Is the speed of light truly a universal constant?

[protonman]

(1) How is it that the speed of light is measured the same in all inertial reference frames?

and

(2) For what reason should anyone accept that the speed of light is a universal speed limit.

 

[GRQC]

Originally posted by protonman
(1) How is it that the speed of light is measured the same in all inertial reference frames?

and

(2) For what reason should anyone accept that the speed of light is a universal speed limit.

Both of these questions are currently being discussed in other threads. You should look around the site for those (I think they're in "Theory Development" or "General Physics").

 

[HallsofIvy]

Originally posted by protonman
(1) How is it that the speed of light is measured the same in all inertial reference frames?

and

(2) For what reason should anyone accept that the speed of light is a universal speed limit.

Same reason that would be given for questions on any physics point:
"That's what the experimental evidence says". Arguments about "reasonableness" cannot stand in the face of experimental evidence. (And the experimental evidence in favor of relativity is overwhelming.)

 

[Deeviant]

Lets get back on track with protonman's first questions.

Originally posted by protonman
(1) How is it that the speed of light is measured the same in all inertial reference frames?

and

(2) For what reason should anyone accept that the speed of light is a universal speed limit.

1. Because experiment and observation have relentlessly agreed with the invariance of the speed of light.

I'm not sure what your actual motivation of asking this question but if you are trying to disprove SR, then I suggest you provide some reliable data that suggests to the fact. If you don't like using experimental data or any sort of observation I would very much like to know just what exactely you would like to base your theory on.

2. Once again one possible reason one would believe information follows C as universal speed limit is because experiments and observation have once again shown it to be true.


If you have some other mechanism other than observation and experimentation that produces correct answers, please, enlighten us.

 

[David]

Originally posted by Deeviant


1. Because experiment and observation have relentlessly agreed with the invariance of the speed of light.

This is not true. The Shapiro tests in the 1960s showed that radar waves bounced off of Venus slowed down as they passed near the sun. General Relativity has light speed slowing down in a gravity field. This is a well-known fact of science.

 

[Peterdevis]

Dear David,

I' m happy you are back. Now you back on the forum I 'm sure that you will reply on my post of 02-28-2004 (about different sorts of time).

We don’t want to come here and say something, and then have 6 arrogant know-it-all moderators jump on us and attack us.

Take your oppurtunity to "attack" me (I'm not a moderator, so I can't block you) and proof that I'm wrong and you 're right.

 

[Janus]

As the bulk of this thread has no connection to the actual heading of this forum I have split it off to Here:
https://www.physicsforums.com/showthread.php?threadid=15790

I also edited out the "extracurricular activity" .

I left the post's directly pertaining to the initial questions here. However, since this topic has been covered very completely in other threads, I suggest it be continued there, and I am locking this particular thread.