Strange New Worlds: The Amazing Alien Planet Discoveries of 2013

While astronomers didn't bag that elusive first "alien Earth" in 2013, they made plenty of exciting exoplanet discoveries during the past year.

Here's a list of the top exoplanet finds of 2013, from a tiny world about the size of Earth's moon to a blue gas giant on which it rains molten glass:

The smallest exoplanet

In February, astronomers announced the discovery of Kepler-37b, the smallest alien world ever found around a sun-like star. The planet is about 2,400 miles (3,900 kilometers) wide, making it just slightly larger than Earth's moon

Kepler-37b, which was spotted by NASA's prolific Kepler space telescope, lies about 215 light-years from Earth. The exoplanet is likely far too hot to host life as we know it; it zips around its parent star once every 13 days. Read more...