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Citizen Scientists may have found two new Earth-like planets, using Planet Hunters

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Citizen Science made an amazing leap this week. Citizen scientists, using the data supplied by the Kepler public archives, helped to identify two possible planets outside of our solar system, thanks to the browser game Planet Hunters.

The 10 best candidates as sifted through by citizen scientists during the first month afterPlanet Hunters went live were passed onto the Kepler team, a group of scientists all over the world looking to find extra-solar planets, for further inquiry. The results were published in the article Planet Hunters: The First Two Planet Candidates Identified by the Public using the Kepler Public Archive Data, published in the journal Monthly Notices of the Royal Astronomical Society this week.


NASA' Kepler Mission to find Earth-like Planets Orbiting other Stars
Launched in 2009 and orbiting for a minimum of three years, the Kepler Space Telescope is focused on a group of 200,000 plus stars near the constellation Cygnus in hopes of finding habitable, Earth-like planets. Kepler looks at these stars, taking light measurements every thirty seconds in hopes of finding a slight dimming in light intensity. This generated a tremendous amount of data, but data that can be used to generated light curves that communicate how the light from a star can vary over a period of several months.


Planet Hunters Game Play
Planet Hunters works by using an indirect approach to finding planets, making use of the Transit Method and the Kepler Public Data archive. By observing the light emitted by stars over a 30+ day period, users are asked to look for times when the light curve "dips" in signal. This dip in signal, called a transit feature, suggests that a possible planet in orbit around the star is moving across the path of the star at the time. It takes about three hours for a planet to move across the face of the star during its orbit, long enough for hundreds of light measurements to be made, resulting in dips called transits. Your challenge, as a player, is to identify these dips in light intensity over a course of time for a given star. Also, the size of the planet plays a role, so if a planet is very large, the depth of the transit will be larger than that of a smaller planet, as the larger planet would block more light.

Why use Citizen Scientists?
There is simply too much data for the Kepler Team to sift through individually. Kepler monitors 200,000 stars and takes images every thirty seconds, with the light curves generated needed to be checked by several eyes before a consensus can be reached. Opening up the data to citizen scientists allows thousands of individuals to sift through the data, acting like a giant supercomputer, and you to help look for planets outside of our solar system. Each user name that took part in analyzing the data that was reported in the paper also had their name included in the acknowledgements section of the paper. Planet Hunters has grown to accompany more than 40,000 users, with over four million observations made on the data sets and 69 possible planets discovered, which the Kepler Team will now look into. A new set of public observation data from Kepler, the third in the series so far for Planet Hunters, was released last week.


Images courtesy of NASA, the AP, and Planet Hunters. The top image is an artist's rendition of the Kepler Space Telescope supplied by the AP. Sources linked within article.