The Impact Event on Jupiter in 2009 

One of HST’s most cited set of observations was the series of images taken in July 1994 as the dishevelled remnants of Comet Shoemaker-Levy 9 crashed into Jupiter. That event highlighted the catastrophic consequences of cosmic impacts, and sparked considerable interest in identifying earth-crossing asteroids and comets. Fifteen years later, on 19 July 2009, an Australian amateur astronomer, Anthony Wesley, noticed a strange dark ‘scar” near Jupiter’s southern pole. The feature was quickly confirmed by other astronomers, both amateur and professional, and was quickly judged as likely to be the result of another, completely unexpected, cometary impact. The SL9 impact was thought to be a once-in-a-lifetime (if not more) event; clearly, the impact rate is higher than previously suspected. At the time of the new event, HST was deeply immersed in the initial on-orbit instrument performance tests, but the science staff were able to interrupt those procedures for a few orbits to obtain images with Wide-Field Camera 3. Further observatio9ns will be obtained at a later date to track the evolution of the feature, as Jovian winds disperse the detritus through the atmosphere.

Source: The Space Telescope Science Institute