Astronomy Picture of the Day



Unexpected Impact on Jupiter
Credit: ALPO, Theo Ramakers

Explanation: Two months ago, something unexpected hit Jupiter. First discovered by an amateur astronomer Anthony Wesley on 2009 July 19, the impact was quickly confirmed and even imaged by the Hubble Space Telescope the very next day. Many of the world's telescopes then zoomed in on our Solar System's largest planet to see the result. Some of these images have been complied into the above animation. Over the course of the last month and a half, the above time-lapse sequence shows the dark spot -- first created when Jupiter was struck -- deforming and dissipating as Jupiter's clouds churned and Jupiter rotated. It is now thought that a small comet -- perhaps less than one kilometer across -- impacted Jupiter on or before 2009 July 19. Although initially expected to be visible for only a week, astronomers continue to track atmospheric remnants of the impact for new information about winds and currents in Jupiter's thick atmosphere.
It’s interesting that the impact hole in the clouds took six times longer to dissipate than was expected.

How little we know about even our own star system.