I have blogged before about Kepler, a recently launched spacecraft that will search for Earth-sized planets around other stars. It is finally getting ready to start taking data and NASA just released the first light images (click to embiggen).
This may not look like much, but that's because this covers a huge area of sky. There are about 14 MILLION stars in this field! 100,000 of them are going to be monitored for planets passing in front of them, causing their brightness to temporarily dip a very small amount (about a few parts in 10,000 or so). You can see they makes star cluster NCG 6791 and Tres-2, a star with an already known planet in orbit (a Jupiter size planet orbits it about every 2.5 days). Let's zoom in on NGC6791 to see what this guy can really do.
NGC6791 is a very old (~8 billion years) cluster in Lyra. It has over twice the iron content of the Sun making it very unusual. There are also white dwarfs, some of which appear to be 4 billion years old and some 6 billion years old indicating that there may have been multiple bursts of star formation. It is an open cluster...open clusters usually disperse within a billion years. This cluster is a real oddball.
Now Kepler, after all its instruments pass their checks and calibrations, will stare at this part of the sky for years, hoping to find those little dips of light that indicated the presence of other planets. Hopefully, we will be one step closer to answering one of the big questions: Are we alone?