The discovery of exoplanets really kicked off in the last decade or so. NASA just announced they've discovered a total of 715 new planets, boosting the overall count to nearly 1,700.
The list includes four planets about two and a half times as big as Earth that are in the Goldilocks zone, a distance from their parent stars that supports liquid water at the planet's surface.
The discoveries were made with the National Aeronautics and Space Administration's planet-hunting Kepler space telescope before it was sidelined by a pointing system problem last year. The telescope, launched in 2009, spent four productive years staring at 160,000 target stars for signs of planets passing by, relative to the telescope's line of sight.
The tally of planets announced at a Nasa press conference on Wednesday boosted Kepler's confirmed planet count from 246 to 961.
Combined with other telescopes' results, the headcount of planets beyond the solar system, or exoplanets, now numbers nearly 1,700.