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Sunday, April 17, 2016

Is the sun soft or hard?

Is the sun soft or hard?

Is the sun soft or hard?

Posted: 16 Apr 2016 06:45 AM PDT

To give an example; if I was flying a spaceship (let's assume it can withstand the extreme conditions), and I wanted to enter the sun, would the ship just sail through or would it crash on the surface?

submitted by /u/Jiji5
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Why are men who have had sex with other men not able to donate blood?

Posted: 17 Apr 2016 12:05 AM PDT

I believe it is against regulation at least in the US.

submitted by /u/thefangster7needsaid
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How did the scientists, in the dawn of chemistry as we know it, knew when they found a new element? How were they sure it wasn't just another compound?

Posted: 16 Apr 2016 07:55 PM PDT

Taking boron as an example: it was discovered in 1808. How did Gay-Lussac and the other scientists who discovered it knew it was a completely new element?

submitted by /u/Lichewitz
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Are earthquakes "connected"?

Posted: 16 Apr 2016 09:13 PM PDT

I've been noticing in the past couple of years that when a medium to large-scale earthquake happens in one part of the earth, another one follows within a week or two in another part of the earth. This makes me think that there is a connection between them... the most recent example being the 7-magnitude quake in Kyushuu, Japan and the 7.8 in Ecuador. If this is true, can someone explain?

submitted by /u/cooperCollins
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Does the discovery of gravitational waves falsify quantum mechanics?

Posted: 16 Apr 2016 09:18 PM PDT

What is the unit of measurement for gravitational waves?

Posted: 16 Apr 2016 02:44 PM PDT

Now that we have found einsteins gravitational waves; I am writing a bit of science fiction which is centered around space-fold/warp technology. I am curious, now that Einsteins gravitational waves have been proven; what is the unit of measurement by which they are measured? Also are these gravitational waves measurable in the electro-magnetic wave-length? I ask, because by this measure, wouldn't "warp" drives use wave-length to measure jumps?

submitted by /u/lordpoee
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Are the electrons within an atom entangled?

Posted: 16 Apr 2016 01:32 PM PDT

Because of Pauli's exclusion principle, two electrons within the same orbital cannot have the same spin, so, this means that by measuring the spin of one electron you automatically know the spin of the second electron. Are the electrons really entangled? Does the same math that is used to describe entanglement describe what's happening here?

submitted by /u/yeahbitchphysics
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Can you use quantum entanglement to get around Heisenberg's uncertainty principle?

Posted: 16 Apr 2016 12:13 PM PDT

Could you not measure the momentum of one entangled particle a and the position of the entangled particle b, then use the momentum of the entangled particle b as the momentum of entangled particle b?

submitted by /u/CitizenWoot
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Could enough rotational energy be imparted to a black hole to rip the singularity apart?

Posted: 16 Apr 2016 08:11 AM PDT

I was just thinking about centrifugal force and I was wondering if enough rotational energy could theoretically be added to a black hole to cause the singularity to be pulled apart and release the mass contained in the black hole.

Is it theoretically possible? If not, what would prevent that from happening?

submitted by /u/rebbsitor
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How strong a gravity could humans adapt to?

Posted: 16 Apr 2016 10:18 AM PDT

For a sustainable society everything else being equal what is the strongest gravity a human world can have? And what would a visit to Earth be like for the inhabitants of this hypothetical world?

submitted by /u/wickedsteve
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What exactly makes a bolide explode in the atmosphere?

Posted: 16 Apr 2016 12:02 PM PDT

Been looking around Wikipedia for an answer to this, but it doesn't explicitly say it so I'm still not sure. Does the bolide contain something in its body that's explosive? Is it just that if it's hot enough, it cracks like wood in a fire? Or is it something pressure-related?

EDIT: I scoured Wikipedia but forgot to do a basic Google search, which I did after I got the bot's message. So Today I Learned it's the air pressure that makes it shatter. Secondary question still applies though.

As a secondary question, Wikipedia's list of meteor air bursts page has a chart that says the (average, I'm assuming) kinetic energy yield during an air burst, for an asteroid 20m in diameter, is 230 kt of TNT equivalent--but the Chelyabinsk meteor, with the same diameter, released double that at 500 kt. What makes the explosion vary like this?

EDIT (same one as before): Also, on the meteorite thread from the FAQ, there was a question that got asked but I don't think got answered. Was it the air burst specifically that caused windows to shatter, or was it "just" the fact that it was making continuous sonic booms, strengthened by the fact that the meteor fell at an angle?

submitted by /u/AKAAkira
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What are some "presentable" nuclear or quantum physics subjects?

Posted: 17 Apr 2016 03:32 AM PDT

Hello,

We have to present a topic to the class in my Modern Physics class. It should be about nuclear physics or quantum physics, yet I am unable to find something interesting that we didn't already learn.

"You will be giving a 16 minute seminar, with a maximum of 2 minutes for additional questions, during class time in May- June. Your presentation will be based on a topic from nuclear physics, or from medical physics, or from quantum physics and will be approved by your teacher beforehand."

What are some interesting yet rather unknown topics that come to your mind?

Thanks.

submitted by /u/klankeser
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Is there any place in the universe, or could we make a place, where EM field doesn't exist ? Are we able to PURGE an EM-Field ?

Posted: 16 Apr 2016 11:47 AM PDT

Is there any difference between mass granted by the Higg's mechanism versus mass granted by the Strong force?

Posted: 16 Apr 2016 09:44 AM PDT

Forgive my terminology, but as I understand it, the Higg's field creates mass for elementary particles, but the vast majority of mass we see is a result of the strong force holding together bundles of quarks and nucleons. How is it that these 2 seemingly different mechanisms result in something that on our scale look like exactly the same thing? Does mass created by the strong force interact with the Higg's field? Does mass created by the Higg's field interact with the curvature of spacetime?

submitted by /u/Camelfoe
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Is a square or a triangle shaped "tower" able to hold a heavier load?

Posted: 16 Apr 2016 12:42 PM PDT

I have noticed that different cell towers (or similar type tower) are sometimes Triangular (3 support pillars) and some are square (4 support pillars). I got into a discussion with a friend as to what the difference was between the two were and if one design can hold more weight than the other. We each have theories on why one is better than the other, but can't find a definitive answer. So I guess my question is, which can hold a heavier load, a square base or a triangle shaped base?

Edit: To be a little more specific,assume they both have the same build cost and amount of material put into it.

submitted by /u/tannerdanger
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What factors determine the "voice" of a crowd in a stadium chanting a player's name?

Posted: 16 Apr 2016 06:59 PM PDT

I'm watching the Capitals VS Flyers game and the Caps goalie has done a great job tonight. In the final seconds, the crowd was cheering "HOLTBY! HOLTBY! HOLTBY!" and it occurred to me that it appeared to be a pretty deep voice.

So does the shape of the stadium/dome affect the tone and pitch of the voice, or is it just an average of all the voices?

submitted by /u/Tnargkiller
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When a helium balloon contracts from the cold, does it loose lift power?

Posted: 16 Apr 2016 06:58 PM PDT

We have been sending off gas filled balloons attached to helium balloons, and we noticed that the helium balloons contracted and seemed to deflate in the cold. Since this space isn't being replaced with any other gas, does the balloon loose any power?

submitted by /u/Zorac877
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Will an object greater mass hit the ground faster than lighter object if they're dropped in still air conditions (no wind etc) and are of the same shape and size?

Posted: 16 Apr 2016 04:28 PM PDT

E.g. Two exactly similar balls with absolutely same size and shape, volume and all other physical properties, except mass are dropped from, say, plane, but with no wind to affect them. Will the heavier ball reach the Earth a bit faster?

submitted by /u/teinekin
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What's the mechanism of pH indicators? Why do they change color?

Posted: 16 Apr 2016 05:31 PM PDT

I understand that the molecule changes because a hydrogen ion is removed or added, changing resonance structures, but I don't see how resonance changes how light interacts with the molecule.

From what I've seen, I've also noticed that more indicators are more red on the acid side, and more blue on the base side. I was wondering, is that just a coincidence or does it mean something?

submitted by /u/minecraftian48
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During El Niño years do the trade winds over southern Atlantic also weakens?

Posted: 16 Apr 2016 07:53 PM PDT

I know that during El niño years the southern Pacific trade winds weakens.

What about the southern Atlantic trade winds? Do they also weaken?

submitted by /u/fellinitheblackcat
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What are the physical/neural mechanisms for keeping track of time?

Posted: 16 Apr 2016 07:03 PM PDT
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Saturday, April 16, 2016

How does toothpaste affect the microbial flora of the mouth?

How does toothpaste affect the microbial flora of the mouth?

How does toothpaste affect the microbial flora of the mouth?

Posted: 15 Apr 2016 10:15 AM PDT

Hi! I'm a microbial ecology M.Sc. candidate that works predominantly in soil. In soils, there is quite a bit of evidence that anthropogenic changes to the soil affect the microbial community and it seems (at least from what I read and work on) that this can sometimes severely limit the diversity of microbes to species and genera that are capable of withstanding the changes. For example fertilization can limit the ammonia oxidation community to a small subset of species that are capable of surviving at high ammonia concentrations and make better use of the substrate.

The human microbiome is a pretty interesting subject to me even though my understanding of it is pretty limited. I've always wondered about toothpaste. I'm not sure what sorts of antibacterial properties it has and what exactly it's supposed to be doing to teeth... Does brushing your teeth 1 to 3 times a day cause the microbial community to shift towards species that can resist the perturbation? Could this practice cause us to have higher concentrations of bacteria that have negative effects on our health and hygiene (such as increasing the proportion of bacteria that cause bad breath or tooth decay)? It seems pretty amazing to me that we still follow a practice that has been around since before PCR and as far as I know, we kind of just accept it.

Please enlighten me!

Edit: As I watched the upvotes climb and the comments stay at 0, I thought about the similar scenario with soap. We wipe out most of the microbes every time we wash and let them colonize anew. I remember seeing some evidence that some bacteria metabolize odour-causing chemicals, but that by washing the "bugs" away, we end up stinking when we're no longer "clean". There is anecdotal evidence from a reporter that tried not washing with soap for a while and after a few weeks of applying bacteria (coincidentally the same ones I study in soil), when his skin microbiome had reached some sort of equilibrium (presumably), he stopped stinking.

submitted by /u/GreatAssGoblin
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How did the ancients discover the value/concept of Pi? In what ways was it useful to their lives?

Posted: 15 Apr 2016 04:36 PM PDT

What makes electomagnetic waves able to propagate without a medium and other not other waves??

Posted: 16 Apr 2016 03:50 AM PDT

What two creatures are most closely related genetically, but look the most different physically?

Posted: 15 Apr 2016 10:23 AM PDT

Is there any evidence of two seperate planets orbiting an object in the same path but not colliding?

Posted: 15 Apr 2016 03:23 PM PDT

Are there the same number of Protons as Electrons in the Universe? If so, why?

Posted: 15 Apr 2016 02:39 PM PDT

This article (http://cosmology.berkeley.edu/Education/CosmologyEssays/The_Standard_Cosmology.html) states that Proton creation and Electron creation after the Big Bang occurred on different schedules. As such, there would seem to be no reason for their numbers to be equal. Are they equal and, if so, why?

submitted by /u/dgm42
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What happens when you use ackermann's function with graham's number as it's arguments?

Posted: 15 Apr 2016 03:42 PM PDT

How does nuclear binding energy work and what are it's uses?

Posted: 15 Apr 2016 11:30 AM PDT

Is there a way to do floor and ceiling functions using only 4 operators ( + , - , * , / )?

Posted: 16 Apr 2016 12:49 AM PDT

How do electrostatic forces play a role in accretion and agglomeration of cosmic dust?

Posted: 15 Apr 2016 02:56 PM PDT

This has a few parts to it....

first, how does the charge get attached to the dust?

Second, if like charges repel, and unlike charges attract, how is it that the asymmetry of charges comes about which allows particles to stick together? Shouldn't a similar charging process make it so that the cosmic dust is charged with like charges making it repulsive?

another related bonus question: how are dust bunnies formed?

submitted by /u/portmantoux
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What rare elements are used in modern CPU and GPU designs, and are there viable substitutes?

Posted: 15 Apr 2016 08:54 AM PDT

There has been a lot of talk about things like Indium for transparent semiconductors becoming scarce, but what about the most crucial chips in computing, the CPU and GPU? I know the chips are mostly made from silicon with small amount of dopants, but are these particular dopants rare, and how long could we go if they continue being used at accelerating rates?

Moreover, supposing we wanted to change to a more sustainable alternative, do they exist? Could you make today's high-speed microchips with commonly available elements, or are we basically boned if we run out of certain rare earth metals?

submitted by /u/slugwind
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Do each of our nerves have separate connections to the brain or do signals travel up a common pathway?

Posted: 15 Apr 2016 08:20 AM PDT

For the moment I'm considering our senses of touch, hot, cold...

If the signals merge into some kind of central line then they would have to have some method of telling the brain where they originated. Otherwise, there must be a TON of wiring going up there!

submitted by /u/ace_urban
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How does the stop/start technology work in a modern car and why isn't the radio cut off when it starts again, like when I start an older car?

Posted: 15 Apr 2016 08:16 AM PDT

Does saltwater have a net electrical charge? If so, how would you go about calculating it?

Posted: 15 Apr 2016 02:17 PM PDT

Title

submitted by /u/50Genie
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If most average galaxy groups are discovered to contain supermassive black holes, like the recently measured NGC 1600, would that provide any evidence to contradict our current theories of dark matter being primarily nonbaryonic?

Posted: 15 Apr 2016 10:19 AM PDT

After reading about the recently measured supermassive black hole at the center of NGC 1600, which is considered to be surprising because it contradicts our current theories of such large black holes usually being found in large dense clusters, I wondered if this discovery (or, more accurately, the potential discovery of many more similarly-sized black holes in non-large and non-dense clusters) would have any impact on our current hypotheses that dark matter is likely comprised primarily of nonbaryonic matter. After reviewing the current evidence in favor of nonbaryonic dark matter (i.e., baryonic gas or dust would be visible, the observed abundance of chemical elements, not enough gravitational microlensing, and CMB anistropies showing most matter interacts only through gravitational effects), it seemed to a layman like myself that the potential discovery of supermassive black holes at the heart of most clusters, instead of only at the heart of large dense clusters, would offer evidence to refute these current lines of evidence. But I would appreciate someone pointing out how this would not, in fact, refute the current lines of evidence. Thank you.

submitted by /u/lonefeather
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Why do photons have energy?

Posted: 15 Apr 2016 07:56 AM PDT

Thinking about photons as a particle, they are massless (as in, I assume, they have no rest mass). So by E=mc2, they should have no energy.

The thought that comes to mind (and I've seen this 'explained' with), is that the actual form of that equation is: E2=m2c4+p2c2 Where more energy could come from the momentum of the photon. But isn't momentum defined as the product of the mass and the velocity? Is this different for photons, or is there another reason for their energy?

submitted by /u/BaconWraith
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Why is time not divided into tens?

Posted: 15 Apr 2016 03:48 AM PDT

One day has 24 hours, one hour has 60 minutes and one minute has 60 seconds. This makes it harder to convert a year into seconds. Or for example if you said 2.5 hours had passed it would actually be 2 hours and 30 minutes that has passed. This seems illogical.

In all European countries (as far as I know) we use the metric system which is basically everything divided into tens and makes convertion of meters to centimeters or any other conversion easy.

To me, it seems illogical not having time be divisible by ten. Is it because seconds (or rather centihours?(a hundredth of an hour)) would span such a short time it would be impossible to count?

Even seeing how much of the day has passed would be easier if you said there is 10 hours in 1 day. After 2.5 hours you would know that a quarter of the day has passed. And 2.5 hours would be 2 hours and 5 decihours. Or 2 hours and 50 centihours.

(Edit: fixed spelling errors)

submitted by /u/TheNumber999
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Friday, April 15, 2016

Does the mass of a black hole increase by any appreciable amount by absorbing photons?

Does the mass of a black hole increase by any appreciable amount by absorbing photons?

Does the mass of a black hole increase by any appreciable amount by absorbing photons?

Posted: 14 Apr 2016 01:24 PM PDT

We all know that light cannot escape from black holes. Over the course of tens/hundreds/thousands of millions of years, does a black hole absorb so much light that its mass could measurably increase?

submitted by /u/bluespartans
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When you find the sin of a cosine of a tangent of an angle - for any number so long as it's in degrees and not radian - why does the answer always approach 0.0174?

Posted: 14 Apr 2016 05:24 AM PDT

It can be done with any number, so long as you don't find the sin of a sin, or the cos of a cos, or the tan of a tan

What I mean is, you can do sin(cos(tan(sin(cos(tan(x))))))) for any combination of sin, cos, tan and get 0.0174 so long as there are no sin/cos/tan adjacent to each other. Why does this happen?

submitted by /u/h0ne
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How does a tempered glass screen for your smart phone pass the sense of touch to the sensors below?

Posted: 15 Apr 2016 06:44 AM PDT

The title pretty much sums it up. I can guess that it would be through heat or possibly shadow but I can't say for sure. It probably isn't from pressure because the tempered glass seems very hard and therefore wouldn't flex much.

submitted by /u/Year3030
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Could you put a wind turbine on a sky-scraper?

Posted: 14 Apr 2016 03:59 PM PDT

I'm wondering if it's economically and technologically feasible to put a wind-farm style turbine on the roof of a sky-scraper or other tall building to generate power for that particular building.

submitted by /u/TXLibertarian
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How do rocket engines prevent back-flow of ignited fuel?

Posted: 15 Apr 2016 12:26 AM PDT

In other words, how is ignited fuel stopped from flowing up the fuel lines? And also if it did, what would happen?

(Regard bi propellant rockets.)

submitted by /u/Revilokrik
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Have we seen evidence of a fourth or higher spatial dimensional universe by looking at everyday natural objects in this, our three dimensional visible universe?

Posted: 14 Apr 2016 03:54 PM PDT

4D objects theoretically can be seen in the third dimension which we live in, but we would only see a slice of the object. To us it would be 3D and natural. Are there certain geological shapes that regularly occur in this universe that point to a higher dimensional universe that we just can't see? If they point to a higher dimensional universe, do we simply dismiss this as having natural shape in a 3D universe. Could we be missing something right beneath our noses?

submitted by /u/washor
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What would be the smallest thing from which to observe the effects of time dilation?

Posted: 15 Apr 2016 06:07 AM PDT

I understand that atoms for instance with their half life could show wether they've "jumped ahead" in time... Or do they? I have this impression mainly because of the vague understanding I have on how atomic clocks work. But could you go smaller? Could a single subatomical particle show time dilation's effects?

submitted by /u/Mahtavaa
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If you placed our solar system much closer to the galactic core, what would be different?

Posted: 14 Apr 2016 03:10 PM PDT

Can information be transmitted through the weak or strong nuclear forces?

Posted: 14 Apr 2016 01:53 PM PDT

Seeing as we can measure the frequency of electromagnetic and gravitational waves and thereby transmit information using those forces, is it possible to do something similar with the weak or strong nuclear forces? Or do they only operate on a scale that prohibits useful applications?

submitted by /u/ThatOneStoner
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Did the earth's geological axis ever change? Could there be a 'wobble' and the poles shift?

Posted: 14 Apr 2016 03:39 PM PDT

For example, could the south pole been further north, like in Australia? (not a question about magnetic poles)

submitted by /u/magictron
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What are some of Newton's less famous discoveries?

Posted: 14 Apr 2016 10:22 AM PDT

Why is osmotic pressure divided by ZERO at the y-intercept in osmometry of polymers?

Posted: 14 Apr 2016 12:13 PM PDT

For determining the number average molecular weight of polymers by osmometry the following equation is used: (Pi/C) = RTA1 + CRTA2.

C is concentration of solute, A1 is first virial constant, A2 is second virial constant, R is universal gas constant and T is temperature.

The equation represents a straight line, where (Pi/C) is on Y-axis and C is on x-axis.

Doesn't that mean that the y-intercept is equal (Pi/0) at C=0, So how is it possible ?

submitted by /u/PureImmortal
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What are sugar's effects on our body?

Posted: 14 Apr 2016 12:35 PM PDT

I suppose this could be the wrong subreddit, but when I ask this question on google, all I get are clickbait lists and not-so-believable websites' takes on what could be the effects.

I'm just trying to figure out if I'm correct when I say that "Coke Zero is better at waking you up and keeping you awake than regular Coke because the sugar will eventually make you tired."

submitted by /u/ethret
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How do cation channels get specificity?

Posted: 14 Apr 2016 04:25 PM PDT

I understand that cations like Na+ will not go through Cl- channels because of cationic amino acid residues lining the Cl- channel pore, but how do cation channels select for 1 cation? Does Na+ flow through K+ channels? If not, what stops Na+ flow?

submitted by /u/patchitup
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Why can some mosquito species carry viruses like zika and other species are unable to carry it?

Posted: 14 Apr 2016 01:35 PM PDT

Why are the blades on hole punches a concave shape?

Posted: 14 Apr 2016 11:39 AM PDT

Are there any differences in language development between the genders during the early years (0-8 years)?

Posted: 14 Apr 2016 02:23 PM PDT

Hi, I am currently writing an essay on early years language development (0-8 years), more specifically on gender differences. Is there a clear scientific consensus on the differences? Who are the researchers, what major theories are there, is it all genetic or rather sociocultural? Thanks in advance!

submitted by /u/murcuo
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How does a neutron star die?

Posted: 14 Apr 2016 09:39 PM PDT

Why do certain faces scare us? Like a smiling face, a blurry face, or... No face?

Posted: 14 Apr 2016 12:28 PM PDT

These seem to be popular in horror movies/stories but I'm not sure why they are so terrifying

submitted by /u/Fitfarm
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