The Australian TV program ABC Stargazing Live with Brian Cox recently challenged its viewers to become citizen exoplanet finders. They succeeded within a couple of days in finding four “Super Earth” planets each about twice the size of earth.

The discoveries were made using data from the Kepler space observatory available on the Exoplanet Explorers site, which is hosted by the Zooniverse citizen science organization.

Kepler observes thousands of stars and records the stars’ brightness for long continuous periods. If a star’s planet comes between the line of sight with the earth, a dip in the star’s brightness can be seen in the data.

The width and depth of the drop in the light and the frequency of the dips provides clues to the size of the planet and its orbital period and distance from its star.

While the above diagrams are very clean and unambiguous, most real data is noisy and messy. Human’s are still much better than computer algorithms in spotting structures and unexpected features in such data and that is why citizen science volunteers can provide very useful services for the pro scientists who are collecting the data, especially when there are huge amounts of such data.

In this case, the dips of four planets were seen in the light output of a star in the Aquarius constellation 600 light years from earth. This video provides more details about these exoplanets: