James Glanz
Theorists are losing sleep over a brilliant x-ray source that appeared in the sky last December. The object, thousands of light-years away from Earth in the direction of the galactic center, is an unprecedented hybrid: the only known x-ray source that combines regular, oscillating emissions like those recorded from some sources with the erratic flashes seen from others. Theorists believed that those behaviors could not coexist, so the new object promises to shake up their understanding of the thousands of x-ray sources that dot the galaxy.