Has Jupiter been struck by an object?

It would appear so. We see it in a ...

Preliminary image showing a black mark in Jupiters South Polar Region (SPR) which is almost certainly the result of a large impact - either an asteroid or comet - similar to the Shoemaker-Ley impacts in 1994.

This is on Anthony Wesley's web site, and what appears to be the outcome of an impact event has been photographed by him.

A bit of his post reads:

I started this imaging session on Jupiter at approximately 11pm local time (1300UTC). The weather prediction was not promising, clear skies but a strong jetstream overhead according to the Bureau of Met. The temperature was also unusually high for this time of year (winter), also a bad sign.

The scope in use was my new 14.5" newtonian, in use now for a few weeks and so far returning excellent images.

I was pleasantly surprised to find reasonable imaging conditions and so I decided to continue recording data until maybe 1am local time. By about midnight (12:10 am) the seeing had deteriorated and I was ready to quit. Indeed I had hovered the mouse over the exit button on my capture application (Coriander for Linux) and then changed my mind and decided instead to simply take a break for 30 minutes and then check back to see if the conditions had improved. It was a very near thing.

When I came back to the scope at about 12:40am I noticed a dark spot rotating into view in Jupiters south polar region started to get curious. When first seen close to the limb (and in poor conditions) it was only a vaguely dark spot, I thouht likely to be just a normal dark polar storm. However as it rotated further into view, and the conditions improved I suddenly realised that it wasn't just dark, it was black in all channels, meaning it was truly a black spot.

And you can read the entire exciting story here.