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-   -   Theory of Relativity? (http://www.physicsforums.com/showthread.php?t=441210)

.euphoria Oct24-10 02:16 PM

Theory of Relativity?
 
Okay, now I know something like this may seem improbable.
But what would happen if Einstein's theory of E=mc2 was wrong?

Fredrik Oct24-10 02:33 PM

Re: Theory of Relativity?
 
Theories aren't classified as "right" or "wrong". They're all wrong, but some are less wrong than others, in the sense that they make better predictions about results of experiments. We already know that this particular theory makes fantastically accurate predictions, so I don't see how to make sense of the question.

.euphoria Oct24-10 11:08 PM

Re: Theory of Relativity?
 
Okay, Lets say we could accelerate towards c without our mass becoming infinite. Would this have implications on the lawsof physics as we know it?

FunkyDwarf Oct24-10 11:12 PM

Re: Theory of Relativity?
 
Yes, **** would break, badly.

Pengwuino Oct24-10 11:15 PM

Re: Theory of Relativity?
 
Quote:

Quote by .euphoria (Post 2950938)
Okay, Lets say we could accelerate towards c without our mass becoming infinite. Would this have implications on the laws of physics as we know it?

To be more accurate, you would want to talk about accelerating beyond c such that the energy wouldn't have to become infinite. If you were able to smoothly cross the barrier from slower than the speed of light to greater, it would be pretty bad. One problem is that you can derive the implications of special relativity using such unbelievably basic starting points, violating it would mean those basic ideas are wrong. The homogeneity and isotropy of space-time would be out the window or require modifications.... but if there were such things as preferred directions, what does that mean?

.euphoria Oct24-10 11:25 PM

Re: Theory of Relativity?
 
So basically, Pretty much everything we know about the laws of physics would be compromised and have to be re-thought?

Also one question still remains, What would happen to the concept of time if one could pass light speed? Would time dilation still happen at speeds greater than c or is it limited to below light speeds?

Fredrik Oct25-10 04:12 AM

Re: Theory of Relativity?
 
Quote:

Quote by .euphoria (Post 2950090)
But what would happen if Einstein's theory of E=mc2 was wrong?

This is like asking what would happen if we discover that we've been wrong all this time to think that stuff we drop fall towards the ground, and that they actually just float at a constant distance from the ground.

Quote:

Quote by .euphoria (Post 2950938)
Okay, Lets say we could accelerate towards c without our mass becoming infinite. Would this have implications on the lawsof physics as we know it?

OK, it makes sense to ask what would it would mean if special relativity makes bad predictions about massive objects that have been accelerated to speeds extremely close to c. It would mean that both special and general relativity would have to be replaced by more accurate theories (but we already know that they need to be replaced, because SR can't handle gravity and GR can't handle quantum effects).


Quote:

Quote by .euphoria (Post 2950963)
What would happen to the concept of time if one could pass light speed? Would time dilation still happen at speeds greater than c or is it limited to below light speeds?

If relativity didn't say what it says, it wouldn't be relativity, would it? Are you asking us to use another theory to answer the question? Which theory would you like us to use?

pallidin Oct25-10 05:12 AM

Re: Theory of Relativity?
 
That the speed of light is some immutable barrier seems intuitively ridiculous.
c is very SLOW.

I think that the potential of "instantaneous" should be considered as a viable concept.

"Frame-dragging" anyone? c changes in that warped space-time local environment.

arkajad Oct25-10 05:36 AM

Re: Theory of Relativity?
 
Quote:

Quote by .euphoria (Post 2950090)
But what would happen if Einstein's theory of E=mc2 was wrong?

But is it true? For photons, for instance, m=0, but E>0.

Hyperspace2 Oct25-10 06:19 AM

Re: Theory of Relativity?
 
Quote:

Quote by arkajad (Post 2951351)
But is it true? For photons, for instance, m=0, but E>0.

energy of light is due to its frequency
E= h*f

E= h*c/L
h=plancks constant, c=speed of light
f = frequency = c/L, L=wavelength
E= h*(C/L)
Equating it to eeinsteins mass
mc^2= h*(c/L)
m= h/(c*L)
Hence it is like apparent mass. Yes photon has mass and it depends upon wavelength.

arkajad Oct25-10 06:32 AM

Re: Theory of Relativity?
 
Quote:

Quote by Hyperspace2 (Post 2951390)
Yes photon has mass and it depends upon wavelength.

A mass moving with the velocity of light?

ZapperZ Oct25-10 07:39 AM

Re: Theory of Relativity?
 
OK, let's not change this thread into issues about photon mass. This has been sufficiently addressed in many threads, and in our FAQ in the General Physics forum (read it!). So cease this line of discussion right now.

Zz.

arkajad Oct25-10 08:26 AM

Re: Theory of Relativity?
 
Wasn't E=mc^2 sufficiently addressed in many threads?

ZapperZ Oct25-10 08:31 AM

Re: Theory of Relativity?
 
Quote:

Quote by arkajad (Post 2951526)
Wasn't E=mc^2 sufficiently addressed in many threads?

Yes, but at least, that is relevant to the OP's question. Discussing about photon mass isn't, especially when it is getting into the validity of the idea of "relativistic" mass. Read the OP's question again.

And taking about the OP's question, I think this thread is rather moot. We can do an infinite amount of speculation on what if such-and-such is wrong. I see very little informational or educational value out of something like this. I can see research-front scientists asking such questions due to plausible reasons, but I don't see how someone who are just looking into such a thing would gain anything of any value.

Zz.

arkajad Oct25-10 08:37 AM

Re: Theory of Relativity?
 
I agree, but I thought wouldn't it be better to replace the potentially misleading, unless taken in a proper context, E=mc^2 formula with a rigorous and clear

http://upload.wikimedia.org/math/f/6...29813279d0.png

ZapperZ Oct25-10 08:45 AM

Re: Theory of Relativity?
 
Quote:

Quote by arkajad (Post 2951544)
I agree, but I thought wouldn't it be better to replace the potentially misleading, unless taken in a proper context, E=mc^2 formula with a rigorous and clear

http://upload.wikimedia.org/math/f/6...29813279d0.png

Don't confuse what the OP asked with the mistake that Hyperspace2 made. We don't know yet if the OP either knows about the full equation, or if the question is really specific that to the mass-energy relation. Often, threads like this are made worse by responses that assume way too much and cover too broad of an area.

Zz.

arkajad Oct25-10 08:56 AM

Re: Theory of Relativity?
 
Quote:

Quote by ZapperZ (Post 2951555)
Often, threads like this are made worse by responses that assume way too much and cover too broad of an area.

Zz.

Often they get worse, but sometimes they get better. If we do not know what the OP knows, why not to point him out in a good direction? It will not make any harm, will it?

Hyperspace2 Oct25-10 10:42 AM

Re: Theory of Relativity?
 
Quote:

Quote by arkajad (Post 2951400)
A mass moving with the velocity of light?

Evidences

eeinstein says mass and energy are equivalent.
Light is deflected by gravity. etc etc


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