Kepler-22b, the first planet outside our solar system confirmed to be within its star’s habitable zone by the Kepler spacecraft, orbits a G-type star 600 light years away, and has a day 290 Earth days long (we’ll probably never learn how long its own day is). That doesn’t sound too different from our own planet, but at 2.4 times Earth’s radius it’s substantially larger, which is to say it’s a super-Earth. Questions probably never to be answered: whether it has a breathable atmosphere or liquid water, whether it’s rocky, watery, metallic or gaseous, or whether it’s inhabited. It’s out there: that’s about it. Image credit: NASA/Ames/JPL-Caltech (artist’s conception).