NASA has discovered an eighth planet around a distant star, which means we’re no longer the largest solar system we know of. The discovery was made thanks to some artificial intelligence help from Google, which found the planet by scouring previously overlooked “weak” signals in data captured by the Kepler Space Telescope. The newly found planet is located in the solar system around Kepler-90, a star about 2,500 light-years away from Earth that was previously discovered in 2014.
The Kepler Space Telescope has been searching the galactic sky for exoplanets, or planets outside our own Solar System, since it launched in 2009. In order to sift through all the data that it’s captured since that launch, scientists usually look at the strongest signals first. And that process has worked well enough so far. NASA has confirmed 2,525 exoplanets in that time, a number that has changed our understanding of how common it is to find planets around the stars that make up our galaxy.
Recently, though, artificial intelligence has become a more prominent tool in astronomy. Scientists — including ones who work on the Kepler data — have increasingly turned to machine learning to help sort through typically lower-priority data to see what they might have missed. In the process, they found an overlooked planet that’s now named Kepler-90i.
But while we now know that Kepler-90 has the same number of orbiting planets as our Sun, the solar system is a poor candidate in the search for extraterrestrial life — or at least, life as we know it (especially compared to something like the planets that surround TRAPPIST-1). Kepler-90 is about 20 percent bigger and 5 percent warmer than our Sun. And its eight planets dance around the star in much closer orbits than the ones in our own Solar System. In fact, their orbits are so comparatively small that seven of Kepler-90’s eight planets would fit in between the Earth and the Sun.
The discovery of Kepler-90i, came after NASA let Google train its machine learning algorithms on 15,000 signals from potential planets in the Kepler database. The scientists then took the trained system and set it to work on data from 670 stars that were already known to have multiple planets, as they considered those to be the most likely hiding places. The newly discovered planet in Kepler-90, along with one other found in the Kepler-80 solar system announced today, are the first NASA was able to confirm from these new results from Google’s AI.
The inclusion of machine learning in this process shouldn’t scare humans whose livelihood revolves around discovering and studying exoplanets, according to Chris Shallue, a senior Google AI software engineer who worked on the project.
“What we’ve developed here is a tool to help astronomers have more impact,” Shallue said on a conference call about the news. “It’s a way to increase the productivity of astronomers. It certainly won’t replace them at all.”