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Monday, February 27, 2017

How can a Black Hole have rotation if the singularity is a 0-dimentional point and doesn't have an axis to rotate around?

How can a Black Hole have rotation if the singularity is a 0-dimentional point and doesn't have an axis to rotate around?

How can a Black Hole have rotation if the singularity is a 0-dimentional point and doesn't have an axis to rotate around?

Posted: 27 Feb 2017 04:53 AM PST

How could I experimentally derive the speed of light with nothing more than a convenient store trip, basic household supplies, and a car?

Posted: 26 Feb 2017 09:05 PM PST

Obviously not rock hard limits on supplies, but the general idea is basic, cheap, materials that anyone could get.

submitted by /u/TimAnEnchanter
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How deep would I have to dig into the earth to stop finding life?

Posted: 26 Feb 2017 02:05 PM PST

I assume dirt, soil, earth is home to lots of different bacteria and organisms. So how deep would I have to dig to stop finding them?

submitted by /u/Tbrahn
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Are there significant nutritional differences between kale and other leafy Brassica oleracea cultivars (collards, brussel sprouts, etc.)?

Posted: 26 Feb 2017 08:50 PM PST

Does using my gas oven in winter "waste" energy?

Posted: 26 Feb 2017 07:56 PM PST

My wife and I had a science disagreement and I'm hoping some people here can lend me their opinion.

My wife claims that using an oven frequently is inefficient and my argument is that in winter its irrelevant. Any energy you spend heating up the oven EVENTUALLY equalizes to the interior of the house which EVENTUALLY has a negative offset in the amount of time you have to run the central heating. While no one should use an oven to heat up their house for a variety of reasons (for example it doesn't circulate around the house very well) its technically very efficient.

Our oven is gas and does not vent to the outside, so my understanding is that it has roughly a 100% efficiency rating at converting natural gas to thermal energy. Our central heating is a gas furnace. I'm not sure what the efficiency rating is but it's newer which seems to be around the 90% to 98% efficiency mark.

Are there factors I'm not considering here?

submitted by /u/djslivva
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Do quantum effects affect DNA?

Posted: 26 Feb 2017 09:22 AM PST

On wikipedia, the "Quantum Realm" is defined to be on the scale of 100nm, and DNA is described to be about 2nm in width.

With these numbers, how is DNA able to maintain its structure? Shouldn't its constituent particles be able to occasionally tunnel out of the potential wells holding them in place? If so, why is this not a problem? If not, why not?

submitted by /u/prettycoolpictures
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Why is the Moon now considered a planet based on Alan Stern's findings?

Posted: 27 Feb 2017 07:12 AM PST

What exactly does his new definition change that would count the Moon as a planet? And is it possible that in the near future this new definition become the more recognized definition?

submitted by /u/KarkatTheVantas
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Calculating the volume of a pool of water on a flat surface?

Posted: 27 Feb 2017 05:15 AM PST

Hi, this real life question recently popped up for me and I'm not sure how to tackle it.

Assume there's a pool of water on a flat, non-porous surface (in this case, a tile floor). The pool of water is 16 square feet in surface area. How much water is actually in the pool? I'm not exactly sure how to calculate it because, to my mind, there's no definable depth to the pool because it's on a flat surface.

So I guess my question is, when left to its natural state, how much water does it take to spread over a 16 square feet area on a flat surface?

submitted by /u/Vogeltanz
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Why does the top quark never hadronize?

Posted: 26 Feb 2017 05:32 PM PST

If the top quark has a half-life about one-twentieth of the time required for hadronization by the strong interaction, wouldn't one in a million top quarks hadronize?

submitted by /u/Tranquilsunrise
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Does the material inside a neutron star move much relative to itself?

Posted: 27 Feb 2017 12:44 AM PST

Neutron stars will have a rotation rate around an axis, but is it understood if the material/neutronium itself will move relative to other parts of the star? Or is the material more or less static, not withstanding some other new matter coming in (like if it eats another nearby planet/star/etc.)

submitted by /u/BigRedTek
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Can we detect exoplanets that do not transit their star?

Posted: 26 Feb 2017 03:47 PM PST

It seems most of the exoplanets we discover are discovered when they transit across their star, but do we have any way of discovering planets in which the orbital plane does not transit the star?

submitted by /u/TheRealFalconFlurry
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What is the difference between the dynamical Casimir effect and hawking radiation? You are creating real particles from virtual ones in both cases, right?

Posted: 27 Feb 2017 05:37 AM PST

What factors into a flame's size (like a candle's flame). And did anyone come up with a way to calculate something like that?

Posted: 27 Feb 2017 03:32 AM PST

Why are there only 2 fissionable isotopes?

Posted: 26 Feb 2017 11:59 AM PST

Theoretically, every isotope of every element can go through fusion. Why is this not true for fission? Why is it that only Uranium-235 and plutonium-239 are fissionable?

Chemistry

submitted by /u/KryptonRogue
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How does superglue or any other strong adhesive work on a molecular level? How and why does it make the two objects stick together without any chemical process?

Posted: 26 Feb 2017 05:11 PM PST

Why are Black holes black in spite of time dilation?

Posted: 26 Feb 2017 05:50 PM PST

Anything that falls into a black hole seems to slow down to a crawl to an outside observer because of time dilation effects. So shouldn't we be able to see all the stars that have fallen into the black hole frozen in time because of this instead of just blankness?

submitted by /u/sriharivignesh
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Can we ever know if a mountain was taller than Everest in Esrth's history?

Posted: 26 Feb 2017 09:35 PM PST

Is it possible for us to figure out if we've ever had a taller mountain? Or is everest the tallest mountain ever on earth?

submitted by /u/Question_Help_Please
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Will a magnetic compass react faster the closer it gets to the magnetic north pole?

Posted: 26 Feb 2017 12:04 PM PST

My daughter and I built a water compass from a cork and needle earlier today and while we were playing around with it she asked me a question for which I was unable to find a definitive answer.

Imagine three people were standing on the surface of the Earth, one just a few feet from the magnetic north pole, one just a few feet from the magnetic south pole, and one on the equator. Each of them has an identical water compass with them (it's not freezing or windy at the poles, so just go with that) and they're holding the needles south. They release the needles at exactly the same time. Would all three compasses point north at the same rate, or would they react faster as they approached magnetic north?

My instinct is to say "yes, they would react faster" since they react to a handheld magnet much faster depending on how closely the magnet is held to the compass but I don't know if that theory scales up to planetary poles.

submitted by /u/bubonis
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How do Physicists actually come up with scientific formulas?

Posted: 26 Feb 2017 11:25 AM PST

For eg, how did Newton actually come up with the gravitational force equation- Gm1m2/r2. How did he come up with the inverse square law? How did he calculate the value of G? What precise measurements he took?

submitted by /u/aman92
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Is something that smells losing mass?

Posted: 26 Feb 2017 02:36 PM PST

Take the smell of cookies baking in the oven. The wonderful smell fills my home. Are particles in the cookies going airborne? Something must be leaving the cookies for me to smell them in another room. So are the cookies losing mass? What becomes of whatever I'm smelling? Do I have cookie dust around the house?

submitted by /u/Human_Flag
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How close could a neutron star be formed without afecting the Solar System?

Posted: 26 Feb 2017 01:14 PM PST

I'm curious about the magnitude of this phenomenon and how could it affect us. I'm also interested in knowing how much time might pass until the supernova becomes a stable neutron star.

submitted by /u/macaguamarillo
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How does oversampling affect Fast Fourier Transformation?

Posted: 26 Feb 2017 11:31 AM PST
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Sunday, February 26, 2017

Would the universe eventually return to a low entropy state after heat death due to quantum tunneling?

Would the universe eventually return to a low entropy state after heat death due to quantum tunneling?

Would the universe eventually return to a low entropy state after heat death due to quantum tunneling?

Posted: 25 Feb 2017 10:47 PM PST

If the universe reached heat death (assuming something like the big rip didn't happen first), would quantum tunneling still occur? If so, would the universe be expected to eventually randomly reach a sufficiently low energy state that stars, galaxies, and planets could reform? I assume the odds of this happening are incredibly low, but if the universe is going to sit around in heat death forever wouldn't the probability approach 1?

submitted by /u/butWhoWasBee
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Can the equations of fluid dynamics be used to describe/model the flow of electrons?

Posted: 26 Feb 2017 07:05 AM PST

Does electron capture have a bearing on the particulate nature of the electron, versus its wave description?

Posted: 25 Feb 2017 08:11 PM PST

Does electron capture have a bearing on the particulate nature of the electron, versus its wave description?

Quantum Field Theory demands that we commit to an ontology of the electron as a local ripple in the electromagnetic field, above and beyond that field's vacuum state.

Beryllium is known to decay via a process of electron capture . (see http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/radact2.html#c3 )

The Compton Wavelength of the electron has a size that is roughly on the order of the distance between the nucleus of the beryllium atom and its first inner electron orbital. This distance is between 0.90x10-10 m and 1.05 x 10-10 m . The radius of the nucleus, however is on the order of 10-15 meters.

Imagine that we have committed to an ontology of the electron as synonymous with its Schroedinger Wave. Then we dispense with having to discuss the electron's "actual location" (as if it were also a localized particle or perhaps a point particle). We may even go on to say something clever like : "the actual location has no physical meaning". In this situation, we expect that the wave-like nature of the electron denies it's ability to interact with features of the universe smaller than the deBroglie wavelength.

But from peak-to-peak of that wave, the nucleus of beryllium is approximately a factor of 0.0000159 times smaller. If electron capture physically happens (and it does happen) , and the nucleons are transformed into other particles as a result of this absorption, can we justifiably deny any meaning to the electron having a more "localized" character beyond its Schroedinger Wave and a purely QFT framework?

Your thoughts .. ?

submitted by /u/moschles
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Has SETI changed their search parameters to account for recently-announced discoveries of exoplanets in habitable zones?

Posted: 25 Feb 2017 08:43 AM PST

If SETI can now locate potentially-habitable exoplanets and calculate the round-trip time of electromagnetic emissions/broadcasts, are they focusing efforts on those locations?

submitted by /u/Avalanche2500
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On average, how far back do we need to trace an individual's family tree in order to find their most recent common ancestor with any other random person from the population?

Posted: 25 Feb 2017 07:40 AM PST

How do mirrors and the concept of left and right generalize to 4 and higher dimensional spaces?

Posted: 25 Feb 2017 10:16 AM PST

For example, does 4D space have another left/right type of symmetry that is independent of left/right? And how do mirrors work in 4D and higher spaces?

I'm reading Martin Gardner's book entitled The Ambidextrous Universe, and this thought occurred to me.

submitted by /u/MapsAreCool
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What does phase coherence mean experimentally when considering individual molecules?

Posted: 25 Feb 2017 04:19 PM PST

For example, in superfluids and quantum optics the concept of phase coherence implies that the phase of each molecule's wave function is a constant difference away from its neighbouring molecules. I also realize that phase differences can result in interference effects.

But what exact "observable" or tuneable property does phase correspond to here? Can an experimentalist (with perhaps advanced technology) independently modify the phase of a single molecule in some desired way? If so, how?

submitted by /u/CallMeDoc24
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What are some unsolved problems in Computer Science?

Posted: 25 Feb 2017 10:42 AM PST

Why is escape velocity a thing? Isn't it escape force?

Posted: 25 Feb 2017 10:42 AM PST

If I had a tiny rocket with an infinite energy supply but it could never move faster than 1 km/hr, wouldn't it eventually escape earth's atmosphere, albeit at a very slow speed?

Alternatively, if escape velocity refers to a speed where no more thrust is required to escape, doesn't that make phrases like "earth's escape velocity" really imprecise? Doesn't it depend on starting elevation and the rate of acceleration to that escape velocity?

submitted by /u/West_Wing_Did_It
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Is it possible for planets to collide in orbit?

Posted: 25 Feb 2017 08:40 AM PST

If you get metal plates or if you have prosthetics, are you unable to enter into MRI's due to magnets?

Posted: 25 Feb 2017 08:27 AM PST

Or as a broader question, if you have metal anywhere in your body due to medical issues, do you have issues being around magnets?

submitted by /u/wpphilosopher
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How does NASA detect planets near star with perpendicular disc to us as observer?

Posted: 25 Feb 2017 06:13 AM PST

Is there a physical limit to how much "space" can be put on a USB disk?

Posted: 25 Feb 2017 08:07 AM PST

Does knowing (or presuming) that a problem is solvable increase the likelihood of solving it?

Posted: 25 Feb 2017 11:54 AM PST

Regarding the story of George Dantzig solving 2 unsolved math problems because he didn't know that they were unsolved, I was wondering if there's evidence/studies showing that a presumption of solvability increases the probability of solving a problem.

submitted by /u/DrBerminverter
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Is there any/could there be any two elements that could undergo both synthesis and decomposition in the same environment?

Posted: 25 Feb 2017 03:20 PM PST

I'm asking if you could have elements X and Y you could have both

X + Y --> XY

and

XY --> X + Y

but not have to change the surroundings, and would therefore spontaneously switch between XY and X + Y

submitted by /u/fluffy465
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How did we domesticate cats?

Posted: 25 Feb 2017 03:11 AM PST

They're not pack-animals (apart from lions I guess) and most wild cats are ferocious killers (as far as I know).

So how did we manage to breed the small docile housecats?

submitted by /u/taracus
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Why are all deep trenches on Earth underwater?

Posted: 25 Feb 2017 04:12 AM PST

I know that approximately 70% of the Earth's surface is underwater therefore it would make sense for most of the deep trenches on earth to be underwater, but why aren't there any massively deep trenches/canyons/ravines on land?

While asking this question I realized that most of the deep places on earth would naturally be filled with water because it would drain in, but even the deepest lakes and seas are nowhere near as deep as a somewhat deep area of the pacific ocean, let alone a trench such as the Mariana Trench.

Why is this?

submitted by /u/TRPAlternative
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Does there exist an infinite series for all numbers?

Posted: 25 Feb 2017 12:11 PM PST

We know from basic taylor series that we can sum the reciprocals of all the factorials up to infinity and get e. We also have similar series for calculating pi and ln(2).

Excluding the case of Riemann paradox, can we generate an infinite sum for all real numbers?

And I suppose this naturally leads to another question, what about the complex numbers?

submitted by /u/Dazkins
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How are captured asteroids possible?

Posted: 25 Feb 2017 05:12 AM PST

How is it possible for a planets gravity to pull an asteroids into a stable orbit?

submitted by /u/kkingsbe
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Is a plane of single atoms visible?

Posted: 25 Feb 2017 01:51 AM PST

Let's say someone produced a sheet with infinite area that is one atom thick of some element. Could you see this sheet and if not at what thickness of atoms do you start seeing it?

submitted by /u/WHATShisNAME96
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Saturday, February 25, 2017

Are there Soviet Venera landers still intact, or even recognizable as Earth artifacts?

Are there Soviet Venera landers still intact, or even recognizable as Earth artifacts?

Are there Soviet Venera landers still intact, or even recognizable as Earth artifacts?

Posted: 25 Feb 2017 04:52 AM PST

Obviously we cannot send anyone to Venus' surface to check on their status. I was wondering if the good folks of this subreddit could put their minds together and try to extrapolate what the surface conditions of Venus have done to those landers in the decades since their respective missions. How long might it take for Venus' surface conditions to, for lack of a better term, degrade them out of existence?

submitted by /u/AveKender
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How do they put a rod into a broken femur?

Posted: 25 Feb 2017 05:53 AM PST

I know someone who broke their femur in half while skiing. I saw their x-ray and the doctors put a rod actually inside the bone to hold the two halves together while it healed. How would they do this?

submitted by /u/TougherLoki26
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How can we be sure of the precision and accuracy of modern measurement tools?

Posted: 25 Feb 2017 06:37 AM PST

Suppose I have defined a 'redditmeter' [rm] in some acceptable way (that is - I can always know that this 'thing' that I measure is indeed rm units in size). After a few months, a new way was invented to measure 0.5rm, so on so forth - we get to the smallest scales.

I logically conclude that this process is a very crude way of what happened in the way we humans measure things like length, weight etc.

But how can we be sure that the scales we measure today are actually accurate? if we can measure 0.5rm with 99% accuracy, then measuring 0.25rm might have even less accuracy, going all the way to 1*10-[integer] rm.

How can we know that our measurement tools are actually acceptably precise?

Or to put it in another words - How do we check our most modern and precise measurement tools?

Edit

Thank you for your current attempts of answering, but my question wasn't how can we be sure that a kilogram is a kilogram. To clarify furthermore - How can we be sure that the most modern measurement device actually measures with a good enough precision and not with it's measurement fault being 50% of accuracy (50% of times or 50% of given value).

submitted by /u/caluser
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What is in a vacuum?(Not the machine)

Posted: 25 Feb 2017 06:38 AM PST

Just curious what really is left when a vacuum is created. I know it's most likely going to be a quantum mechanically related answer, so please explain because I don't know much about quantum mechanics! Thanks!

submitted by /u/NotTidder
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Why are there so many different units of radiation, and how do they differ?

Posted: 24 Feb 2017 09:37 AM PST

During a recent Wikipedia tab death spiral, I was struck by how many different units we use for measuring radiation- becquerel, curie, rad, roentgen, sievert... how do they differ? Do different industries/fields use a particular unit for one reason or another?

submitted by /u/Brunoise
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How are you supposed to picture complex wave functions?

Posted: 24 Feb 2017 07:35 PM PST

intro quantum mechanics.

submitted by /u/FailAtomic
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Has geographically localized human activity in aggregate been able to impact weather patterns / other things on a small time scale?

Posted: 25 Feb 2017 12:48 AM PST

Not sure if the question is specific enough, but for example: Human population density congregates the coasts of the U.S. Is maybe the heat released from things like lighting buildings, pure body heat of that many humans, automobiles, etc -- enough to warm the air enough to maybe produce wind currents or something?

Is that many feet hitting the ground enough enough to cause some kind of impact?

(As opposed to like industrial activity or actually digging into the ground, or releasing pollutants, or global warming, etc).

submitted by /u/Reddits_For_Answers
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Why are some astronomical masers circularly polarized while others are linearly polarized?

Posted: 24 Feb 2017 07:09 PM PST

Even for particular transitions (e.g. OH 1665 MHz), there appears to be emission with both types of polarization present. Is this simply because of the stimulating photons from some external radiative pump?

submitted by /u/CallMeDoc24
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If the Planck length is 0 and the observable (or infinite) universe is 100, what value is the Earth?

Posted: 24 Feb 2017 10:31 AM PST

Just curious as to size comparison between the smallest and largest things possible.

submitted by /u/CarbonDouble
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Do all planets travel around their orbit at a fixed speed?

Posted: 24 Feb 2017 04:48 PM PST

Part 1- Do individual planets always maintain a constant speed during their orbit?

Paer 2- Do all planets in a solar system orbit their sun at the same speed? Obviously they complete an orbit at different times due to the distance but are they traveling at the same speed as each other? It seems like the gravitational pull would be weaker the father out you go, but at the same time they are moving through empty space so there doesn't seem like there would be any resistance to lessen the gravitational pull of the sun. So I guess these are physics questions.

These might be dumb questions but they've come up a few times so I figured I'd ask. Thanks for any thoughts.

submitted by /u/Zenkoopa
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[Chemistry] How do you find the Dielectric Constant of a solution?

Posted: 24 Feb 2017 04:21 PM PST

I am having a little trouble with this. I am working on finding the Debye length of solutions, but I can't find how to find the dielectric constant. I think I figured out KCl, but I am 100% stuck on CaCl2.

submitted by /u/mloos93
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If shadow can travel "faster than light", can't we use that to convey information at that rate?

Posted: 24 Feb 2017 09:29 AM PST

Okay, so my source for this assumption is actually a Vsauce video - this one (I've linked to the relevant time) - where Micheal says that if we were to cast a shadow on the Moon, and then move it, the shadow would move faster than c. This, he claims, is possible because shadows carry no information, and hence A on Earth can't communicate with B on Moon faster than light.

But why can't shadow carry information? If in front of a light source, I put a 2x2 inch grid of glass, light will go through it, and if I cover a square inch at the corner, light won't go through that bit. But now I can convey 4 on-off bits of information, so someone on the Moon could see that the shadow covers, out of the four bits on the 2x2 grid, and infer 4 binary values from them, and interpret those four values at the speed of the shadow - that is, faster than light.

What am I thinking wrong here?

submitted by /u/NSDCars5
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