Einstein Proved Right Again

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Over the years very few experiments have been done to test the predictions of Einstein's theories of relativity.

A key aspect of Einstein's ideas about space and time was the assumption that gravity travelled at the speed of light.  He proposed this thesis way back in 1915 in his general theory of relativity.  This idea was never properly tested experimentally however.  Some scientists continued to claim that gravitational waves could travel faster than the speed of light.

But on one critical night, September 8th 2002, scientists got a chance to measure light from a distant quasar, as Jupiter passed by.  As the wave light came close to Jupiter it was deflected by the giant planet's massive gravitational force, before emerging again and continuing on to earth.  The deflection caused an apparent shift in the position of the light source.  It was similar to when a stick is put into water and seems shorter than it really is.

By measuring the observed deflection, and factoring in Jupiter's known mass and velocity, scientists were able to figure out the speed of the gravitational force that bent the light.  Their conclusion was that gravity does indeed move at the same speed as light.  So, Einstein's instinct about gravity, was again vindicated.

So next time someone says Einstein's ideas were mere theories, tell them experiments are still proving him right.