The 500th alien world appears to have been discovered, according to extrasolar planet trackers.

Less than 20 years after confirming the first planet beyond our own solar system, astronomers have bagged exoplanet No. 500. The milestone was reached Friday (Nov. 19), according to the Extrasolar Planets Encyclopedia, a database compiled by astrobiologist Jean Schneider of the Paris-Meudon Observatory.

As of today (Nov. 22), the count stands at 502 alien worlds, the database reports.