MIT scientists started a project with the help of Google to find other planets with similar characteristics as Earth. For that, they are designing a satellite-based observatory that will be able to scan the entire sky. The current technology discovered around 200 extrasolar planets so far, but all of them have a much bigger size than Earth.

The difference between searches made so far and the new system is that the first ones depend on the gravitational attraction that planets exert on their stars in order to detect them (so they are best at finding large planets that orbit close to their stars); the new method of scanning planets outside our solar system will be searching for stars with orbits, as seen from Earth, that carry them in front of the star, obscuring a small amount of starlight. Astronomers are much more interested in the planets that have the same size and, eventually, the climate and resources alike to the ones existing on Earth because these planets have the most chances of hosting living organisms.

The satellite will be named TESS (Transiting Exoplanet Survey Satellite) and could potentially be launched in 2012. It is expected that by 2013 TESS to find hundreds of planets like Earth. After that, NASA will have to build spaceships or robots to travel and explore these new grounds, which could take much longer than 4 years…

Source