Is Anybody Out There? 5/10

The recent discovery by the Kepler satellite of thousands of Earth-like planets where life could be possible, has given a big boost to the Search for Extraterrestrial Intelligence (SETI). In 2011, for the first time ever, Kepler provided us with a census of the Milky Way. We can now calculate how many stars in the Milky Way could have a planet like ours: around a billion.