Two years ago, Harvard astronomer Dimitar Sasselov stunned the world when he claimed there might well be 100 million Earth-size planets in the Milky Way. To some, the number sounded shockingly high. But the torrents of data that have come in from planet-hunters since then suggest that, if anything, the estimate was almost laughably low.
Just this month, researchers reported that there are probably more planets than stars in our galaxy, which would bring the total count well past the 100 billion mark. What's more, astronomers say the planets toward the lower end of the scale — "super-Earths" that are up to 10 times as massive as our own planet — are likely to be more common than Jupiter-scale planets.