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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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Tuesday, May 31, 2016

As the human body goes from being an infant to an adult, are there any organs or body parts that become smaller instead of larger?

As the human body goes from being an infant to an adult, are there any organs or body parts that become smaller instead of larger?


As the human body goes from being an infant to an adult, are there any organs or body parts that become smaller instead of larger?

Posted: 30 May 2016 11:31 AM PDT

How do we know the chemical composition of the Earth's core?

Posted: 30 May 2016 02:01 PM PDT

I understand that we know the Earth's core to be mostly Iron and Nickel, but how do we know this is the case?

submitted by /u/superhelical
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Why is Cherenkov radiation blue?

Posted: 30 May 2016 08:36 AM PDT

How would a person standing on the North Pole feel the effects of the earth's rotation?

Posted: 31 May 2016 06:54 AM PDT

Can kinetic energy be directly converted to light?

Posted: 30 May 2016 09:24 AM PDT

Most forms of energy can be directly transformed into one another, like charging batteries, burning wood, wind turbines etc.

However, I dont know of any example where light gets created directly from kinetic energy, and I had some science teachers say that its impossible. Is this true?

submitted by /u/Jannik2099
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How do we calculate rates of change mathematically knowing what we do about quantum mechanics?

Posted: 30 May 2016 04:05 PM PDT

The obvious example is current. We know charge is a discrete value, so we can't use basic calculus to find the rate of change of charge as the derivative which, as I know it, can only be done on a continuous function.

submitted by /u/Walsur
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Why is it supposed to be worse to get your tonsils out when you are older?

Posted: 30 May 2016 10:17 PM PDT

I'm having my tonsils out on Friday and I'm told that the recovery will suck much more than if I had gotten them out as a child(I'm 24). Like, I might not be able to speak for 2 weeks and the pain is supposed to be horrible. I hear it can even permanently change my voice. Why is this?

submitted by /u/Awww_Yee
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What's the strongest biomaterial made by a living thing or in a living thing?

Posted: 30 May 2016 06:16 PM PDT

Sensory/cognitive functions of a housefly: How do they navigate, operate and perceive their surroundings?

Posted: 30 May 2016 08:46 PM PDT

I am Curious of the current scientific consensus on this, since I'm convinced they don't use their eyes for threat recognition.

submitted by /u/weird_piano
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What happened to lemurs/Madagascar during the last ice age?

Posted: 30 May 2016 06:26 AM PDT

My kids were watching a show about lemurs, which led to us talking about lemur evolution (how/when did they get there), which led to a question about how did lemurs deal during the last ice age. Fun fact: when you google "Ice Age Madagascar" you get a lot of things about animated movies and little about lemur evolution. I'm hoping one of you can help us out. Thanks!

submitted by /u/Cardano
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Are Black Hole forming Supernovae less energetic than Neutron Star forming Supernovae?

Posted: 30 May 2016 12:04 PM PDT

I've been wondering about this for a while but haven't really had anyone to ask. Nothing suggests this is true, but knowing some basics about how supernovae occur, I can't figure out why it wouldn't be.

From what I understand, Supernovae occur when Fusion sharply cuts off due to the forming of Iron-56 which can't fuse and release energy, therefore the radiation pressure cuts off so the star's own gravity can finally cause the star to collapse. The actual supernova itself is a combination of two factors. Firstly, when the electrons are forced into the protons, a vast number of high energy neutrinos are produced. These are absorbed by the incoming matter due to the sheer number of them, and this forces the collapsing star back on itself.

That was just a precursor to see if my current knowledge is correct. This point is what leads to my question. The second factor that causes a star to get blown outwards is the contact of the incoming shockwave with the incompressable core, so the shockwave has no choice but to rebound outwards. In the case of a neutron star forming, this is true so it seems to stand true. However when a black hole forms the force is such that even the core is not incompressable and can in fact be compressed infinitely to a singularity as not even neutron degeneracy pressure can withstand it. As such, the shockwave will simply be absorbed into the singularity as the black hole forms rather than rebound, therefore less energy is reflected back onto the collapsing mass so the supernova is less energetic.

Why is this not the case?

Also, as an aside, is Neutron Degeneracy pressure which prevents every supernova-undergoing star from collapsing into a full black hole rather than a neutron star the same as the strong force?

submitted by /u/TRPAlternative
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How does our immune system "know" not to attack our gut flora?

Posted: 30 May 2016 05:38 PM PDT

What mechanism allows our gut flora to exist without being attacked by our immune system? Especially bacteria such as E. coli that are potentially pathogenic?

submitted by /u/internetboyfriend666
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Eye-glasses prescriptions, especially the astigmatism, can change abruptly upon giving birth. What is going on here?

Posted: 30 May 2016 11:37 AM PDT

There's some amount of evidence that women's eye prescriptions can change abruptly upon giving birth. What is going on here? What CAN be going on here? Is the eye deforming itself differently? Is the eye being deformed differently than before the pregnancy, presumably by some change in the "posture" of the extra-ocular muscles (this would be a change in the resting tension perhaps)? Is there a hormonal change that changes the mechanical properties of the sclera / cornea allowing for the usual mechanical stresses to result in different mechanical strains? Does the eye undergo mechanical plastic deformation under the mechanical stress imparted by the extra-ocular muscles during pushing out a baby?

Or do the optometrists just measure post-partum women's eyes differently than they do before the woman gives birth?

Most of these alternative seem silly to me. Maybe I'm missing some possibilities. Is there anything known about this?

submitted by /u/justPassingThroo57
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Why is ductility often listed as a separate property of a material from malleability?

Posted: 30 May 2016 09:22 AM PDT

To my understanding, malleability is a material's ability to be shaped (as opposed to being brittle and failing) and ductility is a material's ability to be drawn into wire. Is drawing into wire not simply a certain way to shape something? Are there materials that are malleable, but not ductile? Are there materials that are ductile, but not malleable? If these materials exist, why do they behave the way they do?

submitted by /u/DiamondIceNS
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How can photolithography print things a few nanometers across when the wavelength of light used it much larger than that?

Posted: 30 May 2016 06:26 PM PDT

My understanding is that modern electronics often have transistors printed on the ~10nm scale, but the UV light used in the photolithography step is around 300nm. I thought the diffraction limit is around wavelength/2. So how are such small transistors printed without using x-ray?

submitted by /u/NeuroBill
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I know that time dilation occurs when one object is moved relative to another, but if there is no frame of reference in space, how do you determine which object will be older?

Posted: 30 May 2016 01:08 PM PDT

Title

submitted by /u/COWRATT
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What role does meiosis play in cleistogamic species?

Posted: 30 May 2016 10:44 PM PDT

Cleistogamic species being flower species that do not open and self pollinate. Meiosis mainly reorganizes genetic material to introduce new genetic combinations, so why would a species that can't have 'new genetic material' still undergo meiosis? Just to reduce chromosome numbers?

submitted by /u/Allister24
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Can Perpectual Motion work? (In this cheaty way)

Posted: 31 May 2016 03:56 AM PDT

I'm 15, and I'm not super science guy(yet), and I've been thinking about perpetual motion. It's fake. It's impossible. Right?

I've never owned myself a 'perpetual motion' contraption, so I had never have the chance to make long observations of it. Even the internet doesn't have observations of it. Mostly all of it just gives definition,history,types,impossibility, etc. So, 'perpetual motion' is a continuous moving object right? Such as the over balanced wheel(I'm going to focus more on this type).

How this 'perpetual motion' works:

  • the wheel will spin when very little energy is applied
  • it spins for a long time(ex: 10 minutes)
  • the machine stops*

But does it spins for another 10 minutes if another little energy is applied?

If so, ['perpetual motion'] + [energy(only when the machine stops)] = Actual Perpetual motion?

  • Also, if perpetual motion is fake, what is the right name for the commonly called perpetual motion machines?
submitted by /u/FarEast_Frez
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Why does ink stay on a page?

Posted: 30 May 2016 06:23 PM PDT

Does a moving medium (e.g. glass) also move light that is passing through it?

Posted: 30 May 2016 08:59 AM PDT

If light were passing through a transparent material and that material were moved (at a speed less than the speed of light) in a different (let's say perpendicular) direction from that of the light, would the light also be moved in the direction that the material moves or would it continue along its original path undisturbed the movement of the material that it is passing through?

In other words, is light like a goldfish that changes position when its fish bowl is moved, or is its path completely independent of any movement of its medium? I understand that light does not need a medium to move through (there is no "ether" in space that transmits the wave... perhaps the answer is in this fact), but I also understand that the velocity of light can be altered when it changes mediums and thus light can be influenced by the material it travels through.

submitted by /u/DiggerDave
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[Physics] Photoelectric effect and its uses?

Posted: 30 May 2016 10:50 PM PDT

I found this very intriguing, could someone please explain the photoelectric effect and its practical uses, if any?

submitted by /u/rick_dick_ulous
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Monday, May 30, 2016

Is it possible for a planets moon to share an atmosphere with the planet?

Is it possible for a planets moon to share an atmosphere with the planet?


Is it possible for a planets moon to share an atmosphere with the planet?

Posted: 29 May 2016 11:13 AM PDT

If a planet's atmosphere extends far enough, and one of the planets moons were close enough, could it share the planet's atmosphere?

submitted by /u/DeadMiner
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Sperm Whales have sockets in the top of their mouths for their bottom teeth, are these pre-formed or created by the teeth?

Posted: 29 May 2016 02:53 PM PDT

Sperm Whales have sockets in the top of their mouths for their teeth, are these pre-formed or created by the teeth? There are a lot of crooked teeth I'm curious if those just don't fit or if they make their own sockets somehow.

Example: http://i.imgur.com/5OqSMhj.jpg

submitted by /u/devlspawn
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What does the "moment" in moment of inertia mean?

Posted: 30 May 2016 05:39 AM PDT

Why are SpaceX landing at sea rather than land?

Posted: 29 May 2016 10:46 AM PDT

I'm thinking a land landing would help reduce the risks of weather/waves and the transport to and from the touchdown spot. Why have they chosen a barge rather than a large empty field?

I was thinking it would provide mobility in choosing a landing site, but this has never been a factor before in space travel, and they're launching the rocket from the same place regardless. Besides, there's no time to move the barge post launch I'm guessing.

submitted by /u/zombisponge
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How much power can an Optical Fiber carry?

Posted: 30 May 2016 04:53 AM PDT

For example if we wanted to transmit a laser beam or concentrated solar light how much power can we transmit before the optical fiber heats up and melts?

submitted by /u/HAL-42b
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Why do neutrinos oscillate but electrons don't?

Posted: 30 May 2016 12:41 AM PDT

Are there any interesting theories as to why neutrinos would oscillate but not electrons given that they're both leptons?

submitted by /u/Rickasaurus
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Is the solar wind significantly charged? Does this charge (if it exists) in any way affect spacecraft?

Posted: 30 May 2016 03:29 AM PDT

How does one determine the volume of water vapor per unit of atmosphere?

Posted: 29 May 2016 11:15 AM PDT

Does a single solar mass black hole exhibit the same gravity effects as the sun?

Posted: 29 May 2016 11:09 PM PDT

I imagine they are similar at the distance we are from our sun. But it also seems like if I got closer, at a certain point, things would be different. Where would that point be? For example, if I'm in a ship, when would I stop experiencing the gravitational effects of a regular star and start experiencing the unique gravitational effects of a black hole?

submitted by /u/_mizzar
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Is Dry Ice Hydrophobic?

Posted: 29 May 2016 08:42 PM PDT

It's exactly what the title suggests. Wouldn't it be considered hydrophobic because it never comes in contact with the water? looking at video of someone dumping it into water, it is clear there is a layer of gas surrounding the dry ice at all times keeping it from ever contacting the water. So, doesn't this mean it is hydrophobic.

submitted by /u/Lamshoo
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How is the rate of isostatic rebound calculated?

Posted: 30 May 2016 04:48 AM PDT

I'm reading a textbook for a university course I'm taking and it refers to isostatic rebound i.e. land mass that was once covered in ice sheets rising once the ice sheet retreats.

The concept is easy enough to understand, but the textbook then goes on to state "....depressed the Earth's surface, and even though they retreated around 11,500 years ago, the land is still rising due to a process known as isostatic rebound. Since the ice retreated, land in the north of the British Isles, which was covered by thick ice sheets, has gradually continued to rise, while that in the south, which had no ice cover, has been tilting down, causing a relative rise in sea level in this area at a rate of about 0.15 of a metre per century."

My question is how is this calculated so accurately?

submitted by /u/shanghaikid
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When you cast aluminum ingot it shrinks when cooled. Why does it happen in the middle of the casting?

Posted: 29 May 2016 07:52 PM PDT

I feel like this paper might explain it, but can someone EILI5?

submitted by /u/titleunknown
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How to assume material wear?

Posted: 30 May 2016 04:16 AM PDT

Hello! My question is - how to assume wear of the material over time?

I.e.1 - I have a pipe. In time pipe's walls can get thinner due to wear. But how to approximate rate of the wear process over the years? I.e.2 - I have a steel bowl or funnel. I pour granules or flings of a softer metal (let's take copper as example). What can happen to the funnel over time? In theory copper is much softer so it can't even make a scratch.

I have found scientific articles on wear with experimental data, but I suppose this is so case-specific, that I can't make any extrapolations or assumptions for other cases based on that. Or can I?

submitted by /u/lavencof
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Why do they say to avoid the sun between 10 and 3 (or 11 and 4 daylight savings time)? Shouldn't the hours be symmetric about noon, when the sun is at its peak?

Posted: 30 May 2016 06:41 AM PDT

How does an expanding universe not violate the "Conservation of ... laws"?

Posted: 30 May 2016 02:33 AM PDT

If a Planck unit is the smallest possible unit, how would this affect rotation? Would this affect your ability to aim at something an extremely long distance away?

Posted: 30 May 2016 04:36 AM PDT

You'll have to excuse my poor understanding of Physics, I've just been playing EVE Online and had a thought regarding planck lengths while I was aligning to a gate. If there is a limit to length in terms of smallest size, would this affect your ability to aim at something an extremely long distance away, due to rotation? For example, if you pointed a telescope at an object that was an extreme number of lightyears away, would you only be able to "snap" to a point eitherside of the object if it fell inbetween two plank lengths of rotation? Am I misunderstanding the way in which Planck lengths work?

submitted by /u/Kraynos
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How does melanin protect us?

Posted: 29 May 2016 11:28 AM PDT

Could you carbon date something from the future?

Posted: 30 May 2016 12:09 AM PDT

I was watching Terminator guys! And I started wondering whether you'd be able to date something from the future

submitted by /u/Pussay_patrol_
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Some Cameras in space appear to degrade quickly over time, why is this?

Posted: 29 May 2016 06:24 AM PDT

In videos such as: https://www.youtube.com/watch?v=JiV0V8t4DYU You can clearly see artifacts on the camera appearing over time, from dots to a large line of missing pixels. What causes this? Is it just stray radiation? Why does this not effect some other cameras?

submitted by /u/TheSirusKing
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How does a plant seed know which way is "up"?

Posted: 29 May 2016 03:07 PM PDT

I guess since they are buried deep in the ground with no sunlight or without any other way of knowing which way it should grow to get the surface.

submitted by /u/TehMau5
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When I twirl a rope at a high speed, where does that "swoosh" noise come from?

Posted: 29 May 2016 04:26 PM PDT

If the universe is 14 billion years old and the sun is 4.5 billion years old. Was the universe 9.5 billion years old when the sun was born?

Posted: 29 May 2016 05:26 PM PDT

Or is there some relativity factor that is missing?

submitted by /u/TheBeads
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Why does plaster of Paris heat up as it hardens?

Posted: 29 May 2016 06:31 PM PDT