Do they come in peace? Astronomers at the University of California-Berkeley and the University of Hawaii released a study Monday saying there are likely around 40 billion planets with Earth-like characteristics in our galaxy. The closest one? 12 light years away, or 72 trillion miles. And just in case you weren’t blown away yet, experts now believe that one in five stars similar to our sun have a planet the same size as earth with a temperature favorable to life.