Confirmed Exoplanets Could Reach 500 by the End of This Month

Gliese 581

Artist's rendering of the star Gliese 581, with exoplanet Gliese 581c (neighbor to newly discovered Gliese 581g) in the foreground.ESO

If it seems like a new extrasolar planet is discovered every week these days, that's because there is. In fact, the rate is actually faster than one per week – 70 have been discovered thus far this year alone, bringing the overall tally of confirmed exoplanets at 494. At that pace we very well might hit exoplanet number 500 before the end of this month.

Now benchmarks are only benchmarks – like the Dow Jones Industrial Average hitting 11,000, the 500th exoplanet will be no more significant than finding number 499 or 501 from a scientific point of view. But it does speak to the rate at which research is producing results. The first definitive exoplanet was confirmed in 1992, and it's taken us almost two decades to cross the 500 threshold. But given the drastic uptick in discoveries and the increased scientific emphasis on exoplanet discovery, some researchers think we'll log number 1,000 in the next few years.

How? Better technology has allowed astronomers to assert with far greater certainty that a flicker in a star's brightness or a small wobble in its position is indeed caused by an orbiting body. That in turn has spawned increased interest in exoplanet research that has fueled the hunt. Dedicated instruments like NASA's Kepler mission, launched just last year, are turning up candidate planets at an extremely rapid pace.

While Kepler has only confirmed seven new alien planets thus far, it has located more than 700 potential worlds that are being further probed by other ground-based and orbital instruments. As researchers dig into Kepler's trove of candidates to separate the false leads from the true exoplanets, a cascade of confirmed discoveries could occur. The data and discoveries are pouring in at such pace that two mathematicians have predicted that – if their numbers are to be believed – we'll confirm the existence of a habitable, Earth-sized planet orbiting in its star's goldilocks zone in May of next year.

All that science is exciting, even if we haven't figured out how to travel throughout our own solar system just yet, much less to planets orbiting neighboring stars. Finding a potentially life-harboring rock out there would be monumentally significant regardless of whether it's exoplanet number 500, number 1,000, or any number in between.