When these stars dance, they make their own music. Astronomers have tracked down the source of a mysterious radio signal from deep space repeating every two hours. Stunningly, it's a pair of stars in such a tight orbit that their magnetic fields regularly bump into each other — and it's this bodily percussion which is blasting out the radio emissions we're picking up on Earth.

He believes astronomers could now search for other signals from binary systems, possibly involving neutron stars or magnetars. A Decade-Long Search. The signals were first detecte