At the beginning of this year, we were excited to help break the news of the 9th planet confirmed by the Kepler spacecraft. Not even an entire year later, Kepler is up to 28 confirmed planets and more than 2000 more candidates waiting to be studied and potentially verified!
Last week, the Kepler mission had a very exciting announcement: Kepler-22b became the first exoplanet to be located within the habitable zone.
So let’s take a look at this exoplanet. Kepler-22b has a radius around 2.4 times that of the Earth. It is located 587 light-years from Earth, orbiting a star not so much different than our own. Though Kepler-22b’s host star — Kepler-22 — is slightly smaller and cooler than the Sun, Kepler-22b orbits closer than the Earth does to the Sun, compensating for the difference. Kepler-22b’s mass and surface composition is still unknown.
(Diagram showing a comparison between our solar system’s habitable zone with Kepler-22’s. / Credit: NASA/Ames/JPL-Caltech)
So, we have a planet not too much larger than the Earth (though we don’t know its composition or mass), orbiting a star not too much smaller/cooler than our Sun, in the so-called habitable zone. What are the chances of life? First, we have to remember that while the Earth sits in our solar system’s habitable zone, so does Mars, Ceres, and sometimes Venus, and those are hardly bodies that appear to be very conducive for life (though, I think the book on Mars still has many pages to be read). But, then there’s the Earth, that Goldilocks planet within Sol’s habitable zone; life flourishing.
So. Not only is Kepler looking in the right places but it is finding what it is looking for, and proving quite able to find out just how rare planets like our own might be. At 587 light years from Earth we won’t be sending a probe to Kepler-22b to do reconnaissance anytime soon, but this discovery does fuel our imaginations, fill our minds with knowledge, and inspire us to carry on looking. At the very least, it proves just how capable the Kepler spacecraft is and just how amazing the mission truly is.