In early June, 2010, something probably a kilometer across slamed into Jupiter's atmosphere. Ramming through the dense gas at speeds of 80 km/sec, it quickly slowed to a stop, detonating violently as all its vast kinetic energy was converted into a mind-numbing explosion which was the equivalent of a million one-megaton bombs!
Anthony Wesley, an accomplished amateur astronomer in Australia, not only discovered the event (which lasted mere seconds) but also caught it on video and made this color composite image of the titanic detonation. Diminished only by distance, the flash of light you can see to the lower right is the proof of the impact; if something this size were to hit the Earth it would bring terrible devastation to our planet. It would only be a fraction of the dinosaur-killer asteroid impact, but still enough to lay waste to an entire country and have global effects. It might not spell the end of humanity, but all in all I'd rather it didn't happen!Get the hi-res version here.Image credit: Anthony Wesley