess was most likely that introducing gravity means that you are now implying that the particles have some non negligible mass thus you would have to account for their various interactions. You would have to go to a more complex equation of state like Van Der Waals or the Redlich Kwong.

Am I on the right track? Her question has me curious on what the right answer is and I can't seem to find a direct answer through Google.

Thanks!

submitted by /u/OSUfirebird18
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Why/how do single nucleotide mutations and errors occur? Wouldn't a miss pair be energetically and electrically unstable?

Posted: 13 Feb 2017 05:04 PM PST

So why would these even happen in nature?

submitted by /u/3statechamp
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How do eyes adapt when you place tinted goggles/glasses over them?

Posted: 13 Feb 2017 04:50 PM PST

When I put on tinted goggles my vision will have a tinted color and after a while my vision goes back to normal. Is this my brain ignoring it like how our nose is ignored or is there another reason?

submitted by /u/OrangesAreVile
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Are There Ancient Temples In North America?

Posted: 13 Feb 2017 12:55 PM PST

I know there are temples and pyramids down in mexico and some places in the USA. But in the vast expanses of Canada, I expect there to be things hidden under the trees and hills. I have been finding artifacts all my life, but I have always felt like there must be more. Does anyone have any interesting information regarding this?

submitted by /u/Mr--Night
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Does cold work cause tin pest?

Posted: 13 Feb 2017 08:04 PM PST

I am rolling a cast tin bar and it gets brittle and gets darker. I was wondering if the cold work causes tin pest? Where can I find a Pressure-Temperature graph of alpha tin vs beta tin?

submitted by /u/smmmsadeghi
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vào lúc No comments:

Monday, February 13, 2017

What exactly would the landscape of the British Isles have looked like prior to human cultivation?

What exactly would the landscape of the British Isles have looked like prior to human cultivation?

What exactly would the landscape of the British Isles have looked like prior to human cultivation?

Posted: 13 Feb 2017 02:50 AM PST

When you look at the landscape of the United Kingdom today, the vast majority of it consists of either towns or farmland. The human race has left an enormous impression on what Britain looks like, perhaps more so than most other nations on Earth.

What would Britain have looked like during, say, the middle Paleolithic? Or at least before the development of agriculture. I've always imagined it to be heavily forested, perhaps resembling rural Canada or Scandinavia today. But I have no real knowledge on this subject - is my view in any way accurate? Or is there even any way of knowing for sure?

submitted by /u/Hooray_4_ice_cream
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Can we do anything interesting with the weak force?

Posted: 12 Feb 2017 07:00 PM PST

We are pretty good at harnessing electromagnetism to do useful things. Can we make the weak force do anything interesting or useful? I don't mean wait around to see randomly occurring beta decays, I mean set up a weak field to harness the force in some way.

submitted by /u/Beeblebrox69
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In what way does the regulation of cell differentiation in a Hydatidiform mole differ from normal tissue and embryo growth?

Posted: 12 Feb 2017 09:16 AM PST

Somehow, the order of switching on and off pathways of cellular differentiation is all screwed up and chaotic, yet enough order remains that distinctive patches of coherently organized tissue occurs? What is going on, and what is directing the hox genes this way, if they are involved?

submitted by /u/Gargatua13013
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How long would it take to fall from geosynchronous orbit?

Posted: 12 Feb 2017 05:30 PM PST

I'm assuming the object is correct distance from the earth to be in geosynchronous orbit but it's angular velocity is zero.

submitted by /u/SwimmingBare
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How does the space shuttle escape hatch work?

Posted: 13 Feb 2017 05:25 AM PST

I saw "Space Cowboys" last night, and near the end of the movie the space shuttle descends through the atmosphere, heatshields glowing. When it reaches a lower altitude they open the escape hatch, and some astronauts parachute out while the protagonists land the shuttle in "space cowboy" fashion. Yes, it's a movie, but some questions nonetheless:

Has this kind of escape hatch ever been used in real shuttle operations?

What is the effect of an open escape hatch on the ability to land the shuttle?

How realistic is the landing maneuver in the film?

submitted by /u/Greebo24
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How are we utilizing quantum mechanics in the pursuit of technology?

Posted: 12 Feb 2017 12:33 PM PST

I think my question is more basic than it sounds. I understand HOW we use it, entanglement, superposition, etc. What I'm wondering is how we even get there! Atoms themselves are so incredibly small; how do we go about manipulating electrons and fundamental particles? What kind of equipment or technology is necessary?

submitted by /u/Sam61400
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What caused the long brown stripes on the surface of Europa?

Posted: 12 Feb 2017 10:26 PM PST

Nasa released this photo of Europa and I noticed the long brown stripes on its surface. If the planets surface is ice with a large ocean beneath its surface what would cause the long brown streaks on the surface ice? Could it be meteors? This does not seem likely to me but who knows. Just thought id ask. (Source: http://photojournal.jpl.nasa.gov/jpeg/PIA19048.jpg)

submitted by /u/HTID_R3d_Panda
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What causes black holes to have an upper limit to their rotational speed?

Posted: 12 Feb 2017 07:10 PM PST

Wikipedia mentions the theoretical upper limit to how fast a black hole can rotate. What is the limiting factor?

submitted by /u/Uveerrf
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How would a negatively-charged gas mixture react when propelled when enveloped in an extremely positive gas "shell"?

Posted: 12 Feb 2017 05:26 PM PST

I am wondering if a negatively charged gas enveloped in a positive gas "shell" would remain intact, and how it would react. Thank you.

submitted by /u/TC01017
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If an atomic nucleus were the size of a beach ball, what observable properties would it have?

Posted: 12 Feb 2017 03:02 PM PST

For example, what would it look like, feel like, how heavy would it be, etc.

submitted by /u/Cryptoaster618
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If Venus has no EM field how does it retain its atmosphere?

Posted: 12 Feb 2017 02:22 PM PST

Why doesn't glue dry in the bottle even after long periods of time?

Posted: 12 Feb 2017 08:48 PM PST

Is it possible that instead of dark matter being a force that holds galaxies together, there's something else like space having an outward pressure?

Posted: 12 Feb 2017 11:06 PM PST

Using a 300MHz oscillator, could I make a miniature microwave transmitter?

Posted: 12 Feb 2017 07:00 PM PST

I was thinking something like this: https://cdn.instructables.com/F5M/V9NW/OT2EXCFDNO4/F5MV9NWOT2EXCFDNO4.MEDIUM.jpg

I wasn't sure if I would need to add another power source or a resistor.

submitted by /u/joosh_lux
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Is there something wrong with Bell's inequality?

Posted: 12 Feb 2017 02:51 PM PST

Something has been bothering me for a few days after watching Veritasium's video on quantum entanglement again, specifically the expected frequency for local hidden information. Can't disagree with the math, but it felt like the premise was wrong for same axis, opposite directions. Accepting the numbers given (if it's supposed to be up in vertical, then it would have preference for a certain alignment at 60°, 3/4 of the time), I drew the expected measurements for a static axis (ignore that most of these aren't actually 60°, apparently it's too hard to split half a circle in 3): http://imgur.com/a/io6wM .

Darkened area is where the north of the axis could be located given the first observation. The bottom of the page shows possible positions for the axis when knowing the answer for all 3 directions (it could never be up for vertical, then down for both 60° and -60° for the same particle, since it would need 2 axis, which doesn't make sense for 3d volumes) and what would be determinable by observating 2 particles. When we know a spin to be x in the vertical, we also know it to be 3/4 x at 60°, and 60° happens 2/3 of the time. Isn't this the same from 07:27 in the video?

So, considering the observations, it seems I reached the same expectation, which would result in the same 50% up or down on average for both inclined detectors when compared to the vertical one. Is there something too crazy here I'm not seeing?

EDIT: If I'm right about this, I might have found a mistake in my page. How can it be that the first split will also make it more likely that the axis would be towards the middle? What happens if 60° is measured first? With non locality it's easy: it just is. But preserving locality and ignoring loopholes, maybe this is only true for the vertical direction. If that's the case, then measuring 60° first, the vertical should still be 3/4, 1/4. But, the opposite 60° should be 5/8, 3/8 since it keeps the whole more likely slice (2/4, or 1/2) and half of one of the more unlikely (1/2 + 1/8 = 5/8) for the same direction.

submitted by /u/skafast
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If the Big Crunch is supposed to happen at some point, then why is the universe expanding at an accelerating rate? Shouldn't it be slowing down and/or reversing?

Posted: 12 Feb 2017 04:00 PM PST

I was reading my Physics textbook (grade 11 level) and it says "if enough mass exists in the universe, gravity could ultimately stop and reverse the expansion of our universe, leading to what is sometimes referred to as the Big Crunch."

Doesn't the singularity before the Big Bang contain all matter that exists now? If there is enough mass, why did the Big Bang happen in the first place, and all the mass not stay in its singularity form? Otherwise, would the Big Bang and Big Crunch happen over and over again?

Sorry if there's a lot of questions.

submitted by /u/Master_Cthulhu
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How was Millikan able to calculate the charge of an electron so precisely?

Posted: 12 Feb 2017 10:42 AM PST

I can't wrap my head around how he was able to calculate a value for charge in the neighborhood of 10-19 using such a crude measurement system. Anything could have impacted the measurements, from his own fatigue in eyeballing the oil drop motion and size, to slight variations in the content of the air in the system, to the vibrations of the apparatus, to his electrical measurements being imprecise due to effects like resistive heating or voltage fluctuations.

I suppose all these could be made to be less impactful by measuring more drops, OR by the charge amount on each drop being a relatively small integer, but I'm having trouble wrapping my head around the precision he was able to achieve with his experiment. (I realize he was off by something like 2%, that still doesn't change the fact that we're talking about quantities in the 10-19 range)

I must be looking at this the wrong way, can anyone help me?

submitted by /u/MapsAreCool
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Why do certain diseases have a latency stage between its secondary and final stage of infection?

Posted: 12 Feb 2017 08:27 PM PST

After reading articles about diseases like AIDS and Syphilis, many pointed out that there actually exists a latency period before the disease progress from its secondary stage of infection to its final stage.

What exactly happens during this latency period? Why is it that symptoms disappear during this latency period? Is it because our immune system is responding to the infection?

submitted by /u/XiaoFatty
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Why does Pascal's Triangle give the powers of 11?

Posted: 12 Feb 2017 12:32 PM PST

So the first five rows are self explanatory. 1, 11, 121, 1331, 14641 are 110, 111, 112, 113 and 114.

But then the next row is the first with double digits so it's not exactly a power of 11 anymore. It's 1 5 10 10 5 1, but then I noticed, 1 (5+1) (1+0) 0 5 1, or 161051 is indeed 115.

The next row is 1 6 15 20 15 6 1 so if you did what I did earlier and added the digits next to each other you get 1771561 which is 116. Etc. etc.

So any explanations?

submitted by /u/TheFireTrucker
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Is it possible to find a basis for the set of continuous functions?

Posted: 12 Feb 2017 01:27 PM PST

Following up on this, do infinite dimensional vector spaces necessarily have a basis?

submitted by /u/Shittymodtools
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Does Planck's Constant divided by Boltzmann's Constant have any particularly meaning?

Posted: 12 Feb 2017 01:36 PM PST

By dividing the constants you get roughly 4,8x10-11 Ks. Does it have any meaning in nature, and/or does it relate to any physical phenomena?

submitted by /u/AlbinNyden
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Does the hydrogen electron move in a Sine wave shape?

Posted: 12 Feb 2017 12:59 PM PST

When I took quantum physics in college, they covered the Schrodinger equation. It said that the electron around hydrogen acts like a wave. Does this mean it moves around the atom like Sine wave shape? The double-split experiment proved that electrons are both particles and waves.

submitted by /u/Gemini_Wolf
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How does the electric field behave as a charged particle falls into a black hole?

Posted: 12 Feb 2017 12:01 PM PST

Specifically, how does the field smoothly transition from the field of an in-falling charged particle to that of a spherically symmetric black hole?

It seems to imply that to a distant observer, the field due to a charge at the event horizon of a black hole would have to be spherically symmetric around the center of the black hole (at least, assuming a spherical black hole). How does that happen?

submitted by /u/sticklebat
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