Giant Planet Found Lurking Inside the Milky Way's Galactic Bulge

Astronomers have discovered a giant world orbiting a star using a quirk of Einstein’s general relativity. This “microlensing” event enabled astronomers to test a new survey technique to detect the alien world from more than 25,000 light-years away, deep inside the Milky Way’s galactic bulge.

Microlensing events occur when a star passes in front of another more distant star. As the nearer star passes in front, its gravitational field — which is (according to general relativity) bending the surrounding spacetime — deflects the light from the more distant star. Like the lens in a magnifying glass, the starlight is magnified and Earth-bound observatories are able to spot a transient brightening. Information about the “lens” (the foreground star) and any planets in tow can then be deduced. Read more...