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Gravity Probe B

Testing Einstein's Universe

Special & General Relativity Questions and Answers

Is the speed of light a barrier of the same kind as the speed of sound?

First, I do not know of any actual instances where a physicist declared that the speed of sound was some kind of 'wall' that could not be overcome. The speed of sound depends on air temperature, density and composition.

The speed of light seems to be, truly, a maximum speed limit that cannot be overcome no matter how you accelerate matter. An enormous number of modern technologies can only operate given that the speed of light behaves as an 'asymptotic limit' to speed. The rate at which particles accelerate for the given applied energy depends critically on the speed of light being a HARD limit to speed.

The behavior of matter is exactly consistent with light speed being a hard barrier, in literally millions of experiments performed every year. Had just ONE of those come out differently, you would see in physics a tremendous amount of excitement. Special relativity has shown not a trace of a flaw in over 70 years of experimentation. Any physicist who detected such a flaw would be as famous as Einstein himself, instantly, over night! If any simple flaw could have been found, it would have turned up already.

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All answers are provided by Dr. Sten Odenwald (Raytheon STX) for the NASA Astronomy Cafe, part of the NASA Education and Public Outreach program.