How common are Earth-sized planets?
extrapolations from new data taken by NASA's orbiting
are indicating that at least one in ten stars are orbited by an
Earth-sized planet, making our Milky Way Galaxy the home to over ten
Unfortunately, this estimate applies only to planets effectively inside
the orbit of Mercury, making these hot-Earths
poor vacation opportunities for humans.
This histogram depicts the
estimated fraction of stars that have close
orbiting planets of various sizes.
The number of Sun-like stars with Earth-like planets in Earth-like
orbits is surely much less, but even so, Kepler has also just announced
the discovery of
four more of those.