The Sky May Be Filled with Earth-like Planets

One of the biggest questions in astronomy today is easy to ask, and incredibly hard to answer: How many Earth-like planets are there in the Universe? By Earth-like, I mean planets roughly the size of Earth, and which are also roughly the same temperature as Earth. So we can ignore frigid iceballs far from their stars, boiling lava planets too close in, and giant and dinky planets. We want to know about potentially habitable planets, where life as we know it has a shot at getting a toe (or pseudo...