Angry Birds Space is popular. That statement is something akin to “rock is hard” on the scale of most obvious things ever said, but a little specificity is useful: Rovio claims that the sequel to the smash hit Angry Birds has been downloaded 50 million times since it was released last month. That makes Angry Birds Space the fastest-growing (“selling” isn’t really appropriate here) mobile game of all time. The stat takes into account downloads on Android and iOS.

Angry Birds Space is certainly deserving of the title. After dozens of Season-themed additions to the original game, we were skeptical that setting the aggravated avians on a sky-high background would shake things up, but the addition of radial gravity and new play mechanics gives the game a completely new feel. Its first update added new ice-themed levels, and gave a preview of a possible Simpsons tie-in.

Better beware, though: fakes of Angry Birds Space have already started appearing. Rovio warned of unlicensed copies of the game that sent personal information to unknown servers. Remember that the Android Market is the safest place to download Angry Birds Space (or any well-known app) for both free and paid versions. Given Rovio’s history, we fully expect many more updates and expansions in the coming weeks and months.