PORTLAND, Ore. - NASA astronomers have found a new way to perform fundamental physics research on ultra-dense objects like black holes, yielding the latest confirmation of Einstein's theory of relativity.

NASA's Goddard Space Flight Center (Greenbelt, Md.) observed the predicted distortion of space-time around the neutron star, Serpens X-1. Like black holes, neutron stars pack matter so densely that gravity distorts space and time. Using the ultra-sensitive instruments on the European Space Agency's XMM-Newton X-ray observatory and the Japanese/NASA Suzaku X-ray observatory, NASA scientists have experimentally confirmed Einstein's predictions about space-time distortions.

Specifically, the spectral line from hot iron atoms whirling in a disk around Serpens X-1 at 40 percent the speed of light were observed shifting to longer wavelengths and broadening asymmetrically by virtue of the Doppler effect in combination with the "beaming" effect predicted by Einstein's special theory of relativity.

NASA researchers confirmed their observations by detecting similarly distorted iron lines around two similar ultra-dense star systems.