Another Earth? Believe it or not but we are going to be one step closer to discovering a rocky planet like ours beginning in April of this year. Due to be launched sometime in April, Kepler will search for planets around distant stars in the Cygnus region of the galaxy. It will simultaneously be observing over 150,000 stars to check for any dip in the star light it sees. This is basically called the transit method and occurs when a planet passes in front of the star thereby blocking some light from the star that we see. To make confirmation that the planet is actually there and was not a sunspot, Kepler will observe the same stars for the entire three year mission. This should give a planet multiple passes in front of its star to reach a confirmation of the findings. The planet’s size and where it is located compared to the star can then be calculated. Kepler hopes to find hundreds of additional planets over its three year mission with tens perhaps hundreds of rocky planets like the earth.
To this date there have been over 330 extrasolar planets discovered. Corot, led by the French is another satellite that is already in orbit searching for extrasolar planets. Having been functioning for almost two years now, it has found 7 planets so far with tons of data that could be planets but have not been confirmed yet. Just recently, it discovered a rocky planet that is only 1.7 times the mass of earth. This planet, however is way too close to its parent star to support any kind of life but it shows that the technology is there to detect earth size planets. The vast majority of planets found so far have been classified as “hot jupiters” which are gigantic gas planets often many times the mass of jupiter that orbit very close to their parent star. One exception has been with the star Gliese 581. This star is called a red dwarf and it has been confirmed that this star has a total of at least 4 planets. Two of these planets are on the very edge of the habitable zone (zone where liquid water can stay in liquid form) but are probably too hot on one extreme and too cold on the other. This is the first star system though with a similiar setup like our own solar system.
With the launch of Kepler we will be getting one step closer to the best question ever asked: Are we alone in the universe? For, if Kepler does detect numerous rocky planets (especially in the habitable zone) then our place in the universe just got a little smaller. The one thing Kepler will not be able to tell us will be whether there is life on any planet it finds or what the atmosphere is made of but it will give us a great look at how many places are out there to choose from for future planet finding missions. One mission currently on the drawing board but not yet approved is the terrestrial planet finder which could tell us what the atmosphere of any extrasolar planet contains. Wow! It truly is a great time to be alive!