First Planet Discovered… Outside Our GALAXY!? (Maybe…)

I’m sure that many people are aware that astronomers are scouring our own Milky Way Galaxy looking for evidence of planets orbiting other stars.  So far, they have discovered over 300 planets orbiting stars other than the Sun.  These planets are known as  extra-solar planets, or, exo-planets.  They range in size from a few times the mass of Earth, to several times the mass of Jupiter.  Recently, NASA launched the Kepler Mission, which is a telescope that will scan 100,000 nearby stars to find evidence of more exo-planets, hopefully down to the size of Earth.  If any planet transits, or passes in front of its parent star, the light from that star will slightly dim, and Kepler will be able to detect that.  From that information, astronomers will be able to determine the mass of the planet, or object passing in front of the star.

More information about how Kepler will be able to detect planets orbiting these stars can be found here:

http://kepler.nasa.gov/about/#anchor409142

However, today, thanks to Nancy Atkinson, over at Universe Today, I learned that a team of Astronomers in Italy may have taken this search for extra-solar planets to a whole new level!  They think they may have discovered a planet orbiting a star in the Andromeda Galaxy! (M 31) The Andromeda Galaxy is similar to ours, in that it’s a spiral galaxy, but it’s over 2 million light years away!

To find out how they did this, check out the story at the Universe Today website:

http://www.universetoday.com/2009/06/10/first-extra-galactic-planet-may-have-been-detected/

Why would a discovery like this be important? For one thing, it would mean that planetary formation around stars is not unique to our own galaxy.  (Not that we should expect it to be.)  It would also show that if  planets exist in other galaxies, then the opportunity for life to take hold and develop and evolve is also greatly increased.  Whether that life is intelligent or not, is another question.

All in all, this is incredibly exciting news!