Speed of Light and Theory of Relativity ?

[Spyman]

Well, 200 years ago, passing the speed of sound seemed impossible. I believe that passing the speed of light is atainable with out question. If not, then the human race is screwed.

With our current technology and understanding of the universe it is impossible, and I belive the human race will do just fine even if we never find a way to beat lightspeed.

[swansont]

swansont and Meir Achuz seems to belive differently, or am I just misinterpreting their posts ?

 

Misinterpreting. Measuring two photons going at c in opposite directions is not the same as measuring one photon's speed relative to the other.

[Spyman]

Measuring two photons going at c in opposite directions is not the same as measuring one photon's speed relative to the other.

Thats the kind of answer I would have liked to have had in the beginning.

[swansont]

Thats the kind of answer I would have liked to have had in the beginning.

 

Your setup does not measure the relative speed of one photon to the other. It measures the speed of two separate photons by some observer. To measure the speed of one photon to the other, you'd have to be in one of the photon's frames of reference, which you can't do.

 

was post #2. i.e. the very first reply.

[Spyman]

was post #2. i.e. the very first reply.

Yes, You are correct and I apologize.

I just didn't understand Your post back then, just seemed cryptically to me, guess I am a slow learner.

Repeat, repeat and repeat...eventually I will grasp it.

 

 

From this perspective the photons can be considered to be 2c in relative velocity. This does not violate the "c" speed limit. Similarly 2 masses can approach 2c relative velocity as you have described' date=' [b']from the third party perspective.[/b] (although it's not usually viewed that way)

 

From either of their own it would still be less than c.

In your reference frame 2 photons sent in opposite directions will "distance" themselves at a rate of 2c. This does not contradict relativistic velocity addition. Nothing is exceeding c in any inertial frame.

I just realized I never said thanks to J.C.MacSwell, who was the one answering my question in a way I actually could understand.

 

Thanks ! :-)

[[Tycho?]]

Well, 200 years ago, passing the speed of sound seemed impossible. I believe that passing the speed of light is atainable with out question. If not, then the human race is screwed.

 

There were no theoretical restrictions on passing the speed of sound.

[Saint]

'']There were no theoretical restrictions on passing the speed of sound.

Theoretically, yes there were. If you view the drag profile of a body moving toward the speed of sound, it's asymptotic. At the sound barrier it takes a steep dive. But I don't believe that was known until it was tested. There was, theoretically, sceintific data (calculations) to support the idea that the speed of sound was the physical drag limit.