NASA's Kepler Space Observatory revolutionized our view of exoplanets. When it became crippled, a daring innovation gave it a brand new mission. The mission ended this year when Kepler ran out of fuel in October.

One of the discoveries was the Kepler-22 system. The diagram shows how it compares to the Solar System. The habitable zone is where water can exist as a liquid. The star Kepler-22 is very similar to our Sun, but slightly smaller, so it's habitable zone is closer in.

Mona Evans
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