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Saturday, July 8, 2017

During the winter, humans are known to track animals via their footprints in the snow, as we do not posses the same olfactory capabilities as say a wolf. Are there any other animals which have been observed tracking animals by means of visual cues?

During the winter, humans are known to track animals via their footprints in the snow, as we do not posses the same olfactory capabilities as say a wolf. Are there any other animals which have been observed tracking animals by means of visual cues?

During the winter, humans are known to track animals via their footprints in the snow, as we do not posses the same olfactory capabilities as say a wolf. Are there any other animals which have been observed tracking animals by means of visual cues?

Posted: 07 Jul 2017 11:49 AM PDT

If I have two blankets of different materials, does the total insulation change depending on how I layer them?

Posted: 07 Jul 2017 09:07 PM PDT

for instance, I have a cotton sheet and a polyester blanket.

Would having one on top trap heat more effectively than the other way around?

submitted by /u/High_king_of_Numenor
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Were there any islands on the "back" side of earth during the time of Panthalassa and Pangaea?

Posted: 07 Jul 2017 03:56 PM PDT

The Pacific have have quite many islands in the middle of nowhere, and I assume that remote islands were not impossible during the time of Pangaea. Are there any known Hawaiis of Panthalassa back in the day? If so, is anything known about the plant and animal life there?

submitted by /u/Cavalry262
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When you grow and your birthmark stretches, how do the new skin cells know to be discolored?

Posted: 07 Jul 2017 03:57 PM PDT

As you grow or get fat, your birthmark stretches. As it stretches, the boundary of the birthmark grows, and it gets filled in with new discolored skin. This doesn't seem to happen with moles for example. How exactly do discolored birthmarks expand?

submitted by /u/curdricelife
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Why does light travel a longer distance through different medium?

Posted: 07 Jul 2017 12:25 PM PDT

I learnt that light doesn't actually change its speed in a medium that makes it seem like it slows down, instead it only makes it travel a longer route? How does it do that? and why?

submitted by /u/alexbatman
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What causes medication stored outside its ideal temperature range to go bad?

Posted: 07 Jul 2017 10:44 PM PDT

Given sufficient computing power, how accurately could we theoretically predict how an organism would look and act based solely on a genome?

Posted: 07 Jul 2017 09:08 PM PDT

Why are particle accelerators like the Large Hadron Collider in Europe built underground?

Posted: 07 Jul 2017 04:16 PM PDT

I imagine that particle accelerators would be a lot cheaper and easier to build if they were above ground.

submitted by /u/esmivida
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How has the understanding of exoplanets changed since the first were detected in 1988?

Posted: 07 Jul 2017 11:56 AM PDT

How strong are the magnetic fields of stars?

Posted: 07 Jul 2017 08:30 PM PDT

In terms of Tesla (I think that's the correct measurement), how strong are the magnetic fields of stars? Neutron stars tend to have very strong magnetic fields, but what about other star types such as main sequence stars of varying masses?

submitted by /u/SyzygySoldier
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How much energy does a surge protector take up, considering that it's not technically an appliance but still draws power? Also, if I push the switch to off, will it still consume energy and show up on my electric bill?

Posted: 07 Jul 2017 02:29 PM PDT

Are there actually any benefits to using a surge protector other than having more outlets and protecting against a blackout?

Also, if I leave my surge protector plugged in with my PC plugged into it but the PC is powered off, will energy consumption be the same or more as opposed to not using the surge protector at all and opting to having a turned off PC in a wall outlet instead?

submitted by /u/ejayshun
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While forging metal, what would happen to the metal if you introduced high frequency vibrations to the metal while it's still in its liquid form, all the way until its cooled off? Would the characteristics of said metal change?

Posted: 07 Jul 2017 05:32 PM PDT

Any feedback would be much appreciated

submitted by /u/WHdrazzineddi
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Is it possible for humans to undergo a slower rate of development in puberty?

Posted: 07 Jul 2017 08:56 PM PDT

Sorry not sure if right place to post. Just to be clear I'm not talking about being a 'late bloomer' where an individual hits puberty at a later age but instead an individual who may hit puberty at a similar time to others but undergo changes associated with puberty at a slower rate.

submitted by /u/Asdfghjkl12345qw
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I have heard that CO2 is a green house gas as it locks heat in. How does it lock heat in on the atomic level?

Posted: 07 Jul 2017 10:51 AM PDT

How come we aren't effected by how fast the earth is spinning?

Posted: 07 Jul 2017 07:44 PM PDT

It seems like if a ball is spinning, something aboard it would fly off of it. Is the gravity of Earth strong enough to pull us back? So if the earth were to stop spinning gravity would get stronger?

submitted by /u/Parkachu0
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Why are some SI units like the ampere, sievert and farad so large?

Posted: 07 Jul 2017 01:38 PM PDT

Sorry if this is a silly question. It seems like some of the SI units are incredibly large.

submitted by /u/Jagar0th
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Why is it so hard to develop new antibiotics?

Posted: 07 Jul 2017 07:23 PM PDT

News about a gonorrhea superbug kind of freaked me out. And as far as I know humanity hasn't developed new antibiotics in over 25 years.

submitted by /u/Chuckknock
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When it's said that "a photon can be both a wave and particle at the same time", are the waves in the photon field from QFT?

Posted: 07 Jul 2017 02:35 PM PDT

So in QFT, a photon would be a disturbance in the photon field. Would these disturbances create the interference patterns that create the quantum-mechanic effects that we attribute to "the wave-like nature" of things like photons in e.g. the Double-Slit experiment? How sure are we that QFT is actually correct, and wouldn't it contradict the idea of the String Theories of each particle being the same basic object but vibrating in different ways (I may be chatting shit with that description, or in total)?

submitted by /u/BaconWraith
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Can stable baryonic matter other than protons and neutrons exist?

Posted: 07 Jul 2017 12:26 PM PDT

The recent CERN announcement where they verified the existence of yet another composite particle as predicted by the standard model had me thinking. Is there any possible configuration of quarks, other than the combination that results in protons and neutrons, that gives you stable (lets say half life > 1 second) matter under standard conditions (Earth-like temperatures/pressures)? If not, why not?

Another question in a similar vein: Is it possible (according to the known laws of physics, i.e. standard model) for there to be solid, as in, interacts electromagnetically with normal stuff, non-baryonic matter? I'm picturing something like a glob of gluons or hard light.

submitted by /u/Iwanttolink
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Do scarecrows actually work on birds, or is it obvious to them that those are just lifeless pieces of cloth or other material?

Posted: 07 Jul 2017 05:33 AM PDT

What are the minimum number of instructions a CPU would need to support to be Turing Complete?

Posted: 07 Jul 2017 08:36 AM PDT
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Friday, July 7, 2017

What were the oceanic winds and currents like when the earth's continents were Pangea?

What were the oceanic winds and currents like when the earth's continents were Pangea?

What were the oceanic winds and currents like when the earth's continents were Pangea?

Posted: 06 Jul 2017 08:49 PM PDT

How come a room doesn't get brighter the longer you shine a light in it?

Posted: 06 Jul 2017 09:32 PM PDT

If I turn on a lamp or a flashlight or something in an enclosed space, the photons fill the room. But if I keep the light on, then it keeps emitting photons, so why doesn't the room just keep getting brighter? Does it have to do with how fast photons decay?

submitted by /u/chinchillada
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Why is it easy to balance on a bike while moving, but hard while it isn't moving?

Posted: 06 Jul 2017 07:21 PM PDT

Does practicing throwing a ball accurately with your right hand increase your accuracy with your left hand and vice-versa?

Posted: 07 Jul 2017 02:50 AM PDT

What do old insects die of?

Posted: 06 Jul 2017 01:57 PM PDT

If humans who die of old age generally die of heart failure or cancer, what do old insects die of? I know the mayfly is supposed to live for a day, and that some spiders can live for years- but what actually kills them?

submitted by /u/imnotsurethatsnotok
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Why is stable matter only composed of protons, neutrons, and electrons? Why aren't there other stable combinations of elementary particles?

Posted: 06 Jul 2017 11:26 PM PDT

I'm aware that the earth is not a "sphere", but, rather, a heptoloidal zircosumfered something or another, however, the Sun sure seems to be very nearly spherical to me. Is it or is it not, and why, in either case?

Posted: 06 Jul 2017 08:19 PM PDT

When the super ocean Panthalassa existed, was there islands or archipelagos in the way we have them now?

Posted: 07 Jul 2017 03:48 AM PDT

Is there any evidence of a "prehistoric Galapagos".

submitted by /u/bonzkid
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Why do earthquakes have epicenters instead of an earthquake line along the plates that shift?

Posted: 06 Jul 2017 10:45 PM PDT

Why is fibreglass used at all in composite aircraft instead of being completely carbon fibre such as in the Boeing 787 ?

Posted: 07 Jul 2017 07:21 AM PDT

Carbon fibre is superior right? Are there any advantages or is it due to cost or construction difficulties? Here is a link to the materials used in the 787 http://technicallyspeaking.brachiolopemedia.com/wp-content/uploads/2013/08/CompositeMaterialsIn787.jpg

submitted by /u/tnfei
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Is it possible to heat an object through light such that it ends up being hotter than the source using only black body radiation?

Posted: 07 Jul 2017 03:32 AM PDT

I think this question (in various forms) has been asked to death but I've yet found any satisfying answers. XKCD has a piece on a similar question which resulted in a bunch of debate (for example here, here ).

But I'd like to concentrate on the main question stated in the title of this post since I think this is already hard enough to answer without being distracted by things like ignition points, practical losses by absorption of light in the atmosphere or trying to fit a mirror around the sun.

I have 2 situations in particular:

Say a photon is emitted of a (relatively) cold object. This photon then collides with a hot object. Why wouldn't this photon be absorbed by the hot object (and making it hotter)? The 2nd law of thermodynamics is often mentioned. Heat cannot flow from a cold object to a hot object. But is this still applicable if you are using light for the energy transfer? How would an emitted photon know how hot it's source was and why/how would it be prevented being absorbed by a hotter object? A photon is a photon right?

The second situation:

You could also think about the following (theoretical) set-up: 2 perfectly absorbing and irradiating black bodies placed at the focal points of an ellipsoid perfect mirror.

Both bodies will be at an equilibrium when left alone long enough. The equilibrium could be described by the Stefan-Boltzman Law. Which would result in the following formula:

A₁*T₁⁴=A₂*T₂⁴

And if the surface areas (A₁ and A₂) are not equal then the result would be that the temperatures (T₁ and T₂) are also not equal.

My gut feeling says "of course this is not possible" but I cannot poke a hole through these two situations I've just described. I'd love to hear your theories on this.

submitted by /u/yourfavoritemusician
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What causes ice cream to melt slower than gelato?

Posted: 06 Jul 2017 10:03 PM PDT

Why can't refrigeration create energy?

Posted: 06 Jul 2017 09:03 PM PDT

If heat is energy, and cold is the lack of heat, and refrigerators/freezers remove heat from food- why are they not self sustaining or using the heat they remove to create more energy/power

submitted by /u/K8H20
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How easy is it for electricity to arc in a vacuum?

Posted: 06 Jul 2017 02:20 PM PDT

I'm doing a project that's going to involve running a bunch of electronics in a near vacuum. Unfortunately I have basically zero experience working in a vacuum. I've done my best to account for a lot of the factors that could affect the circuit based on what I've been reading, but my big concern is that I need a kill switch that will physically disconnect power from the circuit controlling a set of 12V motors while it's being pressed. I've found a number of normally closed buttons that would work under regular conditions, but my concern is that the voltage can just arc across the leads in the switch even if it's opened once it's in the vacuum. Realistically, is this something I will likely need to worry about, or is there an equation that can give me an idea of whether or not arcing is likely?

If you need more info. The switch is going to be connecting a 12V battery to a circuit, and the physical action that's going to press the switch is at most an inch. I'll have electronic measures as a backup, but ideally I would like to be able to physically cut the power.

submitted by /u/TheSoup05
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Did earthquakes have a higher or lower magnitude when the continents formed Pangea?

Posted: 07 Jul 2017 03:48 AM PDT

What prevents certain drugs from permeating the blood brain barrier?

Posted: 06 Jul 2017 08:02 AM PDT

I hear about drugs not being able to reach the brain because they're filtered out by the blood brain barrier. What's going on to prevent this in certain drugs? Is it the size of the chemical or how it binds with proteins in the blood?

submitted by /u/Dancing_Hispanic_Cat
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How does antimatter interact with matter?

Posted: 06 Jul 2017 08:47 PM PDT

Since nothing actually touches each other and is just repelled by elctromagnetic forces unless they under go fussion how does antimatter interact to explode? Does it happen by the electromagnetism, it needs to fuse with matter or some other process?

submitted by /u/ExBrick
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What's the spatial structure of a single photon? Does it have a spatial amplitude?

Posted: 06 Jul 2017 11:57 AM PDT

So, like any particle field, photons have a complex amplitude, which in one dimension oscillates in size. Does a photon in three dimensions also have a spatial amplitude? Does it actually move up and down (or side to side), or is the oscillation of a photon purely in its wave function along a straight line?

submitted by /u/sgt_zarathustra
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If a & b are irrational must a+b be irrational?

Posted: 06 Jul 2017 09:46 AM PDT

Yesterday I stumbled across a dumb little "Only 10% of people get this right!" problem on Facebook:

√x + √(x+15) = 15

My solution was simple: I assumed that x and (x+15) were both perfect squares, and given that the distance between the nth and nth+1 perfect square is always 2n+1, it was immediately obvious that n=7 and x was 49. No big deal, not a hard problem.

However, it occurred to me my solution involved a weird postulate. That √x and √(x+15) must be perfect squares. As if there's no imperfect squares (if there is such a thing) the irrational roots of which could sum to the rational number 15.

So here's my question: Is it possible for 2 irrational numbers to sum to a rational number? And let's disqualify the obvious degenerate case where the irrational parts of the number cancel out, like if:

  • a = 2 + √2
  • b = 2 - √2

Yeah, obviously their sum is rational. But what I'm really asking is you could sum just the irrational bits, much like we do with imaginary numbers, if it's possible to make a rational number. My intuition says no, it's not possible. Is there a proof?

submitted by /u/garrettj100
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How do FM radios detect radio stations based on frequency if the whole concept of FM is to alter the frequency?

Posted: 06 Jul 2017 09:43 AM PDT

I started learning RF theory and I'm hung up on this concept of Frequency Modulation. I think theres a hole in my fundamental understanding.

If my radio locks onto say, 98.1, its listening for signals operating at 98.1 MHz. So if to create music or whatever else on the channel you have to modulate the frequency, doesnt that make it no longer 98.1?

I know I'm wrong since FM radios function, I ust wanna know how

submitted by /u/TearShitDown
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I live near the polar circle and I travel at a lower speed along with the Earth compared to my imaginary friend who lives on the Equator. Does the effects of this difference in speed on our bodies impact our lifespan or our physiology over our lifetimes?

Posted: 06 Jul 2017 09:08 AM PDT

How can WIMP detectors exist if WIMP's are hypothetical particles?

Posted: 06 Jul 2017 10:59 AM PDT

Weakly Interacting Massive Particles aren't even clearly defined, so designing an apparatus to detect them sounds impossible.

submitted by /u/FacepalmNation
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Thursday, July 6, 2017

What happens to the speed of photons emitted by a moving light source? Do they travel faster than the speed of light, c?

What happens to the speed of photons emitted by a moving light source? Do they travel faster than the speed of light, c?

What happens to the speed of photons emitted by a moving light source? Do they travel faster than the speed of light, c?

Posted: 06 Jul 2017 04:29 AM PDT

For animals with better hearing than humans, are sounds comparatively louder?

Posted: 05 Jul 2017 06:12 PM PDT

Are there cultural reasons behind SVO or SOV word orders in languages? Or is it just whatever stuck?

Posted: 06 Jul 2017 02:53 AM PDT

Why was I in a earthquake if I'm nowhere near a fault line?

Posted: 06 Jul 2017 12:21 AM PDT

Sorry if this a dumb question but I'm in northern Montana and if I recall...there are no fault lines near me.

submitted by /u/logan-mcneil
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How do Not Gates work?

Posted: 06 Jul 2017 02:42 AM PDT

I totally understand how OR and AND gates work in real life, but could someone explain the physical process involved in a Not gate?

I can only visualise a Redstone torch on top of a powered block :D

submitted by /u/MoreThanTom
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How can atomic orbitals be described as standing waves if they have no physical boundaries?

Posted: 05 Jul 2017 03:11 PM PDT

According to Orbital Theory atomic orbitals can be described as standing waves. Analogies such as vibrating strings or planes are often used to explain this.

What both these analogies have in common is that for a string or a plane to swing as a standing wave they need to have boundaries at which their amplitude is always zero. A string is bound by two nodes, in the simplest case a plane is bound by a circle.

Thus, for a wave in three dimensions I would expect a standing wave to require at least a sphere in which the amplitude is bound to be zero. However, with 1s orbitals in particular we observe no nodes whatsoever. In fact, the maths predicts that an electron occupying that orbital would have a non-zero probability of being detected anywhere. How is this still a standing wave?

submitted by /u/Xasmos
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What considerations or procedure is used to maintain correct orbit while thrusting to dock wit hthe ISS ISS?

Posted: 05 Jul 2017 06:33 PM PDT

When a capsule is reaching the ISS after phasing orbit, what effects do the final adjustments to get close to the iss have in orbital speed and altitude? Can they just point and shoot, or does that method bring them off course some how in the orbit path?

submitted by /u/darklegion412
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Does Polynomial interpolation work with n-1 times the same supporting point xi and 1 thats different?

Posted: 06 Jul 2017 02:57 AM PDT

first, english is not my mother language... so dont hate me too much.

So when i do polynomial interpolation, and i have n different supporting points, i can build a lagrange polynom(Li(x)) and do the standard interpolation fn(x) = sum(f(xi) *Li(x))

and if i have 1 supporting point, I could simply do a taylor approximation https://en.wikipedia.org/wiki/Taylor_series with n times the supporting point "a"

but what if i have n-1 times the same point a and 1times b?`

i learned that in general the system matrix that contains the base-funktions with the different supporting points, has to have full rank. so that i can get a unique solution, but why does it matter if i can solve it for 1solution i have a solution and dont have to care if ther are more?

submitted by /u/Glibglob12345
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How do humans counteract the Dzhanibekov effect (phenomenon responsible for the "Tennis Racket Theorem") when doing layout front and back flips? Shouldn't all human flips have at least half a twist?

Posted: 05 Jul 2017 03:30 PM PDT

Is there a non-geometric equivalent to Einstein's theory of general relativity?

Posted: 05 Jul 2017 11:13 AM PDT

If I understand correctly, the geometric approach is what makes this theory so elegant. I wonder if there exists a theory that takes a non-geometric approach and agrees with the general theory of relativity on all (or most) findings at the expense of simplicity.

EDIT: a bit more clarification after a deleted comment:

Define "non-geometric" in specific terms?

GR abandons the idea of gravity as a force instead treating it as space-time curvature. I suppose related to this is the formulation of the theory with the help of tensor analysis. So my question can be broken down into the following:

(1) is there a way to use some sort of heavily modified Newton's force approach on flat space-time to arrive at the same conclusions, and

(2) is there a way to formulate the theory in terms of something different than tensors (similar to how geometric vectors can be treated purely algebraically by creating a coordinate system).

submitted by /u/Im_int
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Can fog form in caves?

Posted: 05 Jul 2017 07:53 PM PDT

It's a common depiction in video games like Skyrim, but does it really happen? If so, how common is it? I imagine most caves don't have enough water.

submitted by /u/dmsub
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Does the expanding universe, in any sense, temper the gravitational effects of massive objects. In other words, does the expansion of the universe smooth out space-time at all?

Posted: 05 Jul 2017 09:44 PM PDT

What happens to whales and other ceteceans during a really violent storm/hurricane?

Posted: 05 Jul 2017 09:56 AM PDT

(I know this might be a stupid question, but hell i aint no biologist.) Can they get sufficient air when surfacing or do they have trouble breathing because of super-choppy water conditions? Anyone ever seen any research on this? Are there loads of dead whales and dolphins left in the wake of hurricanes?

(Posted this in r/showerthoughts earlier without much response)

submitted by /u/caseypb
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Are Immortal cell lines affected by telomeres shortening?

Posted: 05 Jul 2017 10:56 AM PDT

Wikipedia says: "An immortalised cell line is a population of cells from a multicellular organism which would normally not proliferate indefinitely but, due to mutation, have evaded normal cellular senescence and instead can keep undergoing division."

What are those mutations?, are they related to telomeres?, if not, how those telomere shortening affect this kinds of cells?

submitted by /u/Frigorifico
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Do birds sleep longer in the Winter?

Posted: 05 Jul 2017 08:08 PM PDT

Birds only "tweet" during daylight hours so if they are sleeping when it is dark does this mean they sleep longer during the extended darkness of Winter hours?

submitted by /u/twickky
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What is a precursor wave?

Posted: 05 Jul 2017 12:44 PM PDT

How does a precursor wave work? As I understand, during nuclear explosions there are different stages to the blast wave and one of them is a precursor wave, which travels faster than the main blast wave. Why does it travel faster from the main explosion shockwave?

submitted by /u/VONChrizz
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Does actual computing require energy?

Posted: 05 Jul 2017 09:20 PM PDT

What does the power supplied from the wall do other than heating up circuitry, spinning some fans and maybe lighting up some LEDs? Is power drawn from a chip completely turned into heat or does some of it magically disappear? I don't think the latter is true but some comments under some youtube videos make me question myself like "power drawn isnt equal to heat dissipated, there is efficiency, some power is used to run the gpu, blah". I concluded that electronic computers without lights or mechanical parts are physically literally %100 efficient space heaters, is this true?

Edit: I know how computers work mathematically, just the conservation of energy didn't add up. I thought: Power in = resistive heat loss + friction heat loss from fans + fan kinetic energy + lights +??

?? Turns out to be switching transistors requiring potential energy to store the current state

Thanks for the downvotes also

submitted by /u/bevkcan
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