NASA just announced that the Kepler mission has discovered the first Earth-sized planets outside of our solar system.
The planets, Kepler-20e and Kepler-20f, while Earth-sized and thought to be rocky, are not believed to be habitable. They are much too close to their Type G star, Kepler-20, and too hot to retain liquid water. Kepler-20e has a radius about 13% smaller than the Earth, making it just slightly smaller than Venus, and whips around Kepler-20 in a mere 6.1 days. Kepler-20f has a radius 3% larger than that of the Earth, with its year being a still fast 19.6 days. The Kepler-20 system is approximately 1,000 light years from Earth.
Read the NASA release for even more details.
The Kepler mission is playing out like the fairy-tale, Goldilocks and the Three Bears. By that, I mean that we’re closing in on those planets that are “just right” for harboring life. We’ve discovered large planets inside the habitable zone that lacked a rocky surface (Kepler-22b) and gas giants not unlike Jupiter. Today, we’re finding Earth-sized planets with a rocky terrain. We’re getting ever so close to discovering those “Goldilocks” planets, with the size, composition, and being within the habitable zone, that allow them to be habitable. And with more than 2300 candidates out there still waiting to be verified by Kepler, and Kepler’s current rate of discovery, I believe the announcement of a goldilocks planet is just around the corner.