NASA’s Kepler Mission Confirms Its First Planet in Habitable Zone of Sun-like Star
NASA’s Kepler mission has confirmed its first planet in the “habitable zone,” the region where liquid water could exist on a planet’s surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.
The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.
A diagram to help people envisage how the Kepler-22 system compares to our arrangement of planets.
I will take this opportunity to emphasize once again that it is not yet possible to know whether this planet (or the other candidates) are Earth like; we only know they are Earth sized (in the case of Kepler-22b slightly larger than the Earth) and are in orbits that could allow for liquid water on their surfaces.
Also, the number of Kepler candidate planets are multiplying rapidly. Our galaxy is likely awash with planets. Kepler satellite’s main goal was to get a statistical count of planets and their distribution, and it is performing magnificently. Hopefully Congress can find the few million dollars to fund an extended mission while the satellite is still operational.