/sci/ - Science & Math

jelly?

Light always travels the same speed no matter your speed relative to it, fag.

>>2936797

Relativity states that the speed of light will always be MEASURED at c, Faggot.

Relatively speaking, of course...

-Edrick

>>2936772

First frame "Your local time slows down.." is bullshit.

Next.

>>2936822

You never heard of time dilation?
http://en.wikipedia.org/wiki/Time_dilation

-Edrick

>>2936790
lrn2 relativity

>>2936842

Yes. And it does not say that time slows down.

lrn2relativity and then post some actually good troll science comics.

>>2936862

lrn2 Ehrenfest theorem.

>>2936772
Ha ha, he thinks that he can add velocity vectors like in Newtonian physics.
Go read a book about special relativity, then come back.

/sci/ is the smartest board, but has the worst troll detection ever.

Look at the signs: troll physics, an absurd name (physics god? trolololol), a signature with his (assumed) real name.

>>2936886
http://www.youtube.com/watch?v=AZ6N85lNgHY

You sure?

-Edrick

>>2936929

Yes, i sure.

Time dilation says an observer would say to a moving troll "Hey you, it seems your time passes by slower relative to mine" to which the troll respondes "No way, your time passes by slower than mine it seems".

Both perceive, for themselves, the same rate of time passing by for them. There is no reason at all for why that would change.

lrn2relativity

>>2936929

lol so you think you'd actually slow down if you were in a space ship?

>>>/x/ is that way

>>2936949
Sir, I kindly ask that you avoid feeding the trolls. They get unruly.

>>2936954

I concur. Excuse my faggotry and lack of troll detectory and thanks for your kind advice.

May thy fare well.

>>2936949

And what of a beam of light passing you by, if you are moving at 99%c?

Why would you see it moving at the speed of light relative to you, instead of at 1%c?

-Edrick

>>2936889
What for? Are you retarded? It's a classical problem. Inertia would destroy any material.

>>2936987

Because experiments told us so.

No, it's not the theory that gives that conclusion.

>>2936987
Light moves at c for all reference frames, that's how.

>>2937016
I ask you "Why" and you answer with "It just does!"

TROLOLOL, You try to answer relativity question, when you don't understand relativity.

>>2937017
Pic is for you.

"If you can't explain it simply, you don't understand it well enough"
-Einstein

-Edrick

>>2937067

lrn2relativity

The speed of light being constant MUST be postulated in order to deduce the theory. Get out of here, it's the wrong board for you.

It is NOT something you get out of the theory.

It works this way:

Light speed is constant -> Lorentz-symmetry -> lenght contraction/time dilation

NOT

anything -> speed of light is constant

Idiot.

Speeds higher than c make Lorentz factor turn into a complex number and everything is broken.

>>2937081
>"lenght contraction/time dilation"

You see my OP pic then? in the third frame?

And I suppose if the light was moving in the opposite direction from you, instead of the same direction, you would be streched out and time-speeded-up?

XD

-Edrick

>>2937067

> I ask you "Why" and you answer with "It just does!"

Yeah, because that's the correct answer, troll.

http://en.wikipedia.org/wiki/Speed_of_light#Fundamental_role_in_physics

>>2937101

As someone already said, time does not actually slow down. Especially not "locally".

Whatever, i´ll leave this thread now and leave knowing you are staying uneducated for the rest of your life. Makes me a bit sad, but then again, i shouldn't care.

>>2937101

movign relative to WHAT? Idiot, that's the fucking point.

"Einstein"
"Relativity"
"Time Dilation"
"It Just Does"

Try not to think about it too hard, eh?

-Edrick

>>2937125
You ask that question, as if it matters!

>>2937150

-Edrick

>>2937067
>I ask you "Why" and you answer with "It just does!"

That's because that is the correct answer.

Also, sage. Either troll or retard who thinks he's being smart. Either way, sage.

Don't Question Einstein! Science can't bear the SCRUTINY!!!!

TROLOLOL!

-Edrick

>>2937173

You travel at 99%c away from earth.

A photon passes you in your direction of motion, and another passes in the opposite direction at the same time.

If length contraction and time dilation is why we see the photon overtaking us as going c, then what about the photon that is going the opposite direction?

Are we also stretched and time-accelerated at the same... "Time"?

LOL!

-Edrick

>>2937177
We'll let you know when you actually approach something that questions Einsteins Relativity. You aint thurr yet

>>2937211
Oh please... you guys can't even think for yourself enough to take in a simple thought experiment without automatically having the "But Einstein was a GOD" knee-jerk reaction.

Fucking-FAIL-Fags.... Relativity is flawed, asshats.

-Edrick

>>2937231
Alright, you're right. Relativity is flawed.

Please write a scientific paper and submit it to peer review so that our knowledge of physics can advance.


....oh wait, you're a fucking retard. Your paper won't pass peer review because you don't understand high school physics.

>>2937240

I have to ask... what high school did you go to where they taught Special relativity?

Also, TROLOLOLOL!

-Edrick

>>2937205
There is neither length contraction or time dilation in your own frame. Both photons go at speed c, one is red shifted the other is blue shifted. These are all effects of Lorentz invariant frames.

>>2937231
I actually havent taken that stance, and I dont consider him or his theories infallible. Nevertheless, you dont understand the Special Theory of Relativity, and until you do you cant start poking holes in it

>>2937250
GTI Gymnasium in Gothenburg, Sweden.

>>2937253
Speed is distance over time.

If I am traveling at 99%c, and I see something passing by me at 100%c (relative to stationary earth), then I SHOULD only see it going at 1%c relative to me.... however, relativity states that this is not the case, because to an outside observer, I am time dilated, and "Squished" so that my reference frame (for distance and time) is skewed so that I "See" the photon pass by me *AT* 100%c.

Now, this would indicate that to MY perspective, I see the universe as "Sped Up" and also "Lengthened" along my axis of travel relative to the stationary Earth.

So, what of a photon that is moving in the opposite direction?

Would not that appear to be also lengthened and sped up so that I see it moving at 100%c+ ?

-Edrick (I'm serious by the way, and no-one has ever answered this question simply, instead getting all butthurt about it, as if Relativity were a religion, instead of a science that must be questioned.... Be scientists, Damn your Eyes...)

>>2937291
You were acting like a massive moron about it before.
The coolface images certainly didn't help either.

What you are doing wrong is that you assume that because of time dilation and length contraction you measure the photon's speed to be c.

This is not the case. Light ALWAYS travels at c, regardless of one's inertial reference frame. As my physics teacher put it "In order to understand relativity, you HAVE to accept this, even if it doesn't make sense. Now shut up and calculate!"

>>2937314
>"In order to understand relativity, you HAVE to accept this
>even if it doesn't make sense. Now shut up and calculate!"

I was taught that Science accepts nothing without evidence, and in the absence of being dis-proven.

Now, without resorting to "Because that's how our beautiful mathematics WORK", explain WHY this is the case?

I'm dead serious... WHY do we see light as always being at c despite our frame of reference?

If it's not that our frame of time reference slows down, that would indicate that we are changing the definition of speed.

This sounds more like religion than science, actually.

I WOULD like to ask these questions to someone who is qualified to answer them, a Physics professor, perhaps, and if I could *FIND* such a place to ask my questions, then I would of course, happily leave /sci/ to it's own devices, without my "Pseudo-trolling"

-Edrick

>>2937291
>Would not that appear to be also lengthened and sped up so that I see it moving at 100%c+ ?
I dont really get what you are asking here. Are you asking if the photo would appear "lengthed and sped up"? No, they both move at c. If they had the same energy in a stationary frame, the one moving in your direction would have lower energy and the one in the opposite direction would have higher. This is essentially the analog of time dilation/length contraction for massless (speed of light bodies)

>>2937351
What I am asking, is *WHY* does light always appear to move at c regardless of your frame of reference?

There *MUST* be an answer to this question.

If I am traveling at 50% c in the same direction as a photon, then I should only see that photon moving at 50%c relative to me.

This is classical, Newtonian physics...

What I am asking, is WHY do I instead see this photon moving at 100%c relative to me?

-Edrick

>>2937337
I dont know how qualified i am, but I spent a few years doing physics grad work. I dont think you are going to find an answer to your question beyond what i said in >>2937351
You will be disappointed to find out physics rarely answers questions like "why is something this way" But the only other thing i can say is that a locally constant speed of light is need for causality to be valid, and as far as we can tell we live in a casual universe. To ask why beyond that approaches religion/philosophy at this point

>>2937381
that should have been "we live in a causal universe" heh

>>2937337
We have conducted many experiments that validate the statement that light travels at c regardless of one's inertial reference frame.

Check out the Michelson-Morley experiment.

>>2937410
Yep. My specialty in grad school was astroparticle, and there are plenty of instances where massive particles reach speeds nearing c. If causality was violated it would be pretty obvious.

Ok, let me put this a different way....

Speed is a unit of measure of distance traveled over a unit of time.

And relative speeds are the same thing, except the distance (meter stick, maybe) is in motion relative to a stationary observer.

If I have a meter stick, and I am traveling at 50%c and a photon crosses that mater stick parallel to my direction of motion, a stationary observer would see the photon crossing my meter stick in 1/600,000,000 of a second (indicating a relative speed of 50%c), instead of 1/300,000,000th of a second.

I however see the photon crossing my meter stick in 1/300,000,000th of a second, indicating it's speed is exactly c.

What about my frame of reference has changed to make the photon go faster (according to my reference frame) than it "Should"?

-Edrick

>>2937481
Okay, messed that up, change 1/600,000,000th to 1/150,000,000th

-Edrick

The constancy of c was known far back by people like maxwell, it is in fact in one of his equations for electromagnetism.

The price we had to pay to keep c constant in EVERY reference frame was the conversion of matter into energy and the anihilation of newtonian physics

>>2937481
Well I'm no expert, but...

Time dilation, time is moving slower for you and this changes the apparent speed rather than the apparent distance.

This is space time, not just a 3d static space you're working with.

So, what you guys are saying is... that you have absolutely no IDEA, *WHY* this is true?

You don't know WHY any of these "Relative Speed" changes take place, or even IF this is true, except for appeals to authority?

Oh, and by the way, I read the Michelson-Morley experiment, and it's results were.... somewhat inconclusive, actually.

-Edrick

>>2937531
see
>>2937450

Your frame of reference has rotated!

>>2937531
To be fair, you're not speaking to physics professors or even physics students here.

>>2937481
At this point all i can say is, no it doesnt. Galilean transformations dont work at speeds in excess of c. why? 1)they just dont, which i know you dont want to hear but there is empirical
evidence telling us its true 2) if your view was true causality would be violated constantly
Again, in your example, the stationary obeserver sees a different energy photo moving at c

>>2937523
If time is moving slower for me in order to make sure the photon moving in the same direction as me stays safely at c, then why is a photon that is moving in the opposite direction from me ALSO moving at c?

If my time-frame is slowed down, and i'm still moving at 50%c, and a photon is moving in the opposite direction.... then according to Newtonian physics, I *SHOULD* see that photon moving at 150%c relative to me...

But since my time is slowed by 50% to make the photon moving in the same direction to me be moving "relatively" at 100%c, then that means that the photon moving in the opposite direction SHOULD be observed moving at 200%c

But, apparently, My time-frame is ALSO sped up at the same time it is slowed down, so that the photon moving in the same direction as me is observed moving at 100%c, and ALSO the photon moving in the opposite direction from me is moving at 100%c.


So, which is it?

Is my time-frame sped up, or slowed down?

-Edrick

>>2937560
Actually i said i was a physics grad student, i have a BS in physics as well. I taught relativity as a grad student, granted its been a few years and im very rusty

>>2937568
>then why is a photon that is moving in the opposite direction from me ALSO moving at c?

See
>>2937450
t + x/c and t - x/c are stretched/shrunk. Neither part of the transformation changes the speed of light in either direction.

>>2937567
>if your view was true causality would be violated constantly

From what I can tell, so far, Relativity Violates causality all the time anyways.

-Edrick

>>2937583
>t + x/c and t - x/c are stretched/shrunk. Neither part of
>the transformation changes the speed of light in either direction.

I'm talking about the relative speed of light, not the actual speed of light.

-Edrick

>>2937568
I think i might see the point of confusion. To be clear, a STATIONARY observer will consider YOU to be length contracted and have a slower running clock. Photons have no stationary frame, you measure things normally in your own frame, and the difference between your frame and say, earths is that you measure different energies for the photons. But they still travel at c.

>>2937584
No, it doesnt. If you think so, please give an example.
At this point I just dont think you want to hear the answer, you are so set in thinking you understand what is going on. I applaud your intentions, though, Questioning is good

>>2937595
but they are the same thing =/

>>2937595
There is no difference between those concepts. The relative speed of light is the actual speed of light in a particular rest frame.

If by "relative speed of light" you actually mean the difference in velocities between some object and some light (which is called "closing velocity"), that obviously isn't always c.

>>2937595

There is only one speed of light, all the experiments made so far have measured the same value

I have a buddy, astrophysics major, who is going to hate you all when I end up asking him naive questions later.

This stuff makes me rage a little when I don't understand it because of how ridiculously unintuitive it is. I rage even more when I put my mind to it, study it, and finally seem to grasp it, only to realize that there's no answer as to WHY something works the way it does.

It's like imagining myself being an ignorant hunter-gatherer, looking at the sea, wondering why the tide goes in and out, and railing against the unfairness that, no matter how hard I try, I'll never get an answer as to why it does. I can make up stories, develop ideas, but I'll never have a way to figure it out.

Not knowing is one thing; there's a pleasure in a mystery and being able to find out an answer. Not being able to know or find out just upsets me.

>>2937593
Ok, Speed is merely an abstract concept of a distance traveled, over a unit time.

If I am moving at 50%c, and measuring a photons speed that is moving past me... then technically, I have actually INCREASED the distance that I am measuring the speed of the photon FROM.

So, by definition, I would *HAVE TO* see the photon moving slower than c relative to me, because the distance has technically changed.

So, unless the photon has increased in speed, my measuring stick has shrunk, or my time-frame has slowed, I WILL MEASURE IT'S SPEED at 50%c

So, which is it?

Am I shortened relative to my direction of motion?

If that is the case, the photon moving in the opposite direction will be observed traveling a larger distance over the same amount of time, and thus, moving faster than c.

Is my timeframe slowed down?

If that is the case, I will see the photon moving in the opposite direction as having covered the distance in half the time, and thus, moving faster than c.

OR, has the photon sped up, or slowed down?

In which case, the entire argument is null and void.


Speed is a measure of distance over time.

Speed = Distance * time.

One of these things MUST change to conserve c in all reference frames, otherwise MATH ITSELF is broken.

-Edrick

>>2937619
Special relativity is one of those things that is ESPECIALLY unintuitive, very hard to teach, and much like quantum mechanics you really have to just
"shut up and calculate:" for a while before you get it.

>>2937632
That's because it's not science... it's religion.

-Edrick

Man, just believe it, c is the same for all observers

>'they dont think it be like this, but it do'

>>2937629
Or, relativity, especially when involving photons, doesnt fit into your logic.
And to be fair, speed=dx/dt says nothing about the frame you are in

>>2937649
Lol k, im done. I tried my hardest. Let me know when stephan hawking agrees with you and you two write an awesome science paper.

You are thinking with coordinates (x,y,z)

You have to think with (x,y,z,t)

one other thing i forget to mention is the wavelength (and hence the energy) of the photo changes when you move relative to it, perhaps that will help you get your head around the measure issue. So when its moving away from you the wavecrests are more spread out than the one approaching you.

>>2937629
As usual, you're forgetting about relativity of simultaneity.

>>2937659
Ok, look, this is not that complicated a thing to understand...

I'm on a rocket moving away from earth at 50%c, and a photon moves past me.

From the earth, they see the photon moving past me at 50%c faster than I am moving, and thus, deduced from Earths stationary position, the photon is moving at 50%c relative to me.

However, I see the photon moving at 100%c past me, as If I was not even moving.

This implies that either my time-frame has slowed down, my measurement has shrunk, or the photon is moving faster.

Or, all three.... lol

Think about it, without running back to your mathematics and appeals to authority...

I'm SERIOUS, THINK about it.

Don't just say that it's true... Damnit, 4chan... /sci/... use your brains!

EXPLAIN THIS SHIT!

-Edrick

>>2937699
You're used to simple newtonian relations holding true. The fact is, they don't close to the speed of light. Your assumptions break down.

It's like trying to explain chemistry with the plum pudding atom model.

>>2937723

Then do YOU understand it?

If So, Can YOU answer my question?

Can You? Do You?

-Edrick

>Think about it, without running back to your mathematics

but you fucking need math to derive the equations, Einstein had to this himself!

Do you know calculus, linear algebra?

A Brief History of Relativity

Once upon a time there was this guy called Einstein. He read about Maxwell's equations, from which it was calculated, that light is an electromagnetic wave (which was later shown in many experiments). There was just one problem: from those equations people calculated, that <span class="math">c=\frac{1}{\sqrt{\epsilon_0 \mu_0}}[/spoiler], where <span class="math">\epsilon_0[/spoiler] and <span class="math">\mu_0[/spoiler] are important PHYSICAL CONSTANTS. "Shit" - though Einstein - "this is denying Galileo transformation, making speed of light constant for every observer. We have to this about better transformation". And that transformation was Lorentz transformation in Minkowsky's spacetime. "Get the fuck out, Einstein" - said other physicists - "this can't be right". But then they make observations. Lots of them. Conclusion: "shit, he was right". The End.
And WHY it's true? We don't know. Just like Newton couldn't say, why the fuck gravity works and we had to wait 200 years, when Einstein came up with idea, that it's bending spacetime. Does that mean that "hurr durr, gratovee doesnt werk, Newton couldn't say why it is werking, so it must me wrong, herpy derpy durp". First you're observing something, and then you try (the keyword being 'try') explain, why this shit works. Wait another 10, 20, 50 or 100 years, maybe somebody will be able to explain this.

>Physics GOD!
>questions Relativity
>galilean kinematics

10/10

>>2937737
The math explains what happens. Einstein's postulates are the "why" and the basis for the math. Why do we accept? Scientific evidence.

>>2937752
I'm going to explain this to you, using small words so that you will all understand.

Time is not a dimension.

It never was.

Plotting time on a dimensional graph as if it was a integral part of reality is absurd, and is WHY you can't answer my question, because your science is making assumptions about the nature of reality, that while work in a tiny, mathematical sense, isn't actually True.

Time, is an abstraction of motion. that is all that it is.

How long it takes for the earth to revolve around the sun, around its axis, how long it takes an electron to circle the nucleus of an atom.

All of your mathematics are DESIGNED, not to find out how reality works, but to find new ways to prove "Relativity" correct.

And THIS is why you can't answer my VERY simple question.

Why do I see a photon traveling beside me, as ALWAYS moving at 100%c relative to me, unless distance or time changes?

And IF they change, do they change depending on what direction the photon is traveling from?

Do not sketch your world-line bullshit, it's meaningless pseudoscience if you cannot answer this simple question.

-Edrick

>>2937809
>Why do I see a photon traveling beside me, as ALWAYS moving at 100%c relative to me, unless distance or time changes?

Because that is a fundamental hypothesis.

Einstein did the math, and said ok, if this hypothesis is true, here's what will happen. It is easily something that COULD have been wrong. But evidence supports it.

You are mixing up pseudosciencephilosophy with

hypothesis, prediction, confirmation of the scientific method

I am arguing against Relativity, with people who are DEFENDING relativity, despite the FACT that they do not UNDERSTAND relativity, but defend it anyways.

And herein lies the most important question:

Why are you presuming to defend something that you do not understand?

-Edrick

>>2937809
>Plotting time on a dimensional graph as if it was a integral part of reality is absurd,

>>2937809

> Time is not a dimension.
> It never was.
Oh yes it is. At least that is its behaviour.

> Plotting time on a dimensional graph as if it was a integral part of reality is absurd
That's why we can't plot function x(t), where x is for example coordinate of harmonic oscillator in particular moment in time. Oh wait, we can.

> How long it takes for the earth to revolve around the sun
From which point of view? Ours? Around 365.25 days.

> around its axis
Slightly less that 24 h (they don't teach this shit at school?)

> how long it takes an electron to circle the nucleus of an atom
Electrons don't circles around nucleus, that's an old Bohr model, nothing to do with reality. We can only say what is the probability of finding an electron in some point in space (not only in its orbital)

> All of your mathematics are DESIGNED
Correct. You know how we're "designing" math? TO PROPERLY DESCRIBE OBSERVED REALITY. You get empirical data, you make a model and you test it. If it passes many different tests, them you have a pretty good theory.

> And THIS is why you can't answer my VERY simple question.
Oh, we can. And we did. You're just rejecting this answer. That's why you're no better than young Earth creationists. And that's why you're a dumbass.

>>2937876
Hate to break it to you, but you're the one who doesn't understand it. Hence why you keep trying to disprove it with classical mechanics.

>>2937881
And if time is an integral part of reality, then why does it dilate?

Retard.

>>2937882

I'm not arguing the practical mathematical application of your dimensional analysis with mathematics, I am arguing against its inherent validity.

>Electrons don't circles around nucleus, that's an old Bohr model
>nothing to do with reality. We can only say what is the probability
>of finding an electron in some point in space (not only in its orbital)

Electrons are not real, it's all waves. XD

Which is why there is only a probability of finding it in a certain place, because where *IS* a wave, exactly?

>Oh, we can. And we did. You're just rejecting this answer.
>That's why you're no better than young Earth creationists.
>And that's why you're a dumbass.

No, this is the problem, you are *NOT* explaining, OR answering my question, you are drawing stick figures to further impress the complexity of the issue instead of actually answering the question.

Let me ask this again:

If I am moving at 50%c relative to earth, and a photon passes me, why do I see it as moving 100%c relative to me?

Does that mean that the photon is moving at 150%c relative to the earth?

-Edrick (Think God Damnit, THINK! I'm not retarded, I'm not trolling, I'm just trying to understand this shit, and you are trying to explain it, without actually understanding it yourself!)

>>2937364
>This is classical, Newtonian physics...

So are you doing the same thing you accuse /sci/ of?
Only instead of Einstein, your religion is that of Newton? (assuming both have observations that validate them to go on).

>>2937918
If height is an integral part of reality, then why does it change when I lie down?

You are retarded because you have been given the answer, and refuse to accept it because it was in graphical form, because apparently we can't graph time.

>>2937337
Generally universities are supposed to be good for that sort of thing. You don't always have to be a student to attend lectures (and get a chance to speak at some point) either.

> Electrons are not real, it's all waves. XD
Actually it's neither wave, nor corpuscular. It's something behaving sometimes more like the first one, sometimes more like a second (depending on the environment).

> you are trying to explain it, without actually understanding it yourself!
> me: 2nd year physics student
> <- mfw

Ok, let approach this from a different way.
Why does Newtonian mechanics work in everyday life?

jfc this is still going? OP, i honestly thought maybe you werent trollin, but you are, whether or not you realize it. You dont know shit about math, special relativity or quantum mechanics. The more you condescend those who do, the less likely they are to help you.

oh and
>And if time is an integral part of reality, then why does it dilate?
>Retard.

Because its really spacetime that is the integral part of reality, and its spacetime invariance that causes dilation/contraction. In short, space turns into time and vice versa depending on frames.

>>2937978
It's a classic case of ignorance + arrogance. OP unfortunately isn't alone:

http://users.telenet.be/vdmoortel/dirk/Physics/ImmortalFumbles.html