# A 30 year test of General Relativity

1. Jul 7, 2004

### marcus

At this and other PF forums people have several times been referring to the very precise test of General Relativity being made with this
binary pulsar

thirty years of testing the prediction of GR are summarized in this
paper

http://arxiv.org/abs/astro-ph/0407149
Relativistic Binary Pulsar B1913+16: Thirty Years of Observations and Analysis
J.M. Weisberg, J.H. Taylor

it is like having two very accurate clocks orbiting each other
there are two neutron stars, each of them a pulsar,
in close fast orbit around each other

Any pair of objects in a binary orbit must stir up ripples in the graviational field as they go around each other---and must radiate away energy
but only if they are close and fast and massive will the radiation amount to much
these two neutron stars radiate away energy (GR predicts) fast enough that they gradually come closer and closer to each other, spiralling in, go noticeably faster

over 30 years the change has been measured and the rate of energy loss agrees to within observational error (to within 0.02 percent) with what the theory of gravity predicts.

BTW some other binary pulsar pairs have been found---I remember posting about one of the finds not so long ago. These pairs of neutron stars are very nice objects. The pair actually loses mass as it radiates gravitationally.