The splash of the impact of Fragment G of Comet Shoemaker-Levy 9 on Jupiter.  
The ring of hot gas is 33000 km wide, and it was expanding at 4 km/s.

The colour coding is 3.09 um (B), 3.42 um (G) and 3.99 um (R)

Images from Peter Mcgregor and Mark Allen, ANU 2.3m telescope at Siding 
Spring