The web site SpaceWeather.com is carrying a report from astrophotographer Anthony Wesley saying
"Jupiter has been hit by something similar to the Shoemaker-Levy 9 impacts in 1994. There is a jet black circular impact mark near its south pole that I imaged tonight from my observatory in Murrumbateman, Australia.
I have imagery of that same location from 2 nights earlier without the impact mark so this is a very recent event. This image shows that the material has already begun to spread out in a fan shape on one side, and should be rapidly pulled apart by the fast jetstream winds. I'm sure this will generate some interest around the astronomy community, as impacts like this are rare. I recorded a lot of footage, and will be generating more images and a rotation animation."
SpaceWeather is calling on amateur astronomers around the world to monitor developments on Jupiter. What a nice way to celebrate the anniversary of the first moon landings.