Ok, let's try this again. I'm taking physics questions (If they arent fucking retarded).

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Physics Guy Wed Feb 16 22:25:37 2011 No.2549605 [Reply] [Original]

Ok, let's try this again.

I'm taking physics questions (If they arent fucking retarded).

>>	Anonymous Wed Feb 16 22:26:37 2011 No.2549614 What do you think is space made of? Do you think space is like some sort of liquid of is liquid like a some sort space?

>>	pascal !n5Z3VuZapw Wed Feb 16 22:26:37 2011 No.2549611 Why does gravity feel stronger when you are on the edge of a tall building? or is it psychosomatic?

>>	Anonymous Wed Feb 16 22:27:37 2011 No.2549617 >>2549614 >or sorry it's 4am here and i havent sleeped

>>	Anonymous Wed Feb 16 22:28:37 2011 No.2549619 I'm made mostly of space, and so are walls. Why can't I walk through walls?

>>	Anonymous Wed Feb 16 22:28:37 2011 No.2549620 What, exactly does the Uncertainty Principle say? How is this expressed mathematically? How and where do we lose the "missing" variables so that information is undefined?

>>	Anonymous Wed Feb 16 22:30:37 2011 No.2549624 >>2549605 what is the most challenging physics idea/topic you've ever studied? what is your favorite physics idea/topic?

>>	Anonymous Wed Feb 16 22:31:37 2011 No.2549628 Are physicists close to a complete model of the universe (such as finding the higgs boson)? What is the basic outline of such a model? In other words, what role does antimatter, time, and multiverse branes play in our current understanding?

>>	Anonymous Wed Feb 16 22:32:37 2011 No.2549632 Explain the dielectric constant

>>	Anonymous Wed Feb 16 22:32:37 2011 No.2549635 What is the turnover rate in the physics major?

>>	Anonymous Wed Feb 16 22:32:37 2011 No.2549638 Why do all physics problems involve ideal situations? Are all physicists just pussies who can't handle the real world?

>>	Anonymous Wed Feb 16 22:35:37 2011 No.2549647 >>2549619 I can answer that one. Even though these atoms aren't touching they still have a force, and these atoms combined have a force that prevents the wall going through your atoms.

>>	Physics Guy Wed Feb 16 22:38:37 2011 No.2549659 File: 111 KB, 319x353, 1267062363797.gif [View same] [iqdb] [saucenao] [google] >>2549611 >>2549611 Mostly psychosomatic, you shouldn't be able to precieve such small changes in gravity.

>>	Anonymous Wed Feb 16 22:40:37 2011 No.2549668 Aren't you the guy who works at CERN?

>>	Anonymous Wed Feb 16 22:40:37 2011 No.2549671 >>2549620

>>	Anonymous Wed Feb 16 22:41:37 2011 No.2549675 >>2549638 >Still in high school

>>	Anonymous Wed Feb 16 22:43:37 2011 No.2549684 Why can't people just accept that everything is made up of Strings?

Anonymous Wed Feb 16 22:52:37 2011 No.2549727

>>2549638
Actually, we have many ways of dealing with non-ideal situations. In quantum mechanics, it's called perturbation theory.

>>2549620
A full derivation of the Heisenberg unsharpness principle is a bit tedious and boring. It has to do with something called commutation relations. While for numbers it's true that a times b is the same as b times a, that's not true in the math physics uses. Physically, it's because a wave can be expressed either in terms of it's spacial or wavelength distribution. These are equivalent and provide the same information. It's great to be able to express something one way, and then another way when you want to do something else. However, this transition comes at a cost. What the principle really says is that to specify something very accurately, the property that lead it to be in that state becomes less and less certain.

Physics Guy Wed Feb 16 22:55:37 2011 No.2549748
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>>2549619
Electrostatic replusion

>>2549620
Uncertainity isn't a measurement problem.
The problem arises in the way the universe operates, not how we precieve it.

The "varibles" themselves aren't naturally "defined", they actually don't exist, unless we need them to exist.

Anonymous Wed Feb 16 23:00:37 2011 No.2549776

>>2549748
How can you say these "variables" don't exist? An electron in my computer is a lot different from one in my keys. The spin of an electron has very real consequences. They may not be the best way to describe things, but they certainly correspond to very real things.

>>	Anonymous Wed Feb 16 23:00:37 2011 No.2549773 Do we know what quarks are made of or why they have different masses?

>>	Anonymous Wed Feb 16 23:00:37 2011 No.2549771 Is the transition of electrons to different orbitals represented by the destruction of the original electron and the creation of an electron with a corresponding energy difference?

Physics Guy Wed Feb 16 23:03:37 2011 No.2549791
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>>2549628
Yes, the model is called the standard model.

Anti-matter is fucking everywhere, that shit is trivial. It behaves just like regular matter, just with some sign switches. It also can be thought of as regular matter, propagating backwards in time.

Time is to space, as imaginary numbers are to real numbers. The "unique" properties of time arise from the way we percieve imaginary numbers. We need to take "norms".

Multiverse branes are not part of physics. String theory is not considered "known physics", as it has no validiation whatsoever. Until we can actually experimentally confirm some of its tenets, it is just fancy math, not science, not physics.

>>	Anonymous Wed Feb 16 23:05:37 2011 No.2549808 >>2549776 not op, but electrons are not tiny little spheres. they exist as probability clouds. When they are "observed" (when something interacts with them) their waveform collapses.

>>	Anonymous Wed Feb 16 23:05:37 2011 No.2549813 ITT: Physics undergrad with an elementary understanding of Physics who thinks he knows Physics well.

Physics Guy Wed Feb 16 23:14:37 2011 No.2549873
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>>2549776
The value of spin (z-spin) of an electron doesnt exist, until I choose my z axis, and then take a measurement of it. Once I measure, I set the value of z-spin for all subsequent z-spin measurments (until I measure the x or y spin).

The universe only allows me to measure one componet of spin at a time. And when I do, the other componets become nonsensical. If I try and measure z then x, I will destoy the z value.

In it natual form, the x,y,z spin do not have percise values assigned to them. It is only through measurment that we set the values of some, and make the values of others impossible to measure.

>>	Anonymous Wed Feb 16 23:15:37 2011 No.2549886 >>2549813 But I knows my physics.

>>	Physics Guy Wed Feb 16 23:17:37 2011 No.2549895 File: 65 KB, 479x600, 1293589270070.jpg [View same] [iqdb] [saucenao] [google] >>2549813 Nope I work at the LHC, in experimental particle physics.

>>	Anonymous Wed Feb 16 23:22:37 2011 No.2549921 Is the information entropy representation I see of black holes at all realistic? Do you think there is any grounds to the idea (followed by say Wheeler) that deals with information being the fundamental reason for all we observe in physics?

Physics Guy Wed Feb 16 23:27:37 2011 No.2549950
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>>2549638
>Why do all physics problems involve ideal situations?

They don't. Only very very very basic physics uses ideal situations. And they just use it as a stepping stone for teaching purposes.

>>	Physics Guy Wed Feb 16 23:28:37 2011 No.2549957 File: 51 KB, 324x456, albert-einstein_on-bicycle3_19043720.jpg [View same] [iqdb] [saucenao] [google] >>2549668 Yes, I work at CERN.

Physics Guy Wed Feb 16 23:32:37 2011 No.2549983
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>>2549684
>Why can't people just accept that everything is made up of Strings?

Cause we have no evidence validating string theory. No evidence whatsofucking ever.

A scientific theory needs validation as well as predictive power. Our leading theory is the standard model, which has literally a shit ton of supporting evidence and predictive power. It is the most sucessful scientific theory ever developed (as least most of it and the electromagnetic sector).

>>	Anonymous Wed Feb 16 23:34:37 2011 No.2549994 If you were forced to change fields, which would you choose and why?

>>	Anonymous Wed Feb 16 23:34:37 2011 No.2549997 Not sure if this is physics or not but... Is there a name for the effect that when something is very very far away like the moon or stars if appears to follow you? Is there a name for that?

>>	Anonymous Wed Feb 16 23:36:37 2011 No.2550007 >>2549957 How do you get a job at CERN? Are most of the poeple that work there assholes or bros? What did you do today/last day of work?

Anonymous Wed Feb 16 23:36:37 2011 No.2550008

I've heard that the equation for finding the gravitation influence of a black hole has a denominator of r, where r is the distance to the black hole's center. What happens when you are at the center, and r=0? I dont understand how something in nature can be undefined

Physics Guy Wed Feb 16 23:37:37 2011 No.2550015
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>>2549921
>>2549921
Sorry, havent really followed that. I know a shit ton about the black hole infomation paradox, but not extacly sure what you are refering to.

Any fundemental idea that involves entropy is usually shit teir. Entropy is not a fundmental property/idea, it is not first principle.

>>	Anonymous Wed Feb 16 23:38:37 2011 No.2550022 >>2550008 When something in physics is undefined, it means our model is inaccurate.

Anonymous Wed Feb 16 23:38:37 2011 No.2550019

so they other day i was thinking about what the smallest unit of length is. mathematically you can always get smaller by dividing by 2 again.
so my point is i'm thinking at some small length space tends to get fuzzy instead of discrete.

I kind of tied it in with QM, though I could be way off. does the "fuzziness" of space have anything to do with an electron occupying 2 spots in the double slit experiment?

I don't think it does, but i have another question instead. Where does an unobserved electron "go" when it is behaving as a wave?

or ignore this if none of my questions make any sense

Anonymous Wed Feb 16 23:38:37 2011 No.2550021

>>2549983

You're right, but it's the only framework that we can construct that does not yeild a nonsensical solution when combining General Relativity and Quantum Mechanics. Mathematically they are mutually exclusive, except in the framework of strings.

Using strings, the Double Slit Experiment makes sense.

>>	Anonymous Wed Feb 16 23:39:37 2011 No.2550026 what drugs are you on OP?

Anonymous Wed Feb 16 23:42:37 2011 No.2550041

If string theory is correct, then that means there are objects within every facet of reality that require 11 pieces of information to describe specially. It would be like zooming in to a fractal, except it would open into new ways to go at smaller and smaller sizes.... :D

Anonymous Wed Feb 16 23:43:37 2011 No.2550051

If a the moon were suddenly moved very far away from the Earth, would instruments on Earth detect the absence of the moon's gravitational pull instantly after the amount of time it would take a beam of light to travel from the moon's previous location to the Earth?

>>	Anonymous Wed Feb 16 23:45:37 2011 No.2550063 >>2550051 We used to think it was instantaneous, but it travels at the speed of light

>>	Anonymous Wed Feb 16 23:45:37 2011 No.2550064 >>2550051 gravitational waves move at the speed of light

>>	Anonymous Wed Feb 16 23:49:37 2011 No.2550084 Have we found the Higgs yet? And what is being done to search for gravitons? Doesn't the existence of gravitons provide the greatest evidence for String Theory?

Physics Guy Wed Feb 16 23:50:37 2011 No.2550087
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>>2550021

>it's the only framework that we can construct that does not yeild a nonsensical solution when combining General Relativity and Quantum Mechanics. Mathematically they are mutually exclusive, except in the framework of strings.

This is not true. From what facts to you make this assumtpion?

There is a huge difference in saying that:

1) A theory explaining a and b cannot exist

2) Only one theory can exist that explains a and b

3) We are just too stupid (so far) to make a theory that explains a and b

1 and 2, would be extremely hard to prove. They have not been proven yet.

>>	Anonymous Wed Feb 16 23:50:37 2011 No.2550088 >>2550064 is there any way to harness these waves, like ride them like a surfer rides a wave in order to travel the speed of light.

Anonymous Wed Feb 16 23:54:37 2011 No.2550113

>>2550063
Thanks! I thought that was the case but I couldn't remember. Moving masses around seems (on paper) like a way to transmit information. Gravity waves being limited to the speed of light is consistent with "information cannot travel faster than light."

Can you refer me to any experiments that were conducted to arrive at this conclusion? Or maths? I want to know HOW we know this. Thanks again!

Anonymous Wed Feb 16 23:55:37 2011 No.2550116

>>2550064

Gravitational waves move at the speed of light. The speed of light is determined by the values of the electric and magnetic constants (and Maxwell's equations). So gravitational waves move at the same speed as a wave whose speed is determined by electromagnetic constants. Coincidence or deep connection?

Physics Guy Wed Feb 16 23:55:37 2011 No.2550118
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>>2550021
>Using strings, the Double Slit Experiment makes sense.

LMAO, using Quantum electrodynamics (which is the most accurate scientific model even made) the Double slit experiment makes sense.

String theory is not considered science or physics in general. Again, it has no evidence or predictive power, it is just a fancy math, with no known tie to actual reality.

>>	Anonymous Wed Feb 16 23:57:37 2011 No.2550127 >>2550088 That's the idea of warp drive. http://www.popsci.com/military-aviation-space/article/2006-05/warp-drive

Physics Guy Thu Feb 17 00:02:37 2011 No.2550156
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>>2550116
I think you have it backwards.

We say that the speed of light is fundmental, and in fact determines (along with the types of objects makig up the medium) the EM constants.

Think about it for a second, and it will make more sense to you.

>>	Anonymous Thu Feb 17 00:04:37 2011 No.2550162 Does space become discontinuous at smaller than the Planck length?

>>	Anonymous Thu Feb 17 00:04:37 2011 No.2550165 >>2550156 But, you can slow down light slower than electrons. WHERE IS YOUR GOD NOW?!

>>	Anonymous Thu Feb 17 00:05:37 2011 No.2550170 >>2549614 Why u no answer my question

>>	Anonymous Thu Feb 17 00:06:37 2011 No.2550173 >>2550156 Good point. The speed of light is the speed of all things that do not have rest mass.

Anonymous Thu Feb 17 00:11:37 2011 No.2550193

>>2549873
You make the same mistake so many other physicists make. I can have a general state <span class="math">|\Psi> = a |\uparrow>_z + b |\downarrow>_z[/spoiler], which I can express in states of <span class="math">|\uparrow>_x[/spoiler] and <span class="math">|\downarrow>_x[/spoiler] if I choose. While this state may have a well-defined state for trivial values of a and b, this doesn't make them any less real. In fact, this is more real than saying something is in THE z-up state or so forth. Everything I need to know about the electron's spin is in a and b. Just because our measurements are probabilistic doesn't equate it to being unreal. Only measurements are in any way random. The time evolution of any such state is perfectly determined by the current state.

almostphysicist Thu Feb 17 00:13:37 2011 No.2550198

>>2550156
>>2550156
>>2550156
>>2550156
>>2550156

Bullshit. Physics guy is a fraud.

Anyone who's taken electricity and magnetism knows that the speed of light is a consequence of Maxwell's equations and arises (i.e. is derived from, not fundamental) from the permeability and permittivity of free space.

Take it from a REAL physics guy.

>>	Anonymous Thu Feb 17 00:27:37 2011 No.2550209 >>2550198 >the speed of light is a consequence of Maxwell's equations I'm pretty sure the speed of light was already as it is before James was even born.

>>	Anonymous Thu Feb 17 00:31:37 2011 No.2550212 why wont my parakeet eat my diarrhea?

>>	Anonymous Thu Feb 17 00:36:37 2011 No.2550216 File: 20 KB, 300x242, 1233201547341.png [View same] [iqdb] [saucenao] [google] >>2549895 large hardon collider? >mfw methinks OP is a fag

>>	Anonymous Thu Feb 17 00:38:37 2011 No.2550219 >>2550156 Show how you derive the permittivity of free space from einstein's equations or you are a fraud.

>>	Anonymous Thu Feb 17 00:47:37 2011 No.2550235 Horsepower vs Watts, which do you think is a better unit to use?

Anonymous Thu Feb 17 00:51:37 2011 No.2550247

>>2550198

Yes and no. The speed of light shows up places EM waves aren't really part of the question. In civilized units, they're all one, anyways. It's three things, one of which can be defined in terms of the other. Two angles and a side, two sides and an angle, both these define all the quantities of the triangle.

Anonymous of Germany !WvzhzxDiIQ Thu Feb 17 01:10:37 2011 No.2550298

So, electromagnetic waves, group and phase speed can both be faster than the speed of light...

...if so how exactly do I calculate the speed information travels with trough an electromagnetic wave? We kinda skipped over this in class.

Anonymous Thu Feb 17 01:29:37 2011 No.2550365
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>>2550198
>durrrrrrrrr
>hurrrrrrrrr

ε0 and µ0 aren't any more fundamental than c. In fact, if you work in Gaussian units, you can think of c as the fundamental, scale-fixing constant for E&M and ε0 and µ0 are derived from c.

>>	Anonymous Thu Feb 17 01:35:41 2011 No.2550400 >>2550298 This is not correct. EM waves cannot go faster than c. Same with group velocity and phase velocity. Although phase velocity can exceed group velocity, neither can exceed c.

>>	Anonymous Thu Feb 17 01:36:37 2011 No.2550405 >>2550298 This is not correct. EM waves cannot go faster than c. Same with group velocity. Phase velocity is different though. http://en.wikipedia.org/wiki/Phase_velocity

>>	Anonymous Thu Feb 17 01:36:37 2011 No.2550406 >>2550365 sometimes i pull my nutsack through a tiny hole in the crotch of a pair of my jeans and it looks like a piece of chewed gum.

>>	Anonymous Thu Feb 17 01:46:37 2011 No.2550455 File: 237 KB, 608x336, ohmy.png [View same] [iqdb] [saucenao] [google] >>2550406

Physics Guy Thu Feb 17 05:54:37 2011 No.2551535
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>>2550198
Wow, the fucking thread rate on /sci/ has jumped up signfigantly

Anyway, yeah I see what you are trying to say. The problem is you are talking a very narrow approach, you are just using some very very elementary physics (approximations) you learned last term, and assuming that shit is applicable. Try looking at the big picture, and all physics knowledge as a whole.

I can derive all the B shit from, SR and E fields. Likewise then derive all the E shit from QED, stat mech, and particle physics.

In the end c will be the fundmental property, off which I derive my magnegic and electric constants.

>>	Anonymous of Germany !WvzhzxDiIQ Thu Feb 17 06:01:37 2011 No.2551544 >>2550405 Hm.. right. I was confused becuase there were cases in which group velocity was higher than the phase velocity, but that doesn't it mean it can be higher than c now does it. Electromagentism ahoy.

>>	Anonymous Thu Feb 17 06:15:37 2011 No.2551573 >>2551544 I'm pretty sure you were originally right. Both group and phase velocity can be faster than c. To assess the speed of information transfer, though, you need to look at the Green's function.

>>	Anonymous Thu Feb 17 06:34:37 2011 No.2551605 File: 113 KB, 533x800, redchina.jpg [View same] [iqdb] [saucenao] [google] >>2551535 Hey OP. 1) What kind of physicist are you. >>2550015 2) What is "your problem" with entropy. In what sense do you consider it not to be a "fundamental property"

>>	Anonymous Thu Feb 17 06:47:37 2011 No.2551625 File: 60 KB, 319x387, Einstein.jpg [View same] [iqdb] [saucenao] [google] >>2549605 Are alternate universes possible?

>>	Anonymous Thu Feb 17 06:56:37 2011 No.2551645 Astrophysics question concerning the life of stars. When a star of adequate size goes supernova, it has expensed all its hydrogen>helium fusion energy.. stuff..... Where does the helium to birth new stars come from?

>>	Anonymous Thu Feb 17 06:59:37 2011 No.2551655 Meant to ask, where does the hydrogen come from.

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