Interloper Star in Our Galaxy
Astronomers have for the first time discovered a planet in the Milky Way that came from another galaxy. The planet, which has a mass of at least 1.25 Jupiters, orbits an elderly star that was ripped from a small satellite galaxy some 6 to 9 billion years ago. Johny Setiawan and Rainer Klement of the Max Planck Institute for Astronomy in Heidelberg, Germany, describe the finding online November 18 in Science. 'The coolness factor is definitely that the planet and star came from another galaxy,' says Sara Seager of MIT, who was not part of the study.