Skip navigation

Gravity Probe B

Testing Einstein's Universe

Special & General Relativity Questions and Answers

If there is so little friction in space, why can't we reach the speed of light with a big rocket?

Because this limitation is built-into space-time itself, which is a property of the gravitational field of the universe. Nature seems to be locked-in to this velocity limit, and there is nothing that we can do to the matter and energy within space-time that can exceed this limit. We can no more exceed the speed of light than we can alter any of the other constants in Nature.

Return to the Special & General Relativity Questions and Answers page.

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