The Kepler telescope finds hundreds of distant planets

An illustration of Kepler-186f, a potentially habitable exoplanet discovered in April. (NASA-Ames/SETI Institute/JPL-CalTech

Prior to 2014, scientists had confirmed the existence of about 1,000 exoplanets (planets that orbit other stars). But in a single announcement in February, scientists announced that using data from the Kepler telescope, they'd found an additional 715 new planets. Soon afterward, in April, astronomers announced that 500 light years away, they'd found a roughly Earth-sized one (illustration above) that might be the right temperature for liquid water.
These planets are mostly too far away for us to learn much more about, but over the next decade, a new generation of telescopes will search for closer planets and allow us to analyze their atmospheres. Some scientists think that within a generation, we may even be able to spot signs of distant alien life.