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Thursday, May 18, 2017

They say that to test String Theory, we need to build a particle accelerator as large as out galaxy. Is it a technical limitation or a fundamental one?

They say that to test String Theory, we need to build a particle accelerator as large as out galaxy. Is it a technical limitation or a fundamental one?


They say that to test String Theory, we need to build a particle accelerator as large as out galaxy. Is it a technical limitation or a fundamental one?

Posted: 17 May 2017 10:09 AM PDT

Why do I feel like I need to cough when I stick a q-tip in my ear?

Posted: 17 May 2017 01:32 PM PDT

I know you're not supposed to do it, but I still do. When I stick a Q-tip in my ear, I get this overwhelming urge to cough. Why is that?

submitted by /u/Rottendog
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Why do we have to kill a horse when it broke its leg? What is the difference in biological processes between man and horse in bone mending?

Posted: 18 May 2017 03:12 AM PDT

How dangerous is uranium/uranium oxide to handle?

Posted: 17 May 2017 08:40 AM PDT

At 38:55 of the below video, it is said that people wear gloves when handling uranium to protect the uranium from being contaminated, rather than wearing gloves to protect themselves from the uranium. It is said that since uranium's half-life is in the billions of years, it isn't that radioactive.

This sounds hard for me to believe, as I thought uranium was very dangerous to handle. Is it true that uranium isn't that radioactive? That gloves are worn to protect the uranium, and not the human?

Also, is uranium oxide - which is what the pellets in the video are - the same as uranium in terms of safety?

https://youtu.be/H6mhw-CNxaE

submitted by /u/Fyreborn
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Light beam propulsion without lasers?

Posted: 18 May 2017 05:57 AM PDT

We now have the capability to do laser launch. The problem is the initial cost outlay for the lasers is still prohibitive to launch a sizable payload.

The estimate of the payload you can launch to Earth orbit dependent on laser power is about 1 kg per megawatt. So to launch thousand kilo payloads would require a gigawatt laser power levels. At current prices this would cost billions of dollars.

But is it possible to do it without using lasers, just using high intensity noncoherent light focused by mirrors or lenses?

I wondered about this because of two reports I saw doing a web search actually on optical communication:

InfiniLED MicroLEDs achieve 300 W/cm2 output density from tiny source. The MicroLEDs semiconductor manufacturing process includes construction of a parabolic reflector to enable optimal light control and high efficiency from micro-meter-sized LEDs. Published on:Jan 29, 2013 By Maury Wright

http://www.ledsmagazine.com/articles/2013/01/infiniled-microleds-achieve-300-w-cm-sup-2-sup-output-density-from-tiny-source.html

and:

Optical communications using coherent and non-coherent light.

http://modulatedlight.org/optical_comms/optical_about.html

The first report discusses micro-scale LED's whose light output scales up to 300 W per square centimeter, 3 megawatts per meter. From the appearance of these micro-scale LED's, they should permit simple automated production to produce many copies to cover a macro-scale area to generate light even at gigawatt power levels.

The second report discusses experimentation that suggests atmospheric dispersion is actually worse for lasers than for noncoherent light generated by LED's. See for instance the video in Fig. 2 on this page.

The advantage of the lasers however is that generating a parallel beam, you can use a parabolic mirror to focus the light at the focal point (more precisely at the Airy disk). Still, nevertheless a parabolic mirror will still focus a large portion of the light at the focal point even for noncoherent light.

So the question is if the beam is noncoherent, how much of the light can still be focused at the focal point (Airy disk)?

submitted by /u/RGregoryClark
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Why does boiling water make so much sound?

Posted: 18 May 2017 03:52 AM PDT

Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

Posted: 17 May 2017 08:04 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Biology, Chemistry, Neuroscience, Medicine, Psychology

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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Where do prions originate from?

Posted: 17 May 2017 08:53 PM PDT

Can air "hold" alcohol (ethanol) like it can water at room temperature?

Posted: 17 May 2017 08:30 PM PDT

Hey guys. I know this question highly depends on the temperate and probably air pressure or something, so lets say typical summer day, 25°C (=77°F or 298,15°K), normal pressure. I place a bowl of pure alcohol in a room. Will alcohol "go" into the air like water would?

(Sorry for the words in "", I'm from germany and english isn't my native language so i was missing a few vocabularies :> )

submitted by /u/Truckermouse
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Can we only detect planets in systems that we see edge on?

Posted: 17 May 2017 05:13 PM PDT

I've heard that we use the transit method for identifying planets passing in front of stars. Does this mean that we can only detect planets if their orbital plane is along our line of sight?

submitted by /u/nyxo1
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If you stacked a lot of microscopic organisms, would you eventually be able to see them? What would they look like?

Posted: 17 May 2017 07:28 PM PDT

Assuming they don't move or run away, what would happen if you stacked (or piled up) a lot of microscopic organismic or just microscopic "things" in general. Disregarding the improbability/impossibility of finding that many of the organism, would you eventually pile up enough to be able to see them? Would it look like a solid mass?

Bonus: what would it feel like?

submitted by /u/DasBeasto
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Why should death from dehydration have to be so suffering?

Posted: 17 May 2017 07:12 PM PDT

I have heard that dying from dehydration is one of the most uncomfortable and gruesome death possible. I understand some aspects on why a person would show symptoms because it is the body's way of warning the user. However, if a person is severely dehydrated then the body should just accept that the person is probably stuck somewhere that has no water. The body should release large amount of endorphin and make the death as serene and comfortable as possible instead of having the person suffer through death.

I do not understand this from a biological standpoint since starvation has the body release endorphins after a while since it recognizes that death is inevitable.

submitted by /u/Grandtier
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What happens on an atomic scale when water is boiled?

Posted: 17 May 2017 11:55 AM PDT

So my college entry biology professor (with a doctorate) just told my summer school class that when water boils, the hydrogen and oxygen atoms split and bind to each other, forming H2 and O2. I have always been taught that water vapor is just water molecules that are heated to a gaseous form.

Also, if what he said is true (which at this point, I have trouble believing) than why does the ensuing H2 gas and O2 gas not react with my kitchen stove and blow my house apart when I do something like cook pasta?

submitted by /u/scarredFalconer
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Use of the delta function in QM?

Posted: 18 May 2017 04:44 AM PDT

I've only ever come across this function in Control Engineering for system response, however I think I remember someone in another thread mentioning its use in quantum mechanics, can anyone tell me how it is used in that field?

Thanks

submitted by /u/spk96
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[Physics] How do whispering gallery mode resonators in lasers work?

Posted: 18 May 2017 04:31 AM PDT

How do they work and how are they able to get ultra narrow linewidth, high Q factor? Links to articles, journals or books are highly appreciated. Thanks in advance.

submitted by /u/Quanta314
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how does chirality come into play when manufacturing pharmaceuticals?

Posted: 17 May 2017 10:10 PM PDT

I understand what it is I just dont get how a mirror of a molecule would come into play. are they connected? do they come in pairs and the other molecule has to be flushed out? does it just happen by accident that a molecule chiral partner slips into the mix and isnt easily spotted because of its likeness? please explain.

submitted by /u/endlessunshine833
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How does the weak force works ?

Posted: 17 May 2017 11:53 PM PDT

I manage to understand the other 3 interaction but the weak force still remains a mystery, i was wondering if you van answers these following questions: 1. What are the mechanism of the weak force ? 2. What field of boson transmit it ? 3. How does the weak force affect our lives ? 4. Can or Have we harnessed the weak force in any way ?

submitted by /u/Mikhail_Mifzal
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What makes some adhesives reusable and some useless unless reapplied?

Posted: 17 May 2017 06:53 PM PDT

In the case of sticky notes, they can be stuck several times before losing their "stick", while things like super glue stick once and never again.

submitted by /u/Unfortunate_taco
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If I aim a 'typical' laser-pointer into the night sky, assuming no clouds, how far will it travel/be detectable into space?

Posted: 17 May 2017 06:40 PM PDT

Obviously I know this depends on the sensitivity of the object "detecting it" but in general how far would a laser-pointer pointed into the sky get before it could no longer be detectable.

If it's necessary to put a metric on it "how far until the human eye would no longer notice its presence?"

submitted by /u/gett-itt
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Can swordfish see their own bill?

Posted: 17 May 2017 03:32 PM PDT

What in the human anatomy of fingers makes it easier to get a ring on than off?

Posted: 17 May 2017 11:17 AM PDT

Wednesday, May 17, 2017

Why do so many medicines require you to stop eating grapefruit?

Why do so many medicines require you to stop eating grapefruit?


Why do so many medicines require you to stop eating grapefruit?

Posted: 16 May 2017 02:03 PM PDT

Is a single atom able to cast a shadow?

Posted: 17 May 2017 03:24 AM PDT

[neuroscience]Is there any limit as to how much information that the human brain can hold?

Posted: 16 May 2017 06:58 PM PDT

Is there any theoretical limit as to how much information that the human brain can hold?

What would happen if someone reached that limit?

submitted by /u/Der_Ist
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Why is NASA's James Webb telescope built out of hexagonal panels for its mirror? Why is the mirror not a curved surface, and why were hexagons chosen over triangles or octagons etc.? Why does the Hubble telescope (seem to) not require this geometry?

Posted: 16 May 2017 10:02 PM PDT

Why is there a blip in lift at the stall angle in this CFD calculation?

Posted: 17 May 2017 03:55 AM PDT

As you can see from this image, there is a blip in lift around the stall angle for the wing we ran through a CFD program. We tested around 17-20 degrees multiple times and still saw that the lift went down, then up, then dropped off again as it stalled.

Is there a reason for the lift dropping off, then spiking again? Is it because of something to do with the flow detaching at a certain angle, then managing to reattach before detaching again? Is it just an expected error when running this sort of simulation through a computer program, or did we simply not test a wide enough range around the stall angle to get enough data to show a relatively steady drop off?

Lots of questions, I'm just puzzled as to why this happened. Any help would be greatly appreciated!

EDIT: My comment on a x-post:

Yeah, vortices being generated on the leading edge would be my guess as it's the only seemingly possible way for the flow to reattach after detaching at a slightly lower AoA, which would explain the lift spike.

The only comparable example I can come up with is the Vortex Lift effect on delta wings, which causes an increase in lift at high AoA due to vortices forming on the leading edge. However, this happens because the leading edge is sharp, so I didn't think this was possible for a ~NACA 0021 profile.

For delta wings: "In general, this vortex flow results in an increase in lift associated with the upper-surface pressures induced by the vortex and an increase in drag resulting from the loss of leading-edge suction." The effect is how delta wings maintain low speeds / high AoA as the vortices increase the stall angle.

No way of testing it, but it's a NACA 0021 profile so I thought that this effect would be well documented if it existed on the profile. The only reason I can think it might not be documented is if this effect only happens at certain airspeeds and I happened to pick one that it does happen at.

It may just be an error with the CFD calculations, or it's just such a small effect that it's not credited elsewhere.

submitted by /u/Geotherm_alt
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How do virtual photons have a real influence?

Posted: 17 May 2017 06:00 AM PDT

My question is, if virtual photons are a mathematical book keeping tool, how do they play a real role in terms of Hawking radiation and vacuum energy?

Thanks!

submitted by /u/spk96
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Has an underground nuclear power plant ever been attempted, and would having a nuclear plant under ground mitigate the problems from a meltdown?

Posted: 16 May 2017 02:36 PM PDT

Can a linear accelerator be re-configured and used as a 'decelerator'?

Posted: 16 May 2017 06:23 PM PDT

Let's say one had a beam of charged particles moving at some speed, could they be slowed using a linear accelerator that is reconfigured to decelerate the particles? If it's simpler to think about this with defined 'packets' of charged particles, or particles that penetrate the 'decelerator' one at a time, then so be it.

submitted by /u/dbcollins
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Can neutrons be created by bombarding protons with electrons of high enough energy?

Posted: 16 May 2017 10:19 PM PDT

I'm aware that electron capture is this process, but it only occurs in nuclei where there is a lower energy decay state. What I haven't been able to find information on is if it's possible to fire an electron at a proton and convert the pair into an electron neutrino and neutron via the weak interaction, provided that the electron comes in with enough kinetic energy to account for the extra neutron mass. Since a similar process can take place with neutrinos transforming protons in nuclei via inverse beta decay, can electrons do something similar to bare protons (Hydrogen)?

submitted by /u/USI-9080
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Do different types of radiation have different effects?

Posted: 16 May 2017 04:56 PM PDT

I work in a nuclear power plant and we hear a lot about radiation doses and everything we do to keep it as low as reasonably achievable (ALARA).

During our training that everyone goes through we learn about different types of radiation: alpha, beta, gamma, and neutron. The focus is primarily on their penetrating power. Alpha is stopped by paper or skin, beta is blocked by plastic or aluminum, gamma is blocked by lead, and neutron radiation is blocked by concrete.

My question is do these different types of radiation have different effects on the body or are they just classified that way according to their shielding requirements?

submitted by /u/firedragonsrule
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Do astronauts in space have to push harder, in order to have a bowel movement?

Posted: 16 May 2017 06:30 PM PDT

If someone is walking down the road, is the air around them moving to avoid the person, or are they more like a knife cutting through the air?

Posted: 16 May 2017 12:28 PM PDT

Could a binary star system have a planet tidally locked to the baricenter?

Posted: 16 May 2017 02:48 PM PDT

What kills you when you burn to death?

Posted: 16 May 2017 12:46 PM PDT

Ok so the title sounds a bit silly but my question is,

What exactly is shutting down or ceasing to function when one burns to death? Obviously burning skin probably wouldn't kill you (not quickly anyway) and pain cant kill people AFAIK

So what is the fire doing to your body that causes you to die? is it heatstroke? does the fire burn through your skin and begin directly damaging organs? i was of the understanding fire killed you long before it was able to do this.

submitted by /u/ronduun
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If humans have only been around for about 100,000 years, then why did it take 95,000 years for us to do anything rememberable? Did our brains become more evolved in the last few thousand years?

Posted: 16 May 2017 07:49 PM PDT

The first major civilizations emerged around 5,000 years ago in places like the Middle East. All of recorded history fits approximately within the last 5,000-years. That leaves 95,000 of human history with nothing happening besides changes in the types of spears we used. Where are the wars of conquests and battles between the great empires from 50,000 years ago? Things like this didn't happen because it took 95,000 years to invent agriculture? Are humans from 50,000 years ago just the same as me? It seems amazing that for 95,000 years we did nothing, and just within the last 5,000 years we have gone from cave men to developing the technology to colonize other planets.

submitted by /u/some_dude_0123
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Why does being electrocuted (high voltage) cause a person to die?

Posted: 16 May 2017 08:58 PM PDT

In conversation with friends, we decided to look this up but after numerous pages on google, the most we got was that it stops your heart.

Why does it stop your heart? What prevents a human from being able to withstand higher voltage without dying?

Edit: grammar

submitted by /u/shirtlessaustin
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Can anyone give an intuitive explanation of gauge theory?

Posted: 16 May 2017 04:25 PM PDT

Is it possible to explain it in a way which is intuitive? I'm thinking something along the lines of how gravity is "an elastic sheet", but better than that, because that's a terrible analogy...

Thanks

submitted by /u/toolemeister
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[Physics] Can you fuse elementary particles and their antiparticles together, and what happens if you do?

Posted: 17 May 2017 04:51 AM PDT

I was wondering if you can fuse the following pairs: -Quarks/Antiquarks -Gluons/Antigluons -Electrons/Positrons

Do you still get a Photon for all of them or do you get a new particle. If you get a Photon, how could you create a new particle instead of a Photon?

I'm guessing that they have to collide to release their energy as Photons.

submitted by /u/Fleeingfromhumanity
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Is there an intuitive way of understanding the contraction mapping theorem?

Posted: 16 May 2017 05:59 PM PDT

How stable would elements in the island of stability be?

Posted: 16 May 2017 03:46 PM PDT

I'm asking because its my understanding that most superheavy elements last for inconceivably short amounts of time. Is it plausible that elements in the island can exist for thousands of years, or may it only be for a few seconds at best?

Following on, is there a possibility elements in the island could occur naturally somewhere in the universe?

submitted by /u/Khwarezm
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Could someone explain these equations?

Posted: 17 May 2017 02:41 AM PDT

Tuesday, May 16, 2017

AskScience AMA Series: We are astrophysicists who translated the motions of seven Earth-sized planets in the TRAPPIST-1 system into music. Ask Us Anything!

AskScience AMA Series: We are astrophysicists who translated the motions of seven Earth-sized planets in the TRAPPIST-1 system into music. Ask Us Anything!


AskScience AMA Series: We are astrophysicists who translated the motions of seven Earth-sized planets in the TRAPPIST-1 system into music. Ask Us Anything!

Posted: 16 May 2017 05:00 AM PDT

Check out this short animation about the music of the TRAPPIST-1 planets: https://www.youtube.com/watch?v=7i8Urhbd6eI

TRAPPIST-1 is a prime candidate in the search for life beyond our solar system. It is one of the 300 closest stars to us, and hosts seven Earth-sized planets, several of which might have the right temperatures to host liquid water. It also has a remarkably precise orbital configuration. For every 2 times the outermost planet goes around the central star, the progressively interior planets each execute almost exactly 3, 4, 6, 9, 15 and 24 orbits. Such a long so-called resonant chain is unprecedented.

We recently translated these rhythmic planetary motions into music. We also assigned planets notes by scaling up their orbital frequencies into the human hearing range. The result is remarkably harmonious thanks to the near-perfect period ratios between planets. You can learn more and experience the awful cacophony generated by more normal systems at http://www.system-sounds.com.

One puzzle that has loomed since the discovery of TRAPPIST-1 is how such a tightly spaced system of planets can avoid destroying itself due to repeated gravitational tugs. Our research has revealed a solution that relies on the same harmonic pattern responsible for creating such beautiful music.

Thought Cafe, the animation team behind the video is also joining us.

We'll be on around 3:30 PM ET (19:30 UT). Ask Us Anything!

submitted by /u/AskScienceModerator
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Is it likely that elements 119 and 120 already exist from some astronomical event?

Posted: 15 May 2017 12:31 PM PDT

I learned recently that elements 119 and 120 are being attempted by a few teams around the world. Is it possible these elements have already existed in the universe due to some high energy event and if so is there a way we could observe yet to be created (on earth) elements?

submitted by /u/Beaverchief62
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What is actually happening when I hear my timber framed house 'crack'?

Posted: 16 May 2017 01:27 AM PDT

I understand that heating and cooling is responsible for it but are tiny cracks actually being made every time I hear it?

submitted by /u/Dallasrallas
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What would happen to the structure of a radioactive diamond as it decays?

Posted: 16 May 2017 03:08 AM PDT

For a diamond made entirely of carbon-14, which I understand undergoes beta minus decay into nitrogen-14, what will happen to its tetrahedrally bonded structure as individual carbon atoms decay, and are replaced by nitrogen atoms?

One idea I had was that the nitrogen escaped the structure leaving gaps in the lattice. If this occurs, would the diamond then conduct electricity, (given a significant proportion of the carbon had decayed) since some carbon atoms will be only bonded to 3 others, and will therefore have free electrons, similar to graphite?

Also, if the nitrogen were to escape, would it have to form nitrogen molecules as it does so (and therefore two adjacent carbon atoms would have to had decayed?), or would it leave the structure as singular nitrogen atoms?

Finally, could the nitrogen remain tetrahedrally bonded in the structure (forming four bonds to adjacent atoms rather than the usual three)? If so, after all of the atoms have decayed, what would you be left with?

Bonus question: would a diamond made of carbon-14 look any different to a regular diamond, i.e. refract light any differently?

Sorry this question is so long, but I'd be interested to find out what occurs, or if I have misunderstood the idea completely.

submitted by /u/xkimlam
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If fire needs oxygen as fuel then how do rockets work in space?

Posted: 15 May 2017 05:31 PM PDT

Why do we care about the heavy elements like 119 and 120 that decay in like .00002 seconds? What could we possibly use it for?

Posted: 15 May 2017 10:33 PM PDT

why do we care tho? to prove we can?

submitted by /u/KyubeyTheSpaceFerret
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What is the difference between the frequentist and the Bayesian meaning of probability?

Posted: 15 May 2017 05:00 PM PDT

Why do faucets hiss at specific levels of valve-openness, which seem random and nonlinear?

Posted: 16 May 2017 01:04 AM PDT

It seems really unusual - when the faucet is barely open, it doesn't produce the sound, and it doesn't do so when it is fully open. However, at about 1/4 and 3/4 open (but not at 1/2), there are two levels when it produces a loud hissing sound. How can this be explained? Why is the pattern so nonlinear? Is this something about turbulence?

submitted by /u/contravariant_
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Why does the weak force have two force mediators when the other 3 fundamental forces have one?

Posted: 16 May 2017 04:31 AM PDT

The strong force has gluons, the electromagnetic has photons, and the gravitational (hopefully) has gravitons. So why is it that the weak force has both W-bosons and Z-bosons?

also: While we're on the topic of fields, what are fermionic fields and dirac fields, what physicality do they describe?

submitted by /u/ultramadscienti
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Why can't the Great Barrier Reef be repopulated?

Posted: 15 May 2017 01:33 PM PDT

I am not discounting the problem of coal bleaching and I've seen the pictures.

I realize evolution takes a while, so the natural corals in place can't keep up to their environments' changing, but if coral grow in all different environments and depths through the world, why can't marine biologists engineer new, more heat-hardy algae and coral then stimulate them to grow in the dead reefs?

I'm sure I'm not the first person to think of this, so what's standing in the way? Why is there this upper limit on temperature when there doesn't seem to be a lower limit, since corals can grow deeper?

submitted by /u/Shillarys_Clit
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Is there any weird phenomenon related to the non-existence of the mean of the Cauchy Distribution?

Posted: 16 May 2017 05:15 AM PDT

I understand how to prove that the mean doesn't exist, but it still feels weird. Is there any interesting mathematical reason for that? I've also read that it appears in physics too. Is there any weird phenomenon related to the non.existence of the mean?

submitted by /u/Dash218
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Are quantum entangled particles subject to time dilation?

Posted: 15 May 2017 08:28 AM PDT

Let's suppose you have two twin astronauts as described in the Twin Paradox thought experiment. Each of them is given one particle of a quantum entangled pair for safekeeping. One twin remains on Earth, while the other flies away for several years traveling at nearly the speed of light. When he returns to Earth he is younger than his brother. The entangled particles have experienced the same effect as the brothers have, and are brought back together. Are the particles both still entangled in the same time reference to one another? If you collapsed the wave function of one particle would the other "end" collapse at the same time, or would it seem to happen with some sort of delay in relation to the time dilation effect that had been imposed?

submitted by /u/wavy9944
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How does the flowregulator on an IV-drip influence pressure beyond said flowregulator? None of my docters can give me a straight answer. Physics-question, not medical.

Posted: 15 May 2017 11:58 AM PDT

Non-english speaking. I work in urology. Lately the nurses have had a discussion about flowrate and pressure. I'll try to keep the medical parts of my question simple because this is mainly a physics-question.

A patiënt of ours has a drain in his kidney. Basically it's a tube into the plumbing of the kidney. http://patients.uroweb.org/fileadmin/eau_images/images_full/percutaneous-nephrostomy.jpg Mr. X needs to get chemo through this drain to battle cancer inside of his pyelum and ureter (his kidneyplumbing).

The higher you hang the IV-bag with chemo, the higher the pressure in the line, the higher the pressure in his kidney. High pressure is BAD for kidneys. Therefore the guidelines state that the IV-bag shouldnt be hung to high (40-50cm max).

At half length there is a flowregulator. http://www.thrivingpets.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/v/iv_set.gif

It's a little wheel that you can adjust to vary the amount of drops that fall into the dripchamber. Assume the lower half of the line stays at the same height and the amount of fluidpressure doesnt change due to an emptying IV-bag.

If the IV is hung twice as high but the flowregulator is squeezed so tight that the flowrate (amount of drips) stays the same. Doesnt that mean that the pressure beyond the flowregulator is the same in both instances?

Edit: spelling (ofcourse), plus assume the pressure inside the kidney stays the same too. The question is pure about the IV-line.

submitted by /u/Critical-Case
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What are Lagrangian and Hamiltonian mechanics in a simple sense? Also, why would you use them?

Posted: 15 May 2017 05:01 PM PDT

I looked it up and tried to understand it and I kind of get Lagrangian but not Hamiltonian in the slightest.

With Lagrangian mechanics: What is the generalized force? Also, what are you actually solving for?

With Hamiltonian: Basically what is this? Any examples that would be easy to follow?

Thanks in advance

submitted by /u/redguy39
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Why do some trees have purple leaves?

Posted: 16 May 2017 05:15 AM PDT

I understand that most trees are green because of chlorophyll etc, but why do some trees have purple leaves instead of green ones?

submitted by /u/_Callen
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Why does interacting with a radioactive element (on a quantum level) prevent that element from decaying?

Posted: 15 May 2017 07:25 PM PDT

I noticed this a few times in different articles. Most recently in an article about transmitting information without particle exchange (via light wave phase). They said that measuring/interacting with the element suppresses its radioactive decay.

How/why does this happen? Does this mean that you can indefinitely keep a radioactive element from decaying? For days, months, years? Even the super heavies which usually decay almost instantly?

submitted by /u/chipstastegood
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Does infinity naturally occur physically in the universe?

Posted: 15 May 2017 05:09 PM PDT

Is there any evidence that shows something goes to infinity in nature? Like there is infinite time, or infinite space in the universe?

If there is no evidence suggesting that, does that mean there may be a finite amount of time or space? What would be the implications of that?

submitted by /u/trev-dogg
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What is the physics behind the sound two things make when they are brought together (usually with force) and why does more rigidity in the objects lead to greater volume in this sound?

Posted: 15 May 2017 04:28 PM PDT

[Chemistry] On a molecular level, what makes a sharp object, well, sharp?

Posted: 15 May 2017 10:49 AM PDT

Is there a way to tell if a large piece of structural steel is in compression or tension without damaging it?

Posted: 15 May 2017 08:31 AM PDT

Having a discussion with my SO and we couldn't get a satisfactory answer to this one. She's a structural engineer, and at one of her projects there's a mysterious (and very large) steel prop which seems to be holding up a building. They can't remove or replace it without knowing whether it's in tension or compression... but they don't know how to find out which.

Would the conductivity of a steel change if it's in tension or compression?

submitted by /u/DugTheDog
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How does H₂ Pd/C "cut" a benzene completely away from a carbon bond?

Posted: 16 May 2017 12:04 AM PDT

Ok so I'm an organic chemistry undergraduate and out professor challenged us wit a graduate problem. I know H₂ Pd/C breaks double bonds apart but with a benzene ring attached to a carbon group (BnO-R to be specific) why does it break the benzene completely away from the O-R group? Why not just take out all the double bonds in benzene and make it a simple cyclohexane?

submitted by /u/20needHelpPlease
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What is it about some materials, such as wool, that traps heat very well?

Posted: 15 May 2017 07:53 PM PDT

What is Zero point energy?

Posted: 15 May 2017 12:34 PM PDT

So what is zero point energy and what can it be used for? I see definitions all the time but I just don't know what they mean. So if someone can simplify the definition as best as possible for me, I would be really appreciate it.

submitted by /u/WhiteSox1415
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How do proteasome inhibitors help cancer patients?

Posted: 15 May 2017 11:26 PM PDT

If cancer cells divide rapidly and create misfolded proteins and antibodies, then how does it help to inhibit the protein which breaks these misfolded proteins down?

submitted by /u/paulgrylls
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