Print Edition: May 22, 2013
Maybe you don’t have the fortitude of James Cook or the navigational aptitude of Magellan, but those explorers didn’t have a laptop and the data from one of NASA’s Keplar space observatory at their disposal.
Thanks to the work of the Planet Hunters science team, all you need to help discover a new planet is a web browser and an internet connection.
Planet Hunters is an interactive citizen science project that draws on the power of web communities to analyze massive amounts of data for patterns and nuances missed by even the most advanced computer algorithms. Hailing from around the globe, thousands of amateur scientists are doing their part to identify planet candidates from among countless solar systems.
So how does it work? When an orbiting object, say a planet, passes in front of a star, it casts a tiny shadow. The star’s light output blinks during the object’s passage.
Participants in the Planet Hunters project are asked to examine graphs that show the amount of light emitted from one of 130,000 distant stars measured in 30-minute increments by the Keplar space observatory.
Yale astronomer Meg Schwamb, a member of the Planet Hunters science team, explains that regular dips in the volume of light indicate an object passing between the star and the Keplar’s data sensors.
“When a planet moves in front of a star, it reduces the light,” she explains. “The repetition of that event tells you the orbital period, so the year. And the depth tells you the size of that planet.”
Each orbit is known as a transit event. Transit events can be caused by moons, asteroids, binary stars or exoplanets waiting to be discovered.
“People can sometimes outperform automated algorithms,” she says. “With Planet Hunters, we’re putting the data in a form that is accessible to everybody.”
Once users isolate a planet candidate from among the graphs, the Planet Hunters science team steps in to determine the relative size of the transiting object. Schwamb and her colleagues aim their telescopes and other scientific instruments toward the planet candidate and perform a series of rigorous tests to determine sources of interference that might contribute to a false positive.
“Volunteers are very good at finding planet transits of Neptune size or larger,” Schwamb explains. Smaller planets leave a much fainter trace, making them more difficult for the untrained eye to notice.
Thanks to the help of over 250,000 participants, the team has announced its first confirmed planet, with 20 more planet candidates currently under investigation. PH1b, the newly-discovered planet, is also the first known planet to be a part of a four-star system.
“This was found by human eyes searching through the data,” Schwamb says. “There’s many discoveries like that hiding in the Kepler data set. There’s so much left to pursue that we’re just starting to work on.”