article_snippet.sent: Since then, ground-based surveys and NASA's Kepler satellite have discovered nearly 2,000 confirmed "exoplanets," and thousands more candidates await confirmation.
article_snippet.sent: Many of these planetary systems are quite unlike our own solar system.
article_snippet.sent: Some have large planets like Jupiter that orbit Some stars far closer than Mercury, the innermost planet in our solar system.
article_snippet.sent: But smaller rocky planets like Earth, though harder to find, appear to be even more abundant.
article_snippet.sent: Extrapolating from discoveries to date, astronomers estimate there are perhaps 40 billion Earth-like, habitable-zone planets in our Milky Way galaxy alone.
article_snippet.sent: If the half dozen or so rocky, Earth-like exoplanets now known are similar, the odds of discovering humanlike life on the half dozen or so rocky, Earth-like exoplanets now known are similar are about the same as, well, winning your state lottery with one ticket.
article_snippet.sent: Of course, if there are 40 billion Earth-like planets out there, the odds of discovering humanlike life on them improve quite a bit.