Space.com - 12/26/13, Mike Walls
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. [9 Exoplanets That Could Host Alien Life