NASA has Googled the stars — and found new rocky planets in a 'major discovery'

NASA and Google announced a "major discovery"on Thursday: another solar system with eight planets

Astronomers already knew about the star system, called Kepler-90, and seven of its planets. But by using new artificial intelligence software developed by Google, researchers identified an eighth planet, called Kepler-90i, lurking in old data.

Kepler-90i appears to be a hot, rocky orb circling a sun-like star that's 2,545 light-years from Earth. The planet was found using a Google artificial intelligence system, which used machine learning to train itself and sift through data recorded by NASA's Kepler observatory — a space telescope that has stared down about 150,000 sun-like stars over the years to look for signs of distant planets.

Kepler-90i is the third planet from its sun and orbits the star once every 14 days, though it doesn't appear to be habitable: The temperature on Kepler-90i surface is likely a blistering 1,800 degrees Fahrenheit.

"Kepler-90i is not a place I'd like to go visit," Andrew Vanderburg, an astronomer at the University of Texas at Austin who helped find the planet, said during a press briefing.

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An illustration of the Kepler-90 star system and its planets compared to our solar system. NASA/Ames Research Center/Wendy Stenzel

Vanderburg was helped by Google AI software engineer Christopher Shallue. He noted how astronomers had already pored over 35,000 strong signals in Kepler data, but had skipped over weaker and less promising signals. Those weak signals were what Google analyzed — and how Kepler-90i was discovered.

"The way I see it, what we've developed here is a tool to help astronomers have more impact," Shallue said.

Vanderburg and Shallue also found a second new planet, called Kepler-80g, that seems similar to the TRAPPIST-1 system that harbors potentially habitable worlds.

Prior to this analysis, NASA's last examination of Kepler data confirmed 219 new worlds in the more than 4,000 candidates that two Kepler missions had turned up. The space agency's total of confirmed exoplanets in Kepler's data is now 2,525 — 10 of which may be rocky, Earth-size, and possibly habitable to alien life.

How NASA Googled for new worlds

To detect two new planets, Vanderburg and Shallue fed their Google system data that astronomers had already analyzed. These were roughly 15,000 "yes, this is a planet" and "no, this is not a planet" classifications. The system trained itself on these classifications, using what's known as a convolutional neural network — software that mimics the way the human brain processes information.

Shallue told Business Insider there's not yet catchy a name for the new system system, but said it's very similar to a cats-and-dogs model that Google developed to — with a little bit of human input at the start — train itself to identify the animals in pictures.

NASA and Google say its new technology will help astronomers find many more exoplanets in the future. In this case, the new cats-and-dogs system only studied 670 star systems — but Kepler has monitored about 150,000 star systems.

In fact, Vanderburg believes the Kepler-90 solar system may have more planets that we have yet to detect.

"It would almost be surprising to me if there weren't any more," he said. "Is an eight-planet solar system like our own really that extraordinary? Maybe there are systems out there with so many planets, they make our solar system seem ordinary."

The coming era of AI-powered astronomy
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An artist's rendering of NASA's Transiting Exoplanet Survey Satellite, or TESS mission. NASA's Goddard Space Flight Center
For those wondering whether Google's AI system could make astronomers obsolete, NASA says not to worry.

Jessie Dotson, a Kepler project scientist at NASA's Ames Research Center, explained that astronomers will always be needed to classify objects before feeding information into a neural network, so that the AI can learn how to look at new data.

"This will absolutely work alongside astronomers," Dotson said. "You're never going to take that piece out."

If anything, said Sara Seager, a planetary scientist at MIT who wasn't involved in the research, there's a major lack of astronomy data that's labeled well enough for algorithms to teach themselves on.

"Data from Kepler that the team used for training took years before enough was figured out to get to the auto-vetting point," Seager told Business Insider. "Also, people may eventually want to look at all data — you can't find what you aren't looking for."

Even more exoplanet data is about to pour in, too.

Seager is working on NASA's next-generation spacecraft to hunt for new worlds, called the Transiting Exoplanet Survey Satellite or TESS mission. It will complement Kepler's search by monitoring 200,000 of the brightest stars in the night sky for exoplanets and is currently slated to launch no earlier than March 2018.

Dana Varinsky contributed to this report.

Note: This story was published prior to NASA's media teleconference and significantly updated afterward.

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