astroengine writes "The Kepler space telescope's prime objective is to hunt for small worlds orbiting distant stars, but that doesn't mean it's not going to detect some extreme relativistic phenomena along the way. While monitoring a red dwarf star — designated KOI-256 — astronomers detected a dip in starlight in the Kepler data. But it wasn't caused by an exoplanet. After some careful detective work, the researchers found that the red dwarf was actually in orbit around a binary partner — a white dwarf. As the white dwarf passed in front of the red dwarf, the starlight was enhanced by microlensing — a phenomenon caused by an intense gravitational field focusing light from behind. This had the counter-intuitive result of causing the starlight to dim when the white dwarf passed behind the red dwarf and then brighten as the white dwarf passed in front. This is one of the first discoveries of a binary partner through microlensing. 'Only Kepler could detect this tiny, tiny effect,' said Doug Hudgins, Kepler program scientist at NASA Headquarters, Washington. 'But with this detection, we are witnessing Einstein's theory of general relativity at play in a far-flung star system.'"