QUESTION #352
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Does gravity have a speed?

Asked by: Walter Haskins

Answer

If you mean 'does gravity have a speed of propagation?, then the most agreed upon answer is that its speed is c, the speed of light in vacuum, the fastest possible speed.

This can raise surprising thoughts, for example, if somehow the sun were to suddenly disappear, it would take the same amount of time for the light to stop reaching us as it would for our orbit to be destroyed! Intriguing, but to the best of our knowledge, true!
Answered by: Simon Hooks, Physics A-Level Student, Gosport, UK