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Gravity Probe B

Testing Einstein's Universe

Special & General Relativity Questions and Answers

Is there a static condition against which the speed of light is measured?

There is none. All velocity measurements are relative to whatever you choose as your local standard of rest. That's the wonder and mystery of relativity!


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.