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Friday, June 3, 2016

Photons are massless, but yet possess some energy, can this energy be converted to mass? Can a photon become to a piece of mass at some circumstances?

Photons are massless, but yet possess some energy, can this energy be converted to mass? Can a photon become to a piece of mass at some circumstances?


Photons are massless, but yet possess some energy, can this energy be converted to mass? Can a photon become to a piece of mass at some circumstances?

Posted: 03 Jun 2016 04:37 AM PDT

Is the sun a black body?

Posted: 02 Jun 2016 09:09 PM PDT

I know this is in an idealized context, but I've seen the sun described as a black body before. Does that mean it's in thermal equilibrium if it emits black body radiation?

submitted by /u/PolymorphicWolf
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Have we ever observed quantum behaviour on a macro scale?

Posted: 02 Jun 2016 03:25 PM PDT

I know about the famous slit experiment, but I was wondering if there are any other interesting examples. I heard that scientists somewhere got a whole gram of material almost down to absolute zero, were they able to see anything exciting or interesting?

submitted by /u/CypressBreeze
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When I touch either very hot or very cold, I instantly recognize it is an extreme temperature, but sometimes it takes me a moment to realize which of the two it is... Why is that?

Posted: 03 Jun 2016 06:14 AM PDT

I hope this isn't a silly question and I hope this phenomenon isn't particular to me. I actually just asked a friend who mentioned how he poorly microwave-defrosted a chicken, and drew back his hand thinking he'd been burnt before realizing it was still partially frozen and he'd touched ice.

It's like the brain recognizes there is a big temperature difference between my skin and the surface, before it determines which is the hotter and which is the colder.

I know a little physics. I understand temperature in terms of average kinetic energy of molecules (though I guess solids might be different). I had it explained to me once that burns hurt because of energy transfer. But hot and cold seem objectively very different. Is there a crude part of the sensory system that recognizes temperature difference first? If so, how does the brain come to realize the sensation was in fact cold rather than hot? That doesn't seem to be a conscious judgment.

submitted by /u/Odds-Bodkins
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If the earth is protected from radiation and stuff by a magnetic field, why can't it be used on spacecraft?

Posted: 01 Jun 2016 07:36 PM PDT

Is it just the sheer magnitude and strength of earth's that protects it? Is that something that we can't replicate on a small enough scale to protect a small or large ship?

submitted by /u/AstrasAbove
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How can a permanent magnet do work on an object?

Posted: 02 Jun 2016 09:38 PM PDT

If you place two permanent magnets next to each other (with opposite poles facing each other) they will attract each other. The two magnets will accelerate toward each other and gain kinetic energy. Now I know that a charge in a magnetic field does not have work done on it as the force is perpendicular to the displacement (W=F*d where * is a dot product). In the case of the two permanent magnets it seems like the force is in the direction of the velocity. The force cannot be perpendicular as it makes no physical sense. So I assume that one magnet is doing work on the other and visa versa. How is this possible? Where is the energy coming from and how is this consistent with the first law of thermodynamics? I am assuming that some energy is needed to align the e- in the magnet. If that PE is used than wouldn't the magnet be discharged every time it "does work" on something?

submitted by /u/SpacePepper
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Why doesn't the greenhouse effect deflect energy from the sun before it hits the earth?

Posted: 02 Jun 2016 07:51 PM PDT

I have been recently looking into the greenhouse effect out of curiosity, and one thing that I have found is that the greenhouse effect warms the earth as when energy from the sun hits the earth, most of it is absorbed, and the rest is reflected back into space. The energy reflected back into space, however, first goes through the atmosphere, and some energy is reflected back into the Earth.


My question is that should some of the energy from the sun be reflected back into space, and because there is more energy coming from the sun that reflecting off the earth, why doesn't the earth become cooled from this effect?

submitted by /u/I-Am-Gaben-AMA
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Does transparent material like glass affects wifi as much as non transparent wall?

Posted: 03 Jun 2016 04:52 AM PDT

Could the greenhouse effect change the colour of the sky?

Posted: 02 Jun 2016 08:23 AM PDT

A clear daytime sky is blue because molecules in the atmosphere (Nitrogen, Oxygen, Argon) scatter blue light from the sun more than they scatter other types of light.

So if enough greenhouse gases (Water Vapor, CO2, CH4, etc.) were released into the atmosphere then could they change the colour of the sky?

submitted by /u/says_
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Is the maximum velocity of every atom the same (i.e. is the maximum velocity of an iron atom the same as the maximum velocity of a plutonium atom?)?

Posted: 02 Jun 2016 03:46 PM PDT

Why don't planes use single blade propellers with a counterweight?

Posted: 02 Jun 2016 02:47 PM PDT

A two blade design creates more drag comparatively as one blade must travel through the wake of the other, so wouldn't the weight of the counterweight be overcompensated by the increased efficiency?

submitted by /u/ilkikuinthadik
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Why does "1+4+7" takes us longer to answer than "7+4+1"?

Posted: 03 Jun 2016 04:22 AM PDT

Or any questions with the smaller number first. It might be me that counts slower that way.

submitted by /u/CrossSlashEx
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Could someone please explain how sunscreen works to me?

Posted: 03 Jun 2016 04:19 AM PDT

If I search on the internet, it says that a tan comes from UV-A and UV-B rays. Sunscreen is said to block UV-A and UV-B rays. How could a tan possibly build up at the same speed?

Also, is the risk of skin cancer equally as high with the same 'tan-level'?

submitted by /u/MrMcSloppyDoors
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Are there other ways of representing position than coordinates?

Posted: 03 Jun 2016 04:19 AM PDT

I saw a comment stating that a sufficiently large chessboard could describe the universe, and thought "Well, what about infinitely divisible things like distances?"

Later I figured it could probably be done accurately by using fractions, but I still wonder if there's a better - or even different at all - way of representing position than x y z.

submitted by /u/AxelPaxel
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What is the acceleration of light?

Posted: 02 Jun 2016 03:22 PM PDT

If I turn on a light source, how long does a photon take to accelerate to 3.0 x 108 m/s? Or rather, what is a photon's acceleration?

submitted by /u/JalarianDeAndre
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"Island of stability" elements: are they real?

Posted: 02 Jun 2016 02:20 PM PDT

Are these real things, or is it wishful thinking by the science-fiction crowd? If they're a real theory, is there any evidence for or against them?

submitted by /u/RandomUser1914
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If Bioquark was cleared to try and revive dead brains, why can't they revive a brain dead person's brain?

Posted: 03 Jun 2016 05:08 AM PDT

Charcoal and the conservation of energy; What happens?

Posted: 02 Jun 2016 04:48 PM PDT

During the process of creating charcoal, does the resulting charcoal have more or less energy than the original wood?

  • Heating wood could be increasing the stored energy?
  • "Semi burning" the wood could be using energy?

What happens?

submitted by /u/Vampanda
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(Why) does light have momentum?

Posted: 03 Jun 2016 03:02 AM PDT

I've heard from my physics teacher that light has momentum, as well as from things like explanations of solar sails. To my knowledge, p = mv. So, what gives?

submitted by /u/Simminz
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Does nuclear fusion happen within a neutron star? If not, why are they called stars?

Posted: 03 Jun 2016 03:02 AM PDT

I was just thinking that if a neutron star was entirely composed of neutrons, then there would be no way that nuclear fusion could occur, but then it wouldn't technically be a star. So if it is a star, how does fusion occur?

submitted by /u/coolamebe
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Does freezing meat in liquid nitrogen kill the same bacteria's that heating it does? Why cant you eat raw meat that has been frozen in liquid nitrogen and then reheated to room temperature?

Posted: 03 Jun 2016 03:01 AM PDT

Can SpaceX's rockets travel faster than the speed Earth orbits the Sun?

Posted: 02 Jun 2016 08:24 AM PDT

So I was reading the article about SpaceX planning on sending a rocket to Mars every ~26 months because that's when the Earth and Mars are closest to each other in their orbits.

So that got me thinking, if the rocket were to take off when the Earth isn't at it's closest point, will Earth overtake the rocket (assuming it's orbit takes it towards Mars at first)?

If my question is too confusing, how about this: if you leave earth, at what point is its gravity not strong enough to keep you with it, and Earth starts moving away from you (google says it orbits at 30km a sec!). And would this be a gradual movement or suddenly the Earth is moving away quickly? And is 30 km/sec faster than our spacecraft can travel? So if a spacecraft were to fall out of Earths gravity, it wouldn't be able to catch Earth and it would have to wait for it to orbit the Sun?

So relating to my original question about SpaceX, if the rocket took off at an inopportune point in Earths orbit relative to Mars, would the Earth "pass" the rocket or do our rockets go faster than 30 km/sec in space?

Sorry if it's too many questions or is confusing. All of a sudden I'm really interested in this.

Edit: I realize the phrase "fall out of Earth's gravity" will probably make some of you cringe, but I don't know how else to word it.

submitted by /u/MP412C17
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Are there any elements of pure chance in the laws of nature as we understand them?

Posted: 02 Jun 2016 01:51 PM PDT

My brother had this idea (which i guess is nearer to philosophy than science) that if there is no room for chance in the physical laws of the universe, then everything must be predestined.

I've taken a decent amount of science courses in my schooling (engineering undergrad) and never heard of a law or equation having any actual chance built in. I figured I'd ask some people much smarter than me if his premise makes sense.

submitted by /u/titanbubblebro
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Why do trees branch out as they do? Has anybody done it mathematically?

Posted: 03 Jun 2016 02:12 AM PDT

So, I was drinking coffee when my mind wandered off to a large rain tree nearby. I started to wonder, why do trees branch out as they do?

There has been some explanation here from botanists/biologists:https://www.reddit.com/r/askscience/comments/1518gx/what_determines_whenwhere_a_branch_will_grow_on_a/

But I wonder if it is just some kind of maximization/Lagrangrian problem. Has anybody tried this?

I was thinking, the tree probably was maximizing their canopy coverage (my noob phrase for area for sunlight absorption) while minimizing the branches to keep pressure pumping nutrients upward high. And I was thinking of the equations for this.

I guess to rephrase this, how do we find the most efficient count of branches in order to have the widest canopy area for possible sunlight absorption, given whatever constraint a tree has (gravity, capillary effect[?], etc)?

Has anybody thought of the same thing?

(Please don't bite me)

submitted by /u/chirdrd
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Thursday, June 2, 2016

AskScience AMA Series: We are earth scientists with the IRIS Consortium (www.iris.edu) and we study earthquakes and seismology. Ask us anything!

AskScience AMA Series: We are earth scientists with the IRIS Consortium (www.iris.edu) and we study earthquakes and seismology. Ask us anything!


AskScience AMA Series: We are earth scientists with the IRIS Consortium (www.iris.edu) and we study earthquakes and seismology. Ask us anything!

Posted: 02 Jun 2016 06:30 AM PDT

Hi Reddit! We are Danielle Sumy (seismologist) and Wendy Bohon (geologist).

From Dr. Sumy: I wanted to study earthquakes since I was 10 years old. I started off working in marine geology and geophysics, particularly studying fluid movement and small earthquake along mid-ocean ridges. I now study induced earthquakes and work on the Global Seismographic Network (GSN), and the Central and Eastern United States Seismic Network (CEUSN). I am currently a Project Associate with IRIS.

From Dr. Bohon: My research has focused on examining how the earth changes as the result of multiple earthquakes. I date dirt to find out when ancient earthquakes occurred (geochronology) and rocks to examine how mountains have changed through time (thermochronology). I have worked on fault related problems in the Himalayas (Ladakh), the Andes (Bolivia and Argentina) and in CA. I am an Informal Education Specialist with IRIS.

IRIS is a consortium of over 100 US universities dedicated to the operation of science facilities for the acquisition, management, and distribution of seismological data. IRIS programs contribute to scholarly research, education, earthquake hazard mitigation, and verification of the Comprehensive Nuclear-Test-Ban Treaty. IRIS operates the Global Seismographic Network (in collaboration with the USGS) as well as the Ocean Bottom Seismograph Instrument Pool and the EarthScope Transportable Array (which was named the most epic project by Popular Science!). IRIS also provides instrumentation for other geophysical experiments around the world, including in the polar regions, the Andes, Asia and the US.

You can find us on Facebook at https://www.facebook.com/IRIS-Education-and-Public-Outreach. We'll be available to start answering questions around 12 PM ET (16 UTC). Ask us anything!

submitted by /u/AskScienceModerator
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How does superposition of states and quantum entanglement work?

Posted: 02 Jun 2016 12:03 AM PDT

Hello,

I have recently looked into some QM but being the layman I am there are some few concepts I didn't quite grasp. First, what does the superposition of states in QM actually mean? Can multiple, mutually exclusive states exist at once? Or is it just a way of representing the unknown? For example, if we throw a coin and hide its result with our hand, would this describe a similar situation where we would say the coin's face pointing up is heads and tails at the same time until we observe the result? Wouldn't we be able to predict the value of the parameters of a quantum system by knowing its previous values, just like we would be able to predict the coin toss by knowing its velocity and direction of the throw? From what I understood, it is not the same situation because the result of the coin flip is already determined, whether we observe it or not. In QM, the states are actually undetermined until observed, and only then the parameters will take a definite state. However, I'm not sure how this all works out. If the present doesn't define the future, then what does? How does the quantum system decide which values it is going to take when observed? In which precise manner does the observation of a quantum system determines its states? I read that the quantum system "collapses" into definite states when observed, but what does that mean?

As for quantum entanglement, I don't understand why is it "spooky" for physicists. From what I understood of what I read, two electrons are produced from a single system, and each of them must have the opposite spin from the other according to the law of conservation of momentum. Now, that pair of electrons seems to communicate instantly, because whatever the distance separating the electrons is, when the spin of one electron is measured, the other electron instantly gets the opposite spin. This contradicts special relativity. However, what I don't get is why do physicists think the spins are determined only when they are measured in this particular case? Why is it impossible for the spins to have been simply determined at the moment of the entanglement of the pair of electrons? One electron has its spin up and the other down right from the start, and that way, information does not travel faster than light. Obviously I'm missing something and my view of this phenomenon is completely wrong. I would like to know why though, and of course would like to know what is the explanation given by physicists then, one that does not contradict special relativity.

Thank you all for helping a newb like me.

submitted by /u/PM_ME_NUNUS_DICK
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Does fracking actually disrupt the water table?

Posted: 01 Jun 2016 09:39 PM PDT

Hello /r/askscience! My first question, lets see how it goes. Fracking is all over the news regarding polluted groundwater. How is it that when fracking these wells, it creates a disturbance in the water table? According to the Energy Information Association, the average depth of a well is around 5,500ft (I eyeballed the average depth of wells in the 2008 column, link below) where I've never heard of a water well with much more than a 200 ft depth. I know there are instances where a water well goes deeper, but that seems to me like a very large distance for the fracking pressure to interact.

Energy Information Association Link: https://www.eia.gov/dnav/pet/pet_crd_welldep_s1_a.htm

I'm not looking for a debate or to be controversial, just wondering how much stock I can put into the news.

submitted by /u/IdahoIsMyName
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According to video (linked inside post) the corpus callosum acts as a "bus" (in computer science terminology). Are there other such well-defined "buses" in the brain?

Posted: 01 Jun 2016 03:58 PM PDT

Video quoted in the topic:

https://www.youtube.com/watch?v=wfYbgdo8e-8

(Not sure on the flair for this post. Decided Biology over Computing/Engineering)

submitted by /u/SubnetDelta
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How does a diaphragm affect depth of field for an imaging device?

Posted: 01 Jun 2016 02:24 PM PDT

How does a diaphragm affect the depth of field for an imaging device?

I understand that as the diameter of the diaphragm decreases, the depth of field increases. My question is two fold:

  1. Am I understanding this right? As the diameter decreases, objects farther away appear sharper?

  2. What causes this effect? How can the blur of an object farther away be decreased by simply "blocking" incoming light (decreasing diaphragm diameter). Does the lens have to change any of its attributes (position, focal length) along with the change in diaphragm to achieve this?

If you have any images explaining this effect, I would greatly appreciate it.

submitted by /u/Kevat
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After sunlight exposure in vacuum, does the ISS hull become charged due to the Photoelectric Effect? If so, does this create any technical problems?

Posted: 01 Jun 2016 06:21 AM PDT

Does the depletion of underground aquifers by humans contribute to global warming?

Posted: 01 Jun 2016 02:30 PM PDT

Water vapor is known to be a powerful greenhouse gas. I've heard crazy climate change deniers say "if you spit, the water vapor released warms the planet more than your carbon footprint that day." This might be half true, but the water in my body is already part of the existing water cycle. But if we take water out of the ground faster than it's replinished, are we adding more water vapor to the water cycle and hence warming the planet?

submitted by /u/ienjoyapples
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Is there such a thing as Cosmic Ray panel research?

Posted: 01 Jun 2016 11:31 AM PDT

The sun is (for us human) an infinite source of energy. However this source is only available during day time, depends on meteorological and atmospherical conditions, moves during the day, and solar panel depends on the break-down of a complicated particle (photon) of which the theoretical efficiency output is 35% or more if heat is converted and photon as particle-wave was theoretically to be converted.

But there's other kinds of particles that Earth is being showered with constantly, independently of day time or movement, which are comics rays, of with the secondary output (or shower) are a series of particles some of which electromagnetic radiation and different hadrons like muons that decay into an electron (and two neutrino).

So rather than only focusing on Solar Panels depending on variable contextual conditions, wouldn't it be possible to research into different kind of panel taking advantages of these different particles being bombarded on Earth constantly?

Thx

submitted by /u/EdgarSpayce
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What would happen if a large chunk of the earth were to disappear?

Posted: 01 Jun 2016 01:30 PM PDT

If some kind of disaster were to occur where a large chunk of the earth disappeared kind of like the earth from Adventure time. http://i.imgur.com/sKO312g.png Would there be any dire consequences to human life, would there be any damages to man-made structures. Would humans still be able to live on this planet or would we have to relocate?

submitted by /u/RohaniBoy
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Which phyciatriac disorders can be identified via an EEG?

Posted: 01 Jun 2016 10:32 PM PDT

And another question, is there any of the above disorders resemble similarity in EEG reading to ADHD?

submitted by /u/BlackFeeder
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The closest star system, Alpha Centauri is ~4.37 light years away from earth. How long would it take to get there relatively? (hear me out)

Posted: 01 Jun 2016 09:17 PM PDT

If time dilation exists and gets more extreme as the speed of light is approached, does that mean if a ship travelling at 95% the speed of light would experience this dilation and it would take just over 4.37 years for them to reach the system in relation to observers on earth? and then would the observers residing inside the ship travelling at these speeds feel like it takes far less time?

submitted by /u/hazmic
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If I'm finding the possible combinations of a password with 6 characters with case sensitive letters and one of these has to be a number, how do I find the possible combinations?

Posted: 01 Jun 2016 09:17 PM PDT

Is the answer to basically just do the permutation? 626. Since 52 letters (26 upper + 26 lowercase) and 10 total numbers. Or do I have to do 6C1 x (36)5 x (10)1 ? or is it 626 - (526 -106 )? all of these give me different answers and I am unsure which one is right.

submitted by /u/Emilio8744
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How do Helicopters sustain lift while also lowering the pitch in an autorotation?

Posted: 01 Jun 2016 10:24 AM PDT

Basically as the title says, but how is it possible for the upwards flow of air to turn the rotors but then also have the rotors create lift at the same time. Wouldn't you need negative pitch for an autorotation? Thanks!

submitted by /u/Flateye
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How does a directional AC meter know which direction power is transmitted?

Posted: 01 Jun 2016 09:10 AM PDT

How does a directional AC meter know which direction power is transmitted? Voltage and current are always flowing back and forth. What element does the meter look at to determine power flow direction?

submitted by /u/ARAR1
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Why does the surface area of a revolved solid include the arc length formula? Why not just integrate the circumference formula?

Posted: 01 Jun 2016 09:53 AM PDT

Why don't deBrogile wavelengths get infinitely large as an object's speed approaches zero?

Posted: 01 Jun 2016 07:45 AM PDT

I'm learning about this in my physics class and we learned tht you can calculate it with the equation lambda=h/mv and just looking at that as something's speed (v) approaches 0 (which happens all the time as things slow down to a zero velocity) it's wavelength should get arbitrarily large. I've asked a couple different teachers and no one has given me an answer.

submitted by /u/Josher1959
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If one were to attach two gyroscopes to each other, could gyroscopic precession be negated?

Posted: 01 Jun 2016 09:18 AM PDT

Take this example image which shows two gyroscopes attached to each other and spinning in opposite directions. Because the direction of the gyroscopic precession of one gyroscope is always countered by the other, how would such a device behave? Would the device still resist rotation? Would it be able to lay at a 45 degree angle and just sit there?

submitted by /u/dicvt
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How does a spacecraft gravity assist or slingshot work?

Posted: 01 Jun 2016 11:58 AM PDT

What determines the tempratures at which substances change state?

Posted: 01 Jun 2016 08:05 AM PDT

So basically I was thinking about how they use liquid nitrogen to cool things. I had assumed they did this is because it's a good heat insulator or something, but then I realised that doesn't make sense since you literally use is to cool things. Then I realised it must be because it stays liquid at that temperature. I then heard about people using liquid helium for even more extreme cooling. Am I correct in thinking that the lighter an element is, the lower its freezing point? However, most stuff is made from carbon right? Is that solid because it's bonded?

Also I'm confused about boiling points, water evaporates at room temperature right? So what even is the boiling point, the temperature at which you start seeing bubbles? Is that even useful information?

It's worth noting that my chemistry knowledge is horrendous, I'm just trying to imagine what this stuff physically corresponds to.

submitted by /u/larok00
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How does Science determine our prehistoric diets, what were they like, and how did they come to be? Specifically in relation to meat. 'Biology'

Posted: 01 Jun 2016 02:50 PM PDT

I was discussing the topic with a friend and we came at odds over the subject and the importance of meat in the diets of our prehistoric ancestors. I'm making this thread to try to get Well Sourced answers on the subject of prehistoric diet, meat eating. It's importance, prevelance and it's role in those diets.

It would also be appreciated if you explained how scientists came to these conclusions in the first place.

I understand that this is quite an extensive question, but I think it's both an intensely interesting and important one.

Thank you in advance for the hard work!

submitted by /u/anon2016b
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What do single-step and multi-step growth curves tell you about viral growth?

Posted: 01 Jun 2016 10:58 AM PDT

Obviously, I know that they each tell you aspects of viral replication rates. I'm confused as to why you would use one vs. the other. I know that you use a high MOI for a single step which results in a "synchronized" infection vs a low MOI for a multi-step infection.

submitted by /u/Grav0
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Wednesday, June 1, 2016

AskScience AMA Series: I'm /u/themeaningofhaste and I'm helping to build a galactic-scale gravitational wave detector. Ask Me Anything!

AskScience AMA Series: I'm /u/themeaningofhaste and I'm helping to build a galactic-scale gravitational wave detector. Ask Me Anything!


AskScience AMA Series: I'm /u/themeaningofhaste and I'm helping to build a galactic-scale gravitational wave detector. Ask Me Anything!

Posted: 01 Jun 2016 05:00 AM PDT

Hi everyone!

I'm a pre-postdoctoral researcher working as a member of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration, whose goal is to detect low-frequency gravitational waves. Earlier this year, LIGO announced the detection of gravitational waves but they were looking at gravitational waves from two stellar mass black holes merging. NANOGrav is attempting to look for gravitational waves primarily coming from supermassive black holes at the centers of merging galaxies. Just like there are many different kinds of electromagnetic telescopes (optical, radio, X-ray, etc.) to observe different kinds of phenomena in the Universe, astronomers are looking to build a number of different gravitational wave observatories across different frequencies for the same reason and NANOGrav is helping to fill the low-frequency window.

My work has involved understanding all of the processes that limit the precise and accurate timing of pulsars, the clocks we use to measure the stretching and compressing of spacetime caused by gravitational waves. Pulsars aren't perfect clocks, pulses become distorted in the interstellar medium, telescopes can't make perfect measurements, and then somewhere under all of that exist the gravitational wave signatures in our data. NANOGrav uses the two current largest radio telescopes in the world, the Arecibo Observatory in Puerto Rico and the Green Bank Telescope in West Virginia, to make really precise measurements of over 50 of the highest-precision pulsars known distributed throughout the galaxy.

Besides that, in my spare time I help to organize AMAs for a group called AskScience on a website called reddit :) I'll be around to start answering questions around 12 PM ET (16 UTC). Ask me anything!

submitted by /u/AskScienceModerator
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What happens to a molecule which has an element which is part of its construction reach its half life?

Posted: 31 May 2016 05:46 PM PDT

For example, Carbon-14 has a half life of about 5730 years per Wikipedia, and since Carbon is a major building block of life C14 has found its way into all organic life on Earth in the same concentrations as we find in our atmosphere. So what happens, for example, when one of these C14 elements reaches its half life in a molecule of an amino acid within our own DNA?

submitted by /u/Atriven
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Would it be possible to create a liquid or gas comprised solely or mostly of photons?

Posted: 31 May 2016 07:48 PM PDT

I was watching a sci-fi movie with my oldest son tonight and one of the characters (mad scientist type) said that he had succeeded in creating a fluid solely from light.

My immediate reaction was to blow it off as science fiction hand waving to solve a problem but, after an hour or so, I started working it over mentally. Since photons are elementary particles, would it be possible to condense them into a fluid state as a liquid/gas? Something that would take the shape of a container (assuming that you had already devised a suitable container)?

submitted by /u/dubbya
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Do cannabinoid receptors degrade with cannabis use?

Posted: 31 May 2016 10:41 AM PDT

Just learned about how cocaine use can lead to receptor degredation due to a decrease in neurotransmitter uptake. How does THC act within the body? Does it produce a lessened effect , as in it takes longer to gain a tolerance, or does it do something completely different? Pls, I'm a grade 12 noob.

submitted by /u/Kisses_Bum
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What is different neurologically between sleep and a coma?

Posted: 31 May 2016 04:05 PM PDT

I was taught that damage to the RAS causes comas. Is this the only cause? Do coma patients dream? Do they go through brain wave cycles similar to a sleeping human?

submitted by /u/corbincox72
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Why does friction create heat?

Posted: 31 May 2016 04:41 PM PDT

Friction is the result of microscopic ridges on an object's surface and acting against frictional force generates heat. But if you were a giant, trees would be microscopic, meaning that microscopic is subjective and,thus, the size of the ridges isn't what is creating the heat. So what's going on when I rub my hands together.

submitted by /u/AnalyicalRiguy
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Can mountains prevent earthquakes?

Posted: 01 Jun 2016 01:41 AM PDT

Islam claims that mountains help prevent earthquakes. Is there any scientific evidence to back this claim? Do mountains have any effects on earthquakes (increase or decrease)?

submitted by /u/fromsialkot
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What would a distance vs time graph look like for a rocket accelerating from rest to relativistic speeds?

Posted: 31 May 2016 06:05 PM PDT

Would time dilation and length contraction cancel out and result in a straight line, or produce a weird sigmoidal looking curve?

submitted by /u/traplordalz
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Does the proximity of Mars to Earth affect the throughput available to the landers and orbiting probes?

Posted: 31 May 2016 11:53 PM PDT

Mars is very close to Earth at the moment, and if my envelope math is correct, about 4 light-minutes away. Does this proximity allow NASA to receive more data than they would otherwise? Or is the difference between closest/furthest not significant compared to the amount of data that needs to be transmitted?

submitted by /u/Baeocystin
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Why are bubbles always spherical when blown?

Posted: 31 May 2016 04:59 PM PDT

Whenever bubbles are blown, they appear to always be in a spherical shape of different sizes. Why not cubes or other shapes?

submitted by /u/JMurray1121
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Is the success of the Lebesgue integral related to the vertical line test?

Posted: 31 May 2016 08:20 PM PDT

At risk of oversimplifying, Riemann integration uses vertical rectangles (partitioning the domain) to approximate area, whereas Lebesgue integration uses horizontal rectangles (partitioning the range). It seems odd to me that such a difference would have any effect at all, and yet Lebesgue integration is much more powerful. As far as I know, the only inherent asymmetry in the domain vs. range of a function comes from the vertical line test. Are these two things related?

submitted by /u/seltivo
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Why is there only one species of Human?

Posted: 31 May 2016 11:11 PM PDT

According to Wikipedia, humans exited Africa roughly 100,000 years ago, so we've been spread out across continents for quite a long time. If there was so much geographic separation between populations for such a long time, why didn't different species (or subspecies) of humans develop? Why are we the only ones left?

It just seems crazy that I'm the same species as every other person on earth, even though we might share a common ancestor tens of thousands of years ago. If there had been a bottleneck, where only a small population of humans survived and then populated the world, then I could understand it more. But it seems incredible that there's so many types of tiger, lion, squirrel, etc. but only one intelligent primate.

I know there were other (sub)species such as homo erectus or neanderthals. But why did they all die out? Wasn't there enough room for pockets of them to survive somewhere? Why hasn't homo sapiens similarly fragmented into subspecies since then?

submitted by /u/transient279
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What's the difference between hard and brittle?

Posted: 31 May 2016 04:30 PM PDT

I mean from the molecular (or bond?) standpoint. Why is it that something can be very hard and yet brittle? It seems like both properties are essentially a strong bond between molecules.

submitted by /u/mykevelli
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Is absolute silence possible in non-deaf humans?

Posted: 31 May 2016 10:21 PM PDT

Is or could there be a time where a person's functioning ears are actually picking up no sounds whatsoever, not even the tiniest one?

submitted by /u/hahaijoinedreddit
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Do split brain patients lose the ability to add tone/emotion to their speech?

Posted: 31 May 2016 09:58 AM PDT

Based on my understanding, the speech centers (Broca's and Wernicke's) produce speech on the dominant side of the brain and add tone and emotion on the non-dominant side. CGP grey's video on the front page implied only the left brain (which he assumed is dominant) is involved in speech in split-brain patients, therefore you should lose emotional speech in split-brain patients, right? Or is it possible you still have emotion added, but it reflects the emotional state of the non-dominant brain and so may contradict the message being sent by the dominant brain?

Thank you for any answers!

EDIT: I was mistaken by using the word emotion. Here is a chart for my medical school textbook referring to a few Brodmann areas and their function.

http://imgur.com/cwNxrYz

I am asking if Brodmann areas 44, 45, and 22 on the non-dominant side appear to stop functioning in split-brain patients or if they function in a manner that causes the speaker to have a tone that does not match his/her intended tone because of the lack of communication between the two hemispheres of the brain. The left brain communicates its thoughts through the usage of words and grammar while the right brain communicates through tone, causing potentially conflicting messages being sent. I'm sorry that I asked it in a weird way earlier and I hope that clears it up.

submitted by /u/Stingray1993
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Is there a difference in the layout of veins between two people?

Posted: 31 May 2016 10:14 AM PDT

Would it be possible to quantum entangle two different particles, like a neutrino and an electron?

Posted: 31 May 2016 02:51 PM PDT

Is Hawking radiation breaking the law of conservation of energy?

Posted: 31 May 2016 01:57 PM PDT

Is the law not broken because one virtual particle (becoming real) enters the universe and the other enters the black hole (On a black holes holographic surface or otherwise).

submitted by /u/Leguro
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Mouse models for disease?

Posted: 01 Jun 2016 01:13 AM PDT

How do they test diseases, specifically cognitive diseases, in mice, like dementia or Alzheimer's? Or really any disease for that matter. I can't seem to find an answer on Google, however, given my ignorance I may be searching the wrong phrase. Any help would be great. My background is I am certified and work as a paramedic. Thanks.

submitted by /u/Plays_in_traffic
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Why do some chemicals, other than water, exhibit an anomalous expansion?

Posted: 31 May 2016 01:16 PM PDT

I know that this is the case, for instance, with Bismuth. But if this happens with water due to its Hydrogen/Oxygen attraction, then how does it work for metals?

submitted by /u/LucasTyph
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If you're stuck in a room, can you prove you're on a planet?

Posted: 31 May 2016 09:00 AM PDT

If you were stuck in a room and there was a chance you were NOT on a planet (but instead somewhere that someone was trying to convince you WAS a planet), to what extent could you test to find out? Would you need any special tools?

Context for why I'm asking: I used to joke with friends that the Earth was secretly flat, just for laughs and to hear what they had to say about it. One then-friend wouldn't have fun with it at all, and, while being adamant that we definitely were on a planet, made the claim that he could prove it right then and there if he wanted to. He was academically able but also quite full of himself, so I've often wondered if he was right or just being dismissive.

I guess another version of this question would be:

"Could you make a flat structure in space that the people on it couldn't easily differentiate from a planet?"

submitted by /u/HareTrinity
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Can a conductor composed of muonic atoms exist due to relativistic effects?

Posted: 31 May 2016 01:26 PM PDT

I understand that muonic atoms can exist but that they decay at a rate of a few microseconds. Would the decay rate of these atoms decrease due to relativistic effects in a strong gravitational field? Ex. A planet which is composed of muonic elements orbiting a blackhole.

Additionally, could such matter be used a conductor and what would be the characteristics of a "muonicity"?

submitted by /u/R3ptar1337
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