Scientists Spot First Possible Exoplanet Outside Milky Way

A possible Saturn-sized planet identified in the distant Whirlpool galaxy could be the first exoplanet to be detected outside the Milky Way.

- Linda Geddes

The exoplanet candidate appears to be orbiting an X-ray binary-made up of a normal star and a collapsed star or black hole - with its distance from this binary roughly equivalent to the distance of Uranus from the sun. The discovery opens up a new window to search for exoplanets planets orbiting stars beyond our sun - at greater distances than ever before. Although nearly 5,000 exoplanets have been detected so far, all of them are in the Milky Way galaxy - with few further than about 3,000 light years from Earth.

An exoplanet in the spiral Messier 51 (M51) galaxy - also called the Whirlpool galaxy because of its distinctive shape - would be about 28m light years away.