<i>Einstein's theory of general relativity holds up</i>
Einstein's theory of general relativity holds up, according to astrophysicists who tested it against a unique cosmological configuration of two pulsars orbiting each other.
Pulsars are small and extremely dense stellar objects left behind after massive stars explode.
They spin at staggering speeds, generating huge gravity fields and emitting strong beams of radio waves from their magnetic poles -- much as lighthouses emit beams of light -- which can be picked up by radio-telescopes on Earth.
Scientists know of more than 1,700 pulsars in our galaxy but of only one binary-pulsar system, discovered in 2003. It comprises two pulsars locked into close orbit around each other, so close they could fit within the Sun.
Because of its strong gravitational field, this system is the best place to test Einstein's 93-year-old theory, the international team of astrophysicists reported in the July 3 edition of the journal Science.