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Tuesday, May 17, 2016

Does the glass on a smartphone screen get thinner over time the more you touch it?

Does the glass on a smartphone screen get thinner over time the more you touch it?

Does the glass on a smartphone screen get thinner over time the more you touch it?

Posted: 16 May 2016 09:46 AM PDT

Where is the line drawn for what counts as one molecule? Is a full strand of DNA one molecule? Is the membrane for the nucleus?

Posted: 17 May 2016 05:14 AM PDT

I've heard grapes have more "coding genes" than humans. Do the human coding-genes form some kind of sub-set or overlap of the grape, or are the coding regions of the DNA/(genome?) completely different?

Posted: 16 May 2016 05:40 AM PDT

My question may not even make sense, because I think of the huge lists of base pairs being kind of like a book with ordered pages, which may not be the case.

But the idea that a grape is more genetically flexible or 'powerful' than us raises so many interesting questions in my (layman's) head:

Could you culture a grape (with perfect gene editing and knowledge) to be a human, but not the other way around?

Have the non-coding genes been found to have more function than 'junk' DNA?

How did the grape get more coding genes, anyway?

Are there generally more coding genes in plants or mammals? Seems counter-intuitive, but then I suppose a mouse is more similar to a human than grass is to a pineapple?

Sorry for the ramble. The main question I have is: Do the "coding genes" fall in roughly the same locations along the genome?

submitted by /u/isaidthisinstead
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Is Dark Energy a property of spacetime? Can Dark Energy be attributed to the Casimir Effect? Why use Mpl/(Lpl)^3 to discredit QFT explanations of DE? AND MORE!

Posted: 16 May 2016 07:15 PM PDT

Hey guys, I've now wasted my day off exploring our limits of understanding about Dark Energy and now have some questions that, hopefully, you wonderful people can answer for me. For reference, a good chunk of these questions arise from watching Professor Ed Copeland talk about Dark Energy in this video

Professor Copeland makes some assertions about Dark Energy:

  1. It's uniformly spread across the entire universe (its smooth).
  2. It's always been smooth (evenly distributed)
  3. It is not the dominate force in the universe but it will be due to the expansion of the universe. (energy density of matter and radiation drops as space expands)
  4. It weak in local systems with high mater density and strong in systems without a high matter density

On to my questions:

1) Is Dark Energy a property of space-time itself?

  • If DE is uniformly distributed, has always been uniformly distributed, and does not lose energy density as space expands, does this not spell out that space-time expands 'on its own'? It seems to me that the properties of DE are so different from matter or radiation in how they propagate across the universe that DE can't be a 'thing' but rather a property of how space-time acts.

2) If Dark Energy is a property of space-time, why not attribute it to the Casimir Effect?

  • So this question is a little loaded because I know that most physicists would point out that the Casimir Effect is ~7.2x10122 times stronger than DE seems to be. Lets just put that notion aside for a second (don't worry I'm coming back to it). The Casimir Effect is what happens inside a vacuum where particle pairs are spontaneously created from residual energy of the vacuum. These particle/anti-particle pairs are created for only brief periods of time (so short that they are referred to as virtual particles) but still exert a force on the system. Since the Casimir Effect is a property of space-time and will exert pressure, it seems like a great candidate for what DE is.

3) When asked why vacuum energy (Casimir Effect) doesn't explain DE, physicists say its too powerful and give an approximation on the Planck scale as verification

  • As the linked comment shows (I've seen a similar explanation in many other places as well), the classic rebuttal to vacuum energy is that its just way too strong. My problem is why in the world do we use mp/lp3 to explain why it is too strong. The Planck mass (mp) is the highest possible mass for a single-charge quanta and we are dividing it by the smallest possible volume? Why not use a mass of a proton or something much closer to what kind of particles the Casimir Effect produces? To me, if we divide the largest mass possible of a particle by the smallest volume that particle can occupy, of course we're going to get an extremely large number. I guess the question is: why is mp/lp3 used to estimate the Casimir effect?

  • Another thought of mine is: can we work backwards from the strength of DE to find what the Casimir Effect must produce to be similar/analogous to DE? Would this produce a viable result?

  • Tagging on to this, could particles that have m>mp interact with each other to form black holes, thus minimizing the net force of the Casimir Effect? Would these black holes have to evaporate (radiate away) extremely quickly to be viable?

4) If DE can't be contributed to the CE, are there any thoughts on whether space will expand on its own when given energy?

  • I still struggle with DE being something other than a property of space-time so I'm gonna follow that logic train for a bit. Could space-time itself be 'self expanding'? "Empty" space will spontaneously create particles, is there any reason not to think that it could also self-expand with the energy it has? Or maybe space-time is self-repelling? This question is similar to #1 but focuses on space being self-repelling or self-expanding specifically

5) OK, one last question and then I'll be quiet, promise. Why is a 'big-rip' a possibility with our understanding of DE?

  • DE is weak with high matter density systems (eg galaxy, solar system, moon systems, handshakes, etc) so how is it theorized that DE will overcome the strength of gravity and the other 3 forces? I understand local clusters drifting apart and galaxies drifting away from one another, but our galaxy is already held together by gravity. How is DE supposed to break up the milky way if the gravitational forces are too strong for DE to expand the galaxy as is. I guess a better way of putting it is: is our (or any) galaxy expanding due to DE already? If so, why isn't gravity preventing that expansion, isn't gravity currently too strong for DE to 'gain its momentum' and break up the galaxy?

Okay, that was really long, I apologize. I don't expect anyone to answer all the questions, but if you're willing to answer one or more, I'd be very appreciative for your time and investment in my learning.

PS: The bullet points are more or less my thought process behind each question so that you can get a better feel of where I'm at.

submitted by /u/DirtyJesus1
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Are there galaxies without a black hole in the center?

Posted: 17 May 2016 03:37 AM PDT

How the Schwarzschild Radius Formula was found ?

Posted: 16 May 2016 10:22 AM PDT

I was wondering if anyone could explain how Karl Schwarzschild ended up on this formula( R=2GM/c2) for the Radius to which you must reduce a object to make it a black hole . From what did he started ?

submitted by /u/matoussa71
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[Mathematics] What type of counting system do we use for time?

Posted: 16 May 2016 11:09 AM PDT

A little googling tells me its a sexagesimal (base 60 counting system) which to me fits fine enough for seconds and minutes, but when you include <microseconds and hours and days and such it becomes more complicated. I would call it a hybrid counting system, base ten for the first digit, base 6 for the second digit, twelve for the next two digits and so on and so forth. Is there an actualy term for this kind of counting system?

submitted by /u/Sman6969
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what is the concentration of fluoride require to prevent bacterial proliferation?

Posted: 16 May 2016 07:12 AM PDT

I also realize it could depend on the bacteria. So I also want to know how much. Maybe its almost none maybe its a lot.

Chose chemistry since ''biochemistry'' included. I guess cellular biology would not be far either.

submitted by /u/LOST_TALE
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What does the molecular structure of titanium look like? I can't seem to get a definitive answer using Google.

Posted: 16 May 2016 02:31 PM PDT

I tried Googling titanium molecular structure to mixed results, depending on the type of Titanium.

Here's the thing, I don't know what I'm looking for except that I have one titanium implant in my left ear and some titanium screws in my C spine.

I'd like to use the molecular structure in a piece of artwork I'm working on, but I'm not sure which one I should use.

Any ideas?

submitted by /u/12084182
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Why are the graphs of some functions not a single line?

Posted: 16 May 2016 05:30 PM PDT

The graphs of some functions are divided into individual lines, such as the graph of the tangent function, secant function, cosecant function, and cotangent function. In the case of tangent and cotangent, the graph looks like several lines that curve deeper the closer x approaches zero, and by mathematical law they will never touch. The same goes for secant and cosecant, only this time the graph of both resembles a layout of multiple parabolas whose vertex has an absolute value of 1. Just like tangent and its reciprocal, the individual lines that make the graph never touch each other. In general, the graph of each of these functions is broken up into individual lines. My question is, why? Why aren't the graphs of these functions (and so many more) united as a single line?

submitted by /u/4w350m3guY
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How can I calculate the optimal path for a particle through a set of points?

Posted: 16 May 2016 07:41 PM PDT

Given a set of points on a 2D plane, and assuming no friction, how would I go about finding the quickest (or at least a close to optimal) path for a particle through these points assuming that I can change the angle of acceleration as well as the amount of acceleration up to a constant.

For example, say I am flying a rocket and I want to get from point A through point B to point C. I can control which way the thruster is oriented and I can change the thrust value from 0 to k:

- - - - - - - - - - - - - - - B - - - - A - - - - - - - - - - - - - - - - - C - - - - - - - - - - -

The optimal path would be some sort of curve from A to C passing through B. What sort of a curve am I looking for and how could I calculate it? Even some search terms and suggestions would be useful.

submitted by /u/Russian-Assassin
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How is it that scientists can say that there are more dimensions than our own? What proof is there and where can I find it?

Posted: 16 May 2016 09:28 PM PDT

If we have the technology to image the handful of individual stars as they closely orbit around the black hole at the center of the Milky Way, why hasn't there been a concentrated effort to map all stars on our half of the Milky Way?

Posted: 16 May 2016 04:54 PM PDT

If we can precisely image these stars which are 25k light years away, then shouldn't it be possible to precisely determine the position of all stars within 25k light years?

That would equal half our galaxy.

submitted by /u/woofwoofwoof
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What is so big about absolute zero?

Posted: 17 May 2016 05:12 AM PDT

What kind of advancement(s) would be made if we were to reach it, which I know can not be done

submitted by /u/720no_scope
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Why don't grains of salt stick together, if they are formed through ionic bonds?

Posted: 16 May 2016 09:21 AM PDT

Also why does Na and Cl form crystals?

submitted by /u/Mir3al
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[Physics] Is it possible that the information in the brain survives death? Sean Carroll says we know and understand every particle/force/field that *could* interact with the brain. As a result, if this information were being carried away after death, we could detect it.

Posted: 16 May 2016 10:53 AM PDT

Is it possible that the information on the brain survives death? Sean Carroll claims that although there is a lot of physics we don't understand, we know and understand every particle/force/field that could interact with the brain. As a result, if this information were being carried away after death, we could detect it. He says (in the video below) that if this mystery particle existed you would be able to collide the particles that make up the atoms of the brain and it would generate this mystery particle. He shows rotating a Feynman digram to demonstrate this idea.

Here is a link to a recent article where he mentions it: http://www.npr.org/sections/13.7/2016/05/15/478143589/fear-of-knowing

Here is a link to an older video where he goes into much more detail: https://youtu.be/Vrs-Azp0i3k

If he is right, why isn't this more widely discussed? If he is wrong, I want to understand why. Thanks for sincerely evaluating this.

submitted by /u/BeakOfTheFinch
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Why are there waves in this water?

Posted: 16 May 2016 08:34 AM PDT

Somehow, the people in this video are riding the very first wave just behind completely still water.

https://youtu.be/GmBWvF6-4DQ?t=155

What could possibly cause this uniform wave pattern that has a beginning?

submitted by /u/TechnoL33T
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I have a hula-hoop of power cable. If I turn it (fastly) around me, can I induce a current? Does this induce a magnetic field? How much energy could I produce/convert?

Posted: 16 May 2016 08:36 AM PDT

Let's treat this like a physics problem in school, so please assume a spherical power cable in a vacuum.

This question could be really dumb... if so, please explain why. Will it work similar to a dynamo?

submitted by /u/DeutschLeerer
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What is the Grand Unified Theory?

Posted: 16 May 2016 05:42 PM PDT

Hello all, I am doing a presentation on the Grand Unified Theory and I am wondering if there is any essential information I should include? Also is there any basic analogy I can relate to this theory to give the class I am presenting to a better understanding of the topic? Thanks in advance.

submitted by /u/jonnyfolsom
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Is there a map of the known universe as it "is" vs what it "was"?

Posted: 16 May 2016 05:47 AM PDT

Every time I see that cool 3D map of the universe, it is prefaced with, "we are looking into the past". While that's cool and all, we do know the location, approximate distance, and approximate direction of travel and speed. Has anyone ever "advanced" the map to where everything is (or should be) positioned today?

submitted by /u/ABrownCoat
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vào lúc No comments:

Monday, May 16, 2016

Is it possible for a star to be cold?

Is it possible for a star to be cold?

Is it possible for a star to be cold?

Posted: 15 May 2016 09:15 AM PDT

If it is, is the limit absolute zero? And a follow-up, is there any limits on how HOT things can be?

submitted by /u/JebbeK
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Why is a full circle 360 degrees? Why not just a round number like 100 or any other number?

Posted: 15 May 2016 10:05 AM PDT

On a molecular level why is inhaling Cyanide (HCN), even in small amounts, so dangerous to humans?

Posted: 15 May 2016 05:59 PM PDT

At least with Carbon Monoxide it takes a lot to really do damage but Cyanide seems like one whiff is enough.

submitted by /u/MartinBrodyMcFly
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When did we first hypothesize that most galaxies have a supermassive black hole at the center?

Posted: 15 May 2016 07:06 PM PDT

I know that Maarten Schmidt discovered the first quasar in 1963, and astronomers wondered how it could be so bright being so far away (2.5 billion light years), which led them to hypothesize that it could be powered by an accretion disk spinning around a supermassive black hole. How did we make the jump from there to the general acceptance that all or most galaxies have a supermassive black hole at the center?

submitted by /u/ScruffyMcScruffkins
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Why is my salt leaving my salt shaker?

Posted: 15 May 2016 04:02 PM PDT

The salt is slowly climbing up the wall of the shaker and out the lid. What chemical process is causing this to happen? http://imgur.com/On9qSsk

submitted by /u/cambardell
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Is there a name for all animals that lay eggs?

Posted: 15 May 2016 04:49 PM PDT

What's the word for all the fish, birds, reptiles, and amphibians that lay eggs, or anything that isn't a mammal.

submitted by /u/OliveEyes-
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If tectonic plates didn't move, would Hawaii be taller than Olympus Mons?

Posted: 15 May 2016 06:07 AM PDT

Assuming that Hawaii was still continuously fed by mantle material. Or would gravitational instability prevent such heights?

submitted by /u/forams_galorams
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Does meteoric water infiltration significantly affect fault characteristics?

Posted: 16 May 2016 01:37 AM PDT

A 2016 paper looking at meteoric water input into the Alpine fault of New Zealand has a weakish byline in its summary stating:

"Focused fluid flow through the Alpine Fault zone may promote fault weakening by facilitating the formation of weak secondary minerals and promoting the generation of high pore fluid pressures or pressure compartmentalisation"

Does the paper/any evidence available strongly promote the theory? Do you think that the effect significantly affects fault characteristics? For example, might it reduce the critical stress required to rupture, and therefore the magnitude of ruptures?

http://www.sciencedirect.com/science/article/pii/S0012821X16301418

submitted by /u/seraillier
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Pythagorean triples: what is the geometric meaning of Euclid's formula?

Posted: 15 May 2016 03:03 PM PDT

Euclid's algorithm for generating Pythagorean triples is well known --

For all m and n<m, {2mn, m2-n2, m2+n2} generates an integer Pythagorean triple.

The algebraic validity of this is pretty obvious, but do m and n in this formula have any geometric meaning? If I'm looking at a right-angled triangle ABC, can m and n be made to correspond to anything in the diagram?

submitted by /u/Zikzax
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How accurate is the concept behind Discovery's "Sonic Sea"?

Posted: 15 May 2016 01:40 PM PDT

I just saw this video on Facebook which details the ways in which humans add noise pollution to the ocean. The trailer definitely does its best to make the problem sound really bad, but it seems to me as though the vastness of the ocean would make human noise pollution a pretty insignificant problem for whales and other species that rely on sonic communication. Have there been any studies that have definitively demonstrated that ships and/or oil prospecting provide a significant disruption to whales' (or other marine species') ability to communicate?

submitted by /u/ravenpride
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Sterilisation and hysterectomy?

Posted: 15 May 2016 03:22 PM PDT

Context: Roughly in the '60s and '70 disabled female residents living in institutions in Japan were sterilised without consent. I have a source which speaks about sterilisation and a source which uses the term "hysterectomy". Can hysterectomy be a way of sterilisation or are they two different things? I'm confused if they used both (unmentioned) ways of sterilisation and hysterectomy, or only the later. The reason stated in both sources is that it was done to ease (the menstrual pain and) the workload of the workers. Also gave the institutions free guinea-pigs since the parents' had usually signed a waiver that gave permission to perform any surgeries on residents. It's terrible I know.

(English isn't my first language and I'm not that familiar with this sort of terminology. Sorry and thanks!)

submitted by /u/nietzschetsefly
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If current is the flow of electrons why does it flow in the opposite direction as electrons?

Posted: 15 May 2016 10:21 AM PDT

I know that electrons go from negative to positive because of electrostatic repulsion and electrons carry a -ve charge.

But my textbook says that current is the "flow of electrons", wouldn't that mean it also flows from negative to positive?

submitted by /u/7df1
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Does the temperature of water affect it's viscosity?

Posted: 15 May 2016 06:32 AM PDT
vào lúc No comments:

Sunday, May 15, 2016

If diamonds are the hardest material on Earth, why are they possible to break in a hydraulic press?

If diamonds are the hardest material on Earth, why are they possible to break in a hydraulic press?

If diamonds are the hardest material on Earth, why are they possible to break in a hydraulic press?

Posted: 14 May 2016 07:42 AM PDT

Hydraulic press channel just posted this video on Youtube https://www.youtube.com/watch?v=69fr5bNiEfc, where he claims to break a diamond with his hydraulic press. I thought that diamonds were unbreakable, is this simply not true?

submitted by /u/ObscureClarity
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I understand trigonometry and it's identities but I am having trouble understanding it intuitively. I've read and seen all the unit circle definitions and I grasp that perfectly. It's just that, I'm looking for an explanation that doesn't rely on geometry?

Posted: 14 May 2016 07:52 AM PDT

An explanation without triangles and circles.

submitted by /u/thehighschoolgeek
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Is it theoretically possible to freeze photons?

Posted: 14 May 2016 08:28 PM PDT

Do elementary particles freeze at absolute zero? Can we [humans] ever go sub absolute zero?

submitted by /u/stuffdude99
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If I dropped a lamp into a black hole and a photon left the lamp travelling *exactly* away from the singularity, after the lamp had passed the event horizon, would the photon slow down or leave the black hole?

Posted: 15 May 2016 04:11 AM PDT

What would be the toughest material of the diamond-sized object for the hydraulic press to break?

Posted: 14 May 2016 12:26 PM PDT

How are the images on the Voyager probe kept?

Posted: 15 May 2016 12:03 AM PDT

I've tried researching how they're kept, but all the sources say they're on the phonograph record. Are the images on film, a metal plate, etc?

submitted by /u/boeing186
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How can a whip wrapping around an object, Indiana Jones-style, be analyzed through kinematics of motion? Are there any equations for this?

Posted: 14 May 2016 06:47 PM PDT

I'm more so asking about the impact force as the whip coils around the object, as there's already lots of info on reddit for after it is wrapped around.

submitted by /u/InsanityIsPresent
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Is it pitch black in between stellar systems?

Posted: 14 May 2016 11:43 AM PDT

NASA posted this picture of a black hole to their Instagram account. Is it real? Fake? Have we observed black holes?

Posted: 14 May 2016 12:33 PM PDT

And also, if it was a computer generated approximation of what a black hole galaxy may look like, wouldn't it be a little bit disingenuous of them to present it like a "picture" - like the real images of space on their profile?

Picture here

submitted by /u/airconditioning8
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Is it theoretically possible to write an algorithm that returns a random number without restrictions?

Posted: 14 May 2016 11:15 AM PDT

Without restriction means no pre-specified length, precision, range etc.

submitted by /u/Sipczi
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How is C^13 - O^18 isotope clumping used as a Paleothermometer?

Posted: 14 May 2016 07:48 AM PDT

Just read the article by P. Ghosh et al. but struggling to get my head around the concept, as Chemostratigraphy isn't my forte at University.

submitted by /u/RowanHawker
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Why does mesosphere lightning look different to normal lightning?

Posted: 14 May 2016 11:05 AM PDT

Normal lightning is blue and tree-like. Mesosphere lightning looks like terrifying red alien squid. Why do they look so different?

submitted by /u/gatherinfer
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Does the maximum size of a droplet from a water-solution increase with the amount of non-water particles in said solution?

Posted: 14 May 2016 09:08 AM PDT

How do I calculate the "heat transfer" function for a tank of gas?

Posted: 14 May 2016 07:14 AM PDT

I have some sensors installed on a carbonation system that's installed in a remote location, effectively outside.

Specifically, we'd like to be able to estimate the amount of gas remaining and track usage in the tank. The tank in question is what I would call a 280 of CO2: the tank holds about 280 cubic feet at atmospheric pressure, but is a heavy steel tank about 300mm in diameter and about 1.5m tall.

You can estimate tank fill by measuring the tank pressure-- at about 1000psi, the tank is full. At 0psi, the tank is empty.

All that said, we're seeing dramatic changes in tank pressure based on the air temperature. These changes are completely masking the gas usage. We can still determine when the tank needs to be replaced, but I'd really like to be able to estimate gas usage on a daily or weekly basis.

See charts here -- top is pressure in psi, bottom is temperature in C. The temperature sensor is near to the tank. Visually, you can see that the tank pressure generally follows the temperature, but it lags a bit due to the thermal mass of the tank. The gas isn't getting pulled out fast enough for the evaporation/decompression cooling to really affect stuff.

Given all that: is there a way to model or estimate the "heat transfer function" of the tank so we can remove the temperature signal from the pressure?

Raw data is here if you want to play: https://horat.io/data/pressure.txt https://horat.io/data/temperature.txt

submitted by /u/birdbrainlabs
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How can Dark Energy both be gravitationally repulsive and make up 70% of our Universe's mass?

Posted: 14 May 2016 12:12 PM PDT

Dark Energy makes up 70% of our universes' mass-energy and in all the articles I've read it is described as a field filling space with a (positive) energy density. Anything with positive mass or energy is gravitationally attractive, so how is Dark Energy gravitationally repulsive? Is it an example of negative mass?

submitted by /u/TheUtilitaria
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How does light act as a particle?

Posted: 14 May 2016 09:49 AM PDT

Light is commonly stated to act as a particle and a wave, possessing properties of both. I (think I) understand ways it acts as a wave, as shown in double split experiments, but I can think of no way it acts as a particle. Anything would help. Thanks

submitted by /u/jeenyus024
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Relationship between band gap and color?

Posted: 14 May 2016 11:28 AM PDT

What is the relationship between the band gap and color of a material and why does this relationship exist?

submitted by /u/mathematicalNonsense
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Why is it that when a sea wave crashes into the beach, the water turns white momentarily?

Posted: 14 May 2016 08:14 AM PDT

When a sea wave crashes into the beach, it forms a lot of foam like substances, and turns white, can anyone explain this? I hypothesise that it has something to do with air being dissolved into the water when the wave crashes, but unable to proceed further. Thanks!

submitted by /u/wormta
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vào lúc No comments:

Saturday, May 14, 2016

What would be a 2D equivalent of a black hole?

What would be a 2D equivalent of a black hole?

What would be a 2D equivalent of a black hole?

Posted: 13 May 2016 11:43 AM PDT

You know how sometimes gravity is portrayed on a trampoline, with a big ball placed in the middle to warp the sheet and a small one going around it in circles to represent a planet, right?

What would be the equivalent of a black hole in that representation?

submitted by /u/macko939
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I know that carbon, under extreme heat and pressure, can form diamond. Is there a similar transformation with other elements?

Posted: 13 May 2016 11:07 AM PDT

I was particularly interested in finding out if lead could also make a similar transformation under extreme heat and pressure and if so, what the result would be.

submitted by /u/ClaytonWHanna
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Would a triangle of degrees 0°, 0°, and 180° (a line by all appearances) still be considered a triangle?

Posted: 13 May 2016 06:25 PM PDT

Casimir confusion: how is it even possible?

Posted: 14 May 2016 01:49 AM PDT

My understanding may well be flawed, but I have been told:

  • Heisenberg uncertainty implies all harmonic oscillators, including electromagnetism in free space, have non-zero minimum energy.
  • Two conductors placed next to each other block some of those oscillations between them, producing a net force.

My expectation is that the conductors should be incapable of blocking the oscillations for the same reason those oscillations exist in the first place. This is a widely discussed model so I recognise I'm probably wrong, even though I don't know where my mistake is.

Is this related to why some people say "it's all van der Waals forces, nothing to do with quantum effects!"?

submitted by /u/furvert_tail
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There's lots of work on the physics of having more than 3 spatial dimensions. Is there any work on the physics of having more than two temporal dimensions?

Posted: 13 May 2016 08:40 PM PDT

E.g., some string theories tell us that the universe might be 10+1D—ten space dimensions, one time dimension. Has there been any theoretical work on the physics of a universe that's, for example, 3+2D (or more generally, x+yD where y>1)?

submitted by /u/FluidChameleon
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Is there any way in how we could observe dark matter since it doesn't interact with anything besides gravity?

Posted: 13 May 2016 04:24 PM PDT

By observe I mean seeing it's particles or what ever it is like we can see quarks by smashing other particles and etc.

submitted by /u/The_Saviour
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Am i correctly following Newton's Laws?

Posted: 13 May 2016 03:50 PM PDT

I recently just got into physics (I'm 16) and was told that the earth (gravitationally) is just as attracted to us as we are to it (around 9.8m/s2) If this is the case, using f=ma or a=f/m i came to the conclusion that the earth accelerates towards us at a speed of approximately 1.633333 x 10-24 metres per second squared. This sounds reasonable but i was just wondering if this is accurate in any way?

submitted by /u/Aidquan
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[Physics] Is anything in the universe completely stationary?

Posted: 14 May 2016 05:04 AM PDT

How are the methods of integration and differentiation derived?

Posted: 13 May 2016 12:36 PM PDT

I'm assuming you can, but what I'm curious about is how one can know that the integral of x2 for instance is 1/3 x3 + c, and conversely the derivative of x2 is 2x. How do we know that you carry the power down into a constant and then subtract the power by 1 (other than "it just works")? Where did these methods come from? Chain rule? Product rule?

submitted by /u/UnclePutin
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If the Earth was compressed into a black hole, would it continue to orbit the sun?

Posted: 13 May 2016 06:57 PM PDT

If the earths mass was compressed into an area smaller than its schwarzschild radius while still orbiting the sun, assuming that the black hole did not lose any mass due to evaporation, would it continue its orbit unaffected?

submitted by /u/kirkHAM
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Why do the recently detected gravitational waves lose energy over time?

Posted: 13 May 2016 10:15 PM PDT

From what I understand the amplitudes of these waves begin very large but then dissipate as they propagate further from their point of origin. Where does the corresponding energy go? Is its transformation an intrinsic property of spacetime or the result of collisions with objects having mass? Is the reduction of their energy constant in all directions?

submitted by /u/Ribbing
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How deep can a chasm caused by an Earthquake be?

Posted: 13 May 2016 09:29 PM PDT

In the moviie San Andreas there's an earthquake where two plates move away from each other and things fall into the abyss. In real life, how deep can these get?

submitted by /u/squidwardtentickles
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Why is x*y=y*x? Is there a proof for this?

Posted: 13 May 2016 12:02 PM PDT

I know that if you multiply numbers, the order of these numbers doesn't change the result. For instance, 3x5=5x3=15. But why is this? And is there a proof?

Edit: forgot "x" between numbers.

submitted by /u/boytoy1
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Why do sleep-talkers speak sometimes normally and sometimes nonsense gibberish? Does the gibberish have any sort of "grammar"?

Posted: 13 May 2016 04:58 AM PDT

Earthquake Monitors at Bottom of Marianas Trench?

Posted: 12 May 2016 11:22 PM PDT

Hi, So I recently have been looking at alot of videos on tsunamis, particularly the one that almost hit Guam back when my family was stationed there in 2011. An that led to Earthquakes. Which led to me reading about Earthquake monitoring technology. From my understanding Earthquakes develop deep into Earths crust and the upper mantle. And the majority of them originate in the pacific ocean. From my current knowledge Earthquakes can only be predicted minutes before they happen, And there are a few ways that they can be predicted, most of which rely on fault lines. My proposal is to place monitoring devices along the Marianas Trench, the deepest point on Earth, I understand that there is immense pressure down there, but we have made strong enough cameras to dive to challenger deep before so I assume this would be possible. The trench is much deeper than other fault lines and in theory should give much more response time to pacific islanders, and possibly enough for a helicopter to catch footage of a Tsunami formation, something that has never been caught before up close. Please let me know if my reasoning is completely flawed or if this is already happening, I'm only 14 so there's a good chance I'm completely wrong :)

TL:DR I have an idea to place Earthquake monitoring devices along the Marianas trench to give more Earthquake response time to Pacific Islanders.

submitted by /u/TheSphericalCuber
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Why do the seasons match up with the length of the year?

Posted: 13 May 2016 11:12 AM PDT

So as I understand it the seasons are caused by the tilt of the earths axis. As it goes around the sun it wobbles (the axis) so that during the summer (I live in the US) the northern hemisphere is tilted closer to the sun and in the winter it's tilted away.

My question is why is the period of the wobble of the axis the same as the period for the earths orbit around the sun? Or, at least, they seem to be the same, summer and winter are during the same months every year.

submitted by /u/suds5000
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