Kepler Discovers 8-Planet System

Moments ago, NASA announced that the Kepler space telescope, for the first time ever, has discovered a star that has a system of 8 planets, similar to our own solar system.

Kepler Space Telescope, artist’s rendering. Credit: NASA/JPL

The exceptional part of the discovery is that it was found in existing Kepler data, using google artificial intelligence software that was trained to find positive detections in over 30,000 data sets.  Known as a neural network, the software was trained to look for patterns in the intensity of light from stars.  Normally, humans would need to do this work, but with so much data, there simply wasn’t enough brain power for astronomers to parse through it all.  By using confirmed planet detections from Kepler, the AI was trained to identify the difference between a true detection and a false pattern.  In testing, it reached an accuracy of 96%, and when applied to real data, it discovered two new planets in the existing Kepler data.

Kepler 90 planets’ size compared to our solar system. Credit: NASA/JPL


New planet raw data from Kepler 90-i and 80-g. Credit: NASA/JPL


Kepler 90-i, the new 8th planet in the Kepler 90 system, is not the farthest planet from the star Kepler 90.  It is one of the closer planets, having a short 14 day orbit.  All 8 planets in Kepler 90’s system are extremely close to the star, orbiting closer than Earth does to the Sun.

This new record for number of planets in an exoplanetary system is significant because we are reaching the cusp of finding star systems more populous than our own.  And the other interesting part of this story is that the there may be more planets in the Kepler 90 system.  Since all of the planets were found close to the star, there is plenty of room in the outer parts of the solar system for other planets to hide.  Kepler simply hasn’t spent time observing this outer region yet.

In planetarium shows, I often talk about how most stars are now thought to host planets, but some may have 10 or 20.  In the coming decades, we will likely be blown away by the discovery of massive planetary systems, but the real question becomes: Is our solar system big, small, or average? I can’t wait to find out!

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