Bizarre binary star system pushes study of relativity to new limits

An international team of astronomers and an exotic pair of binary stars have proved that Albert Einstein's theory of relativity is still right, even in the most extreme conditions tested yet. The results of their research are described in the April 26 issue of Science . "The unusual pair of stars is quite interesting in its own right but we've learned it is also a unique laboratory for testing the limits of one of our most fundamental physical theories, general relativity," says University of Toronto astronomy professor Marten van Kerkwijk , a member of the research team. What makes the pair of stars exceptional are the unique characteristics of each and their close proximity to each other. One is a tiny but unusually heavy neutron star - one of the most massive confirmed to date. Named PSR J0348+0432, it is the remnant of a supernova explosion, and is twice as heavy as the Sun yet is only 20 kilometres across. The neutron star is a pulsar that gives off radio waves that can be picked up on Earth by radio telescopes.