When you think of crowdsourcing, you might think of artists seeking supporters on Kickstarter or Patreon, but probably not a NASA-powered program seeking other planets.
Exoplanet Explorers is part of the online Zooniverse platform, which literally lets anyone sort through data from NASA’s Kepler space telescope to see if anything undiscovered is floating out there. Kepler follows Earth and searches for unknown exoplanets by watching the stars they may orbit, since a transiting planet will cause a temporary dip in brightness.
The K2 mission has computer programs singling out stars with sudden brightness dips until astronomers can determine whether or not a particular star could host any planets, except the immense amount of data can be overwhelming for astronomers. That’s where you come in. Citizen scientists jumped on the Kepler data when the program first launched in 2017, with 287,309 stars observed since. It might have sounded like one of those games you can easily get obsessed with but never really win— until researchers confirmed that data found by people like you, on their sofas and smartphones, was actually proof of an undiscovered system.
"People anywhere can log on and learn what real signals from exoplanets look like, and then look through actual data collected from the Kepler telescope to vote on whether or not to classify a given signal as a transit, or just noise," says NASA JPL/Caltech staff scientist Jessie Christiansen, who recently published the study with colleagues, per a post on Caltech.edu.
Potential transit signals get at least 10 pairs of eyes on them and need at least a 90 percent vote before that star can be considered a viable candidate for further study. That shouldn’t be a problem, considering that over 10,000 users sent in upwards of 2 million classifications in the first 48 hours after the project was broadcast on the ABC Australia TV series Stargazing Live.
It was Christiansen who found a star with multiple transits shining among the data. With 100 percent “yes” votes on three of four planets from more than ten people and 92 percent on the fifth, the very first completely crowdsourced planetary system had been discovered.
“We decided to look for a multi-planet system because it's very hard to get an accidental false signal of several planets,” she said.
There are at least five exoplanets and a possible sixth in the system K2-138. The five planets we definitely know exist range from Earth- to Neptune-size and orbit a star slightly smaller and cooler than the sun. Planet B could possibly be a rocky super-Earth, while the others are thought to be ice and gas giants. Not that anyone (or anything) will be landing on them soon — they’re all scorching. Think temperatures from 800 to 1,800 degrees Fahrenheit Their orbital periods are so short that a year on one of these planets is 13 days.
Something else is going on here. There is a unique chain of orbital resonances in the K2-138 system, meaning each planet takes 50 percent longer to orbit the star than the next planet further in. No other system with a resonance chain like this has ever been found. It could be a portal to how these planets formed billions and billions of years ago.
So next time you’re playing Candy Crush on your phone, just think that you could be discovering planets.
(via NASA JPL)