Less than 20 years after first finding a planet beyond our solar system, astronomers are poised to hit a big milestone — the discovery of alien world No. 500.
As of Tuesday (Oct. 12), the confirmed tally stands at 494 extrasolar planets, with more than 70 discovered so far in 2010 alone. At that rate, No. 500 could be announced before October is out — just a month or so after another watershed moment, the discovery of the first potentially habitable alien planet.
"Where we are, I'd expect that by the end of October, we'll be at 500 if things keep going the way they're going," said Jon Jenkins of the SETI (Search for Extraterrestrial Intelligence) Institute. Jenkins is the analysis lead for NASA's planet-hunting Kepler mission.
And the 1,000th world could be discovered surprisingly soon, as the space-based Kepler mission has already offered up hundreds of planet candidates that await further observation and confirmation.