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Tuesday, March 15, 2016

What did the Wow! Signal actually contain?

What did the Wow! Signal actually contain?


What did the Wow! Signal actually contain?

Posted: 15 Mar 2016 01:45 AM PDT

I'm having trouble understanding this, and what I've read hasn't been very enlightening. If we actually intercepted some sort of signal, what was that signal? Was it a message? How can we call something a signal without having idea of what the signal was?

Secondly, what are the actual opinions of the Wow! Signal? Popular culture aside, is the signal actually considered to be nonhuman, or is it regarded by the scientific community to most likely be man made? Thanks!

submitted by /u/CBNormandy
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Do potatoes used as batteries for clocks end up losing calories?

Posted: 14 Mar 2016 10:14 PM PDT

A calorie is a form of energy, right? So would a potato (or orange/lemon/anything) have a "caloric outtake" from being used as a battery?

submitted by /u/numb3red
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Are we travelling faster than the speed of light relative to matter outside of our observable universe?

Posted: 15 Mar 2016 05:25 AM PDT

I've been wondering this for a while now. The very reason we cannot see beyond the horizon of the observable universe is the rate of expansion, correct? So are we not traveling faster than the speed of light relative to everything beyond that horizon? And the question that follows is, of course, are we traveling backwards in time relative to what's beyond the observable universe?

submitted by /u/WMD_Right_Chair
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If gravitational paths such as orbits are conic sections, what is the cone?

Posted: 14 Mar 2016 10:05 PM PDT

I'm curious as to why a gravitationally determined trajectory, or any trajectory influenced by an inverse square law force, follows conic sections. How can I understand this?

Bouncing off of that question, is there any known relation between Dandelin spheres and Kepler's first law?

submitted by /u/ktool
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Why doesn't gasoline engines run off an auto-combustion cycle like diesel engines?

Posted: 14 Mar 2016 11:55 PM PDT

Can a mathematician explain this counter-intuitive coin toss fact?

Posted: 15 Mar 2016 05:42 AM PDT

Was reading an interesting article yesterday (https://www.quantamagazine.org/20160313-mathematicians-discover-prime-conspiracy/) and this fact it mentioned intrigued me:

"Soundararajan was drawn to study consecutive primes after hearing a lecture at Stanford by the mathematician Tadashi Tokieda, of the University of Cambridge, in which he mentioned a counterintuitive property of coin-tossing: If Alice tosses a coin until she sees a head followed by a tail, and Bob tosses a coin until he sees two heads in a row, then on average, Alice will require four tosses while Bob will require six tosses (try this at home!), even though head-tail and head-head have an equal chance of appearing after two coin tosses. "

why is this?

submitted by /u/TakeOxygen
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Why do accretion disks around black holes form vertical jets/quasars?

Posted: 14 Mar 2016 10:39 PM PDT

What's the mechanism at play here?

submitted by /u/qwoz
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Is there any research to suggest that babies look to their parents to see how to react?

Posted: 14 Mar 2016 10:14 PM PDT

For example, is there any proof to suggest that if a baby falls and the parents react as if they're horrified the baby does the same and associates falling as bad thing, but if the parents just laugh and smile the baby just giggles and moves on?

submitted by /u/SentrantPC
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What do blind people who are under the influence of hallucinogenic (and/or psychedelic) drugs, see?

Posted: 14 Mar 2016 04:04 PM PDT

Examples: LSD, LSA, 2-CB, 2-CE, Psilocybin, Salvia Divinorum, DMT ...

submitted by /u/erdnussesser
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Can someone please explain counter-steering?

Posted: 14 Mar 2016 11:28 PM PDT

As per this video from /r/motorcycles

Thank you.

submitted by /u/s-b
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How many elementary particle fields are there?

Posted: 14 Mar 2016 06:00 PM PDT

Im having trouble telling what makes two particals with similar properties the same thing and what makes them distinct. Are electrons and positrons part of the same field or different? What about left-handed and right-handed electrons? Blue and Red Up quarks? W and Z bosons? Electric and magnetic photons?

submitted by /u/chunkylubber54
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Once light is produced does it ever stop?

Posted: 14 Mar 2016 08:29 PM PDT

I just had a conversation with my Grandfather concerning the light that comes from distant suns and how we can still see that light even if the star is no longer there. So now we're curious if light ever stops moving forward once it's been produced.

submitted by /u/Drunkjesus0706
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Can you measure the spin of a neutrino in a direction other than it's direction of motion?

Posted: 15 Mar 2016 05:26 AM PDT

If the answer is yes, wouldn't this colapse the spin function to either up or down in that direction, meaning that the spin, in the basis of the direction of motion, is a little up and a little down (half and half if the direction is perpendicular)? That is, wouldn't measuring the spin of a neutrino in a direction other than it's direction of motion collapse its state to a little uleft and a little uright? But since neutrinos are always left... If the answer is no, why can't we?

submitted by /u/gastonmaffei
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If the ice caps melted and the seas rose, would it have any impact on the orbit of the moon?

Posted: 14 Mar 2016 10:47 PM PDT

I know a bit about the tidal locking that keeps the rotation and revolution synced up, still trying to grasp that relationship but it made me wonder what would happen if the variables changed. Would more ocean affect the orbit? Would it shift slightly and lock again? Could we see the dark side?

submitted by /u/DunceMSTRFLX
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Does Jupiter make noise?

Posted: 14 Mar 2016 04:30 PM PDT

If you could somehow get close enough to Jupiter to hear it, would there be anything to hear? Mostly because of the storms?

And I mean noise more than just the winds of it passing through space (if that exists )

submitted by /u/Skyphe
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What (if anything) helps prevent parents from becoming sexually attracted to their sons/daughters once they become adults? (The Westermarck effect doesn't apply to them)

Posted: 14 Mar 2016 11:08 AM PDT

What (if anything) helps prevent parents from becoming sexually attracted to their children once they become adults?

The Westermarck effect inhibits sexual attraction towards those who a person lived with during childhood. This helps prevent people from becoming sexually attracted to their siblings, parents, and others who they live with (or spend a lot of time with) since childhood. But parents are adults (or at least teens) when their children are born, so this doesn't apply.

There was an experiment where women smelled t-shirts worn by various men and rated how attractive their scent was. How attractive they found the man's scent went up with genetic difference between them, and went down with genetic similarity. (http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html)

Scent aversion is the only thing I know of which would contribute to preventing sexual attraction of parents towards their adult sons and daughters.

Is there any other research that you're aware of which shows that there are (or may be) other things inhibiting this?

Also, does anybody know if this t-shirt experiment was repeated with men being the ones smelling shirts worn by women?

submitted by /u/ogdlibt
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Why is Jupiter considered a gas giant if it's mostly made out of liquid hydrogen?

Posted: 14 Mar 2016 04:52 PM PDT

I was told that Jupiter was a gas giant, and that it was mostly made out of gas. But I got really confused when I considered the pressure inside it was huge because of the dense atmosphere above it, then I read that below 50 km the atmosphere was considered liquid hydrogen, and below that, metallic liquid hydrogen. So why is it called a gas giant if it's made out of liquid? I'm considering that it's because the hydrogen is a gas under ambient conditions here on Earth, but I'm not satisfied with that and I know the answer is probably complicated. So, is it gaseous, or liquid?

submitted by /u/Breno_Targa
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Is it true that all ocean dwelling mammals have a terrestrial ancestor?

Posted: 14 Mar 2016 03:16 PM PDT

I'm not necessarily asking if they all share the same ancestor, just that they all share some terrestrial ancestor.

My friend says that the evolutionary path of all ocean dwelling mammals shows that their ancestors came from the water, evolved more and left the water, and then evolved still more and went back to the water. Is this accurate?

submitted by /u/abcdseven
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Why is it, cognitively speaking, so hard to explain or comprehend a new card or boardgame without just playing it?

Posted: 14 Mar 2016 05:29 PM PDT

Is there any evidence for prehistoric animals whose intelligence approached or exceeded that seen in modern whales?

Posted: 14 Mar 2016 01:48 PM PDT

If quarks always exist in pairs, why are there 3 quarks in protons and neutrons? Is one unpaired?

Posted: 14 Mar 2016 04:58 PM PDT

I've heard that quarks are always paired together; so much so that the energy required to separate them would transform (based on the mass-energy equivalence) into two more quarks that would subsequently pair with the original two. Wouldn't that mean that one of the quarks in a proton or neutron is unpaired?

submitted by /u/Carl_Sagan21
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Does your body metabolize food quicker the more hungry you are?

Posted: 14 Mar 2016 07:42 AM PDT

In the linked SciAm article, researchers found a weird pattern in the last digit of prime numbers. But what does that actually mean beyond base 10?

Posted: 14 Mar 2016 12:08 PM PDT

The article: http://www.scientificamerican.com/article/peculiar-pattern-found-in-random-prime-numbers/?WT.mc_id=SA_DD_20160314

Summary from article: Prime numbers near to each other tend to avoid repeating their last digits, the mathematicians say: that is, a prime that ends in 1 is less likely to be followed by another ending in 1 than one might expect from a random sequence. But if the sequence were truly random, then a prime with 1 as its last digit should be followed by another prime ending in 1 one-quarter of the time. That's because after the number 5, there are only four possibilities—1, 3, 7 and 9—for prime last digits. And these are, on average, equally represented among all primes, according to a theorem proved around the end of the nineteenth century, one of the results that underpin much of our understanding of the distribution of prime numbers. (Another is the prime number theorem, which quantifies how much rarer the primes become as numbers get larger.) Instead, Lemke Oliver and Soundararajan saw that in the first billion primes, a 1 is followed by a 1 about 18% of the time, by a 3 or a 7 each 30% of the time, and by a 9 22% of the time. They found similar results when they started with primes that ended in 3, 7 or 9: variation, but with repeated last digits the least common. The bias persists but slowly decreases as numbers get larger.

So, okay, interesting result. But what occurs to me is that we're looking at the last digit from the standpoint of base 10 numbers (or modulo 10), which is hardly a mathematically natural thing. What does this really mean in the general case when you remove the human base-10 bias?

submitted by /u/nairebis
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Monday, March 14, 2016

Happy Pi Day everyone!

Happy Pi Day everyone!


Happy Pi Day everyone!

Posted: 14 Mar 2016 05:59 AM PDT

Today is 3/14/16, a bit of a rounded-up Pi Day! Grab a slice of your favorite Pi Day dessert and come celebrate with us.

Our experts are here to answer your questions all about pi. Last year, we had an awesome pi day thread. Check out the comments below for more and to ask follow-up questions!

From all of us at /r/AskScience, have a very happy Pi Day!

submitted by /u/AskScienceModerator
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If got one atom to absolute zero, and I touched it, would it kill me? If not, how much matter at absolute zero would I need to touch?

Posted: 13 Mar 2016 11:30 AM PDT

A fair coin flip conveys 1 bit of information. Is there a simple physical system that conveys 1 nat of information?

Posted: 13 Mar 2016 08:53 AM PDT

A nat is the basic unit of information when natural logarithms are used. A bit is the base when using log base 2.


Edit: Thanks all for your input so far. /u/brightpixels pointed out the close correspondence between this problem and a sequence of bernoulli trials, and gave a construction capable of producing exactly 1 nat of surprise in the limit of an infinite number of random trials. /u/gibbigg provided a similar construction. /u/AugustusFink-nottle suggested observing a Poisson process over a specified interval. These solutions have exactly the right flavor, i.e., relatively simple physical processes or systems that don't require building 1/e into the solution as an arbitrary numerical constant. Neither are as simple as flipping a single fair coin, but I'm willing to accept that may be a fundamental limitation since the nat is built on a transcendental constant (as pointed out by /u/7335799168).

Several others insist that an appropriately biased coin satisfies the requirements. I agree in principle, but nobody has been able to give a simple physical construction for arriving at this. As an analogy, there are many physical constructions for the numerical value of pi. However, taking a stick and gradually sanding it down until its length is 3.14159... does not qualify as a solution. I'm not really interested in arguing the point any more than I have, so if you don't see why this isn't an adequate solution I apologize for not making it clearer.

submitted by /u/PhDinBaloney
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If water is shaken violently enough and for a long period of time, will its molecular structure begin to break down?

Posted: 13 Mar 2016 08:10 AM PDT

I am not sciencey in the least, so I have no idea if that's even a stupid question. I apologize if it is. I was just wondering if that would be possible? And if it does, would it separate into hydrogen and oxygen?

Is this nonsense?

submitted by /u/ForgotTheAlamo
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Does the brain increase in temperature when thinking more?

Posted: 13 Mar 2016 07:52 PM PDT

I understand that the brain cools itself down through the ears and head, but what if it didn't have this cooling system? Would the temperature change at all or does all the energy of thinking just go into thinking itself?

submitted by /u/Abra_Kebabra
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Does the existence of the Casimir effect prove that an Alcubierre Drive is possible?

Posted: 14 Mar 2016 01:09 AM PDT

When an atom's nucleus changes (e.g. due to radioactive decay) what happens to its electrons?

Posted: 14 Mar 2016 05:32 AM PDT

Consider an atom of 3H, for example. Its nucleus contains a single proton & two neutrons, and is orbited by a single electron.

When the atom undergoes beta decay, it becomes 3He. The nucleus now contains two protons and one neutron. Is it still orbited by a single electron (making it a positive ion), or does it obtain a second orbiting electron from somewhere?

Does the same thing happen when the nucleus changes for a different reason, e.g. nuclear fission or fusion? Does it depend on the state of matter (e.g. solid fission fuel vs a fusion plasma)?

submitted by /u/bakery2k
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Hows a perfect emitter a perfect absorber as well ?

Posted: 13 Mar 2016 10:24 AM PDT

Me and my friend are having a nice argument whether all perfect emitters are perfect absorbers as well but i say only black bodies have this property but he says all of them have this property but he cant explain why

PS english aint my main language

submitted by /u/Swapnil_Sood
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Intuition behind naming of EM vector quantities. Difference between flux density and field intensity?

Posted: 13 Mar 2016 03:54 PM PDT

I've been learning EM from Cheng (2e) and I'm having trouble understanding the intuition behind the naming of the E, D, B and H fields:

E - electric field intensity
D - electric flux density
B - magnetic flux density
H - magnetic field intensity

Why are E and H field intensities and D and B flux densities?

I've seen explanations that go along the lines of E and H being differential 1-forms while D and B are differential 2-forms. I don't completely understand the reasoning behind this. What makes E a differential 1-form? Don't calculations involving calculating E-flux inherently treat E as a differential 2-form?

In addition, I've always seen D and H as being more closely related (both related to free charge/currents etc). Why is it the case that D's analog is B (and not H)?

submitted by /u/ReallyGreatPoet
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If canned food can still be edible 2 or 3 years after canning, then why not 20 or 30 years or longer? How do manufacturers set expiration dates for long-life goods?

Posted: 14 Mar 2016 12:09 AM PDT

So I have a canned drink in front of me that was produced in 2015 and the expiration date is the same month/day in 2017. I know that milk and other foods go off after a certain amount of time and I think that's got to do with the growth of micro-organisms and stuff. It seems like once you get past the first year or so, you should kind of be "out of the woods" with regard to micro-organisms and stuff messing up your food. So how do manufacturers set the expiration date of food and drink that "expires" years after production? Is there a reason why it's 2-3 years and not 20-30 years or indefinite?

submitted by /u/FermiAnyon
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Is there a way to measure how much UV radiation it takes to cause a photochromatic chemical to change color?

Posted: 13 Mar 2016 06:04 PM PDT

Do buildings, such as stadiums, have to be designed to account for vibrations from fans and music?

Posted: 13 Mar 2016 11:02 AM PDT

I was at a lacrosse game last night that had about 12k people cheering and loud music blaring all the time. The cheap nose bleed seats i had were partly obstructed by very large I-beams so I started thinking about the buildings design, specifically how vibrations are taken into account . Do the vibrations due to music and what not have to be accounted for when designing the building?

submitted by /u/Hatandboots
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Could a pipe made from any rock or clay be harmful to smoke?

Posted: 14 Mar 2016 01:34 AM PDT

Ok, it's an odd question, I know. But the thing is, I have been thinking it would be fun to try and make tobacco smoking pipes out of carved rock or burnt clay.

However, could there be harmful traces of any metals or other compounds in some rock or clay that releases under the relatively modest heat from burning tobacco?

Edit: spelling

submitted by /u/Willowbrancher
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What are projection of vectors exactly?

Posted: 13 Mar 2016 02:28 PM PDT

What is happening on a 3d plane when I am projecting a vector on another vector? Edit:Rephrashing

submitted by /u/TheSh4d0w
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What is the probability distribution of the number of kids my wife would have to give birth to so we have at least one son and at least one daughter?

Posted: 13 Mar 2016 02:36 PM PDT

Assume we have no kids to begin with and that we keep having kids until the condition is satisfied (i.e., not all of our kids are of the same sex).

submitted by /u/SumeetGautam
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If I amplitude modulate a 10k Hz audio signal at 15 Hz, what frequency would my mind perceive?

Posted: 13 Mar 2016 12:08 PM PDT

Is it possible to construct every possible continuous curve using the standard arithmetic operations and calculus?

Posted: 13 Mar 2016 04:29 PM PDT

If i define some curve by the function f(x), and that function is continuous as well as surjective (i think i'm using that term correctly?) Can that function, in the general sense by defined using only The standard arithmetic operations, as well as derivatives and integrals. If not what is an example of a curve that cannot be?

submitted by /u/oblivion5683
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Are fears hereditary?

Posted: 13 Mar 2016 10:10 AM PDT

If neurons can't reproduce, does that mean adult humans have the same amount of neurons as newborn infants?

Posted: 13 Mar 2016 03:03 PM PDT

Do bees hibernate or migrate for the winter? And how do they keep track of seasons?

Posted: 13 Mar 2016 12:12 PM PDT

Additional question, how do I get rid of them? The showed up in my backyard over the last few days.

submitted by /u/rebelyis
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Would this matter to energy converter work in principle?

Posted: 13 Mar 2016 05:37 PM PDT

When food goes 'stale' why do soft foods (bread) turn hard while soft food (crackers/biscuits) turn soft?

Posted: 13 Mar 2016 10:40 AM PDT

Could finding the solution to the cause of hypercapnic ventilatory response (HCVR) bring us closer to solving SUIDS, COPD, and Sleep Apnea?

Posted: 13 Mar 2016 10:08 AM PDT

Currently I am writing a speech about SUIDS (Sudden Unidentified Infant Death Syndrome) and while trying to understand the syndrome I came across research which suggests the inner ear as a more likely cause of SUIDS. Then fumbling around I found articles listing the same response as a cause for the other aforementioned afflictions. Additional field :Audiology

submitted by /u/GrandLordThoth
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Sunday, March 13, 2016

Are some 3D curves (such as paraboloids, spheres, etc.) 3D "sections" of 4D "cones", the way 2D curves (parabolas, circles, etc.) are sections of 3D cones?

Are some 3D curves (such as paraboloids, spheres, etc.) 3D "sections" of 4D "cones", the way 2D curves (parabolas, circles, etc.) are sections of 3D cones?


Are some 3D curves (such as paraboloids, spheres, etc.) 3D "sections" of 4D "cones", the way 2D curves (parabolas, circles, etc.) are sections of 3D cones?

Posted: 12 Mar 2016 04:33 PM PST

How do the lasers that remove rust work?

Posted: 12 Mar 2016 09:58 AM PST

Why is Theobromine named Theobromine when it contains no Bromine?

Posted: 12 Mar 2016 09:11 AM PST

I was googling around caffeine and other xanthines and noticed the lack of bromine in this molecule, why is it named this?

submitted by /u/SplafferZ
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If we were to magnify to an almost molecular level the edge of a circle, would we reach a point when it is completely straight?

Posted: 12 Mar 2016 08:34 AM PST

Not sure if the question makes a lot of sense since English is not my first language, however what I am trying to ask is: Is there such an area on a circle which is completely straight?

submitted by /u/CultuReal
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Why are bubbles spheres and no other shapes?

Posted: 12 Mar 2016 06:57 PM PST

Up to what Richter value is linear elasticity still applicable to soil?

Posted: 12 Mar 2016 09:10 AM PST

Depending on the size of wave that passes through the earth/soil, you can model the soil's behaviour as linear elastic (at least, that's a decent assumption to make). Does anyone know up to what point this doesn't hold anymore? So when does plasticity become a part of it? Thank you for any answers! I'm interested in knowing the behaviour of soil under earthquake excitation.

submitted by /u/mojojojo1717
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Is there any essential difference between ignition by flame/spark and autoignition?

Posted: 12 Mar 2016 09:51 AM PST

I knew the difference in practical between them: for normal ignition we need "an external source of ignition, such as a flame or spark" (via Wikipedia), but this requires only a very low temperature (flash point/fire point). On the other hand, for autoignition you only need to heat/compress your fuel (and have oxygen fore sure) to a (much higher) temperature (autoignition temperature), and it will spontaneously ignite.

But my question is, what's the essential difference between them, like in microscale? Doesn't that "external source" just heat certain area of your fuel to make it "auto-ignite" like how you heat/compress all your fuel together in autoignition? What will happen if I just shoot 1400F oxygen to your gasoline?

Thanks!

(I searched previous questions. This one is similar but not the same.)

submitted by /u/fireattack
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Do people in cultures where the traditional music is in semi-tonal (non-western music) have perfect pitch to semi-tonal scales?

Posted: 12 Mar 2016 09:21 PM PST

What ranges of the EM spectrum are we currently unable to produce a light source for?

Posted: 12 Mar 2016 05:49 PM PST

Is there a conservation law associated with CPT symmetry? Shouldn't it be conservation of probability?

Posted: 12 Mar 2016 08:37 AM PST

I've been reading a lot about symmetry lately and I can't articulate why but I feel like for there to be predictable laws that comes from an ultimately statistical (random) microscopic world, that the conservation of probability must come into play. So my ultimate question is, is there a conservation law associated with CPT symmetry?

submitted by /u/_Dobis_PR
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How long would a 100km^3 block of butter power humanity?

Posted: 12 Mar 2016 02:20 PM PST

How long could a block of butter power our cars and generators, lights and factories etc. for?

submitted by /u/4Sken
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Are neurotransmitters hormones?

Posted: 13 Mar 2016 06:32 AM PDT

What if you cut the Planck length in half? Does physics break down at that point?

Posted: 12 Mar 2016 02:54 PM PST

Why can't dark matter just be neutrinos?

Posted: 12 Mar 2016 11:58 PM PST

It seems like an obvious sort of answer, so there must be a good reason it's not right

submitted by /u/chunkylubber54
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As Per Special Theory of Relativity, Length Contracts and Time Dilates. Does Length Contract in All Three Dimensions?

Posted: 13 Mar 2016 04:30 AM PDT

[Math][Physics]How can the Many-World Interpretation make meaningful statements about probability when infinity is involved?

Posted: 12 Mar 2016 02:36 PM PST

If we have a barrel containing 5 red apples and 5 green apples, then there's a 50% chance of randomly drawing a red apple from that barrel. But if we have a barrel containing 5 red apples, and infinitely many green apples, it doesn't seem like anything meaningful can be said about the probability of drawing a red apple.

I'm curious about how this relates to the Many-Worlds interpretation and Physics overall. So, say we want to describe the probability that something violates Newtonian mechanics. It seems like what Many-Worlds is saying is we just have to compute

The number of wave collapses that lead to violation of Newtonian Physics / The number of possible events produced by possible wave collapses.

But the number of possible events produced by wave collapses is either infinite or unaccountably large.

Another concrete example:

A asteroid is on path to hit earth. You want to calculate the probability that it will miraculously violate Newtonian mechanics and change course. There's a simple formula for this

The number of wave collapses that could cause the meteor to change course / The number of all wave collapses occurring between now and when the meteor hits

We can't calculate this probability because the denominator is either infinite or unaccountably large. But intuitively, we want to say that there is a probability and that it's very low. Furthermore, we would want to say that the probability starts very low and approaches zero as the asteroid approaches earth.

I'm confused about how we can make meaningful physical statements at all.

Edit, additional example:

Let's say there's a 25% chance of an event happening and a 75% chance of it not happening. We would want to say that the event does not happen in more universes than it does. But if we apply this to the Many Worlds theory, 25% of worlds is ∞ worlds. 75% percent is ∞ worlds. So how can we meaningfully say that ∞ < ∞ in this situation?

submitted by /u/EWJacobs
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X-ray Crystallography - What do the extra peaks on Patterson maps refer to/ Where are they from?

Posted: 13 Mar 2016 04:04 AM PDT

http://people.mbi.ucla.edu/sawaya/m230d/Patterson/step4a.gif The image above shows a Harker section from a Patterson map, as far as I understand the major peaks refer to the position of the heavy metal atom. But I am confused as to what the other peaks refer to. I have tried to find reference to what these peaks mean in various text books but to no avail, any help would be appreciated.

Thanks

submitted by /u/MrTakers
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How much energy is produced (converted) to useable energy in a particle collision? i.e. how to calculate available/useable energy to create new particles?

Posted: 12 Mar 2016 05:08 PM PST

I'm having trouble understanding how to exactly calculate this quantity (if its a possible/meaningful thing to do at all).

Say we have head on proton-proton collision where each has some initial momentum p (where the speeds I'm considering here are highly relativistic).

Calculating the kinetic energy of each of these is simple enough,

KE = E_total - E_rest = ( (p1*c)2 + (m*c2 )2 )1/2 - m*c2

So after calculating each of these, the total kinetic energy of the system is KE_1 + KE_2 yes?

Is this sum of kinetic energies all available to "use"? i.e. to make new particles with? On some level I know that it depends on which particles actually get created, but I'm trying to look at particle collisions in a more general way and find this quantity in a way that is agnostic of what particles are actually produced (again if its possible/meaningful).

Would a better way to look at this be to look at the total energies in the collision instead of their kinetic energies?

So

E_total = ( (p1*c)2 + (m*c2 )2 )1/2

And so the total "available" energy to work with is E_1 + E_2?

Ideally here I'm just trying to find the quantity (which is dependent on each of the particles' initial kinetic energy and mass) that represents the sum total of energy (including the rest energies of the protons, i.e. their masses are "useable" since they could conceivably be destroyed in the collision) that could be used to create new particles.

I also keep confusing myself with special relativity which I haven't mentioned here because I'm having trouble figuring out if its relevant here to be changing frames etc.

Can someone please help me to understand what I'm missing here and how this quantity might be calculated?

submitted by /u/el_arens_of_arabia
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Why do waves diffract at all?

Posted: 12 Mar 2016 09:40 AM PST

Why did nucleosynthesis in the early universe allow neutrons to merge quickly with protons, but not allow protons to merge with each other?

Posted: 12 Mar 2016 08:47 PM PST

At the time, was the pressure and temperature too low for this to happen?

submitted by /u/Dopcflood
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If I throw an object while standing on the ground, is the object's path (assuming vaccuum) truly parabolic or is it elliptical around the center of the earth like an orbit?

Posted: 12 Mar 2016 06:16 PM PST