Google Joins MIT in Search ET Planets

Google has joined MIT scientists who are designing a satellite-based observatory -the Transiting Exoplanet Survey Satellite (TESS)- that they say could for the first time provide a sensitive survey of the entire sky to search for earth-like planets outside the solar system that appear to cross in front of bright stars. Google will fund development of the wide-field digital cameras needed for the satellite. "Decades, or even centuries after the TESS survey is completed, the new planetary systems it discovers will continue to be studied because they are both nearby and bright," says George Ricker, leader of the project. Most of the more than 200 extrasolar planets discovered so far have been much larger than Earth, similar in size to the solar system's giant planets (ranging from Jupiter to Neptune), or even larger. But to search for planets where there's a possibility of finding signs of living organisms, astronomers are much more interested in those that are similar to our own world. Most searches so far depend on the gravitational attraction that planets exert on their stars in order to detect them, and therefore are best at finding large planets that orbit close to their stars. TESS, however, would search for stars whose orbits as seen from Earth carry them directly in front of the star, obscuring a tiny amount of starlight. Some ground-based searches have used this method and found about 20 planets so far, but a space-based search could detect much smaller, Earth-sized planets, as well as those with larger orbits.