Happy birthday to Comet Shoemaker-Levy 9 or at least our knowledge of it! It was discovered on this day in 1993.
Shoemaker-Levy 9 destroyed itself the following year by smashing into Jupiter. Many astro-psychiatrists believe it was off its meds. Be that as it may, the event provided new information about the composition of Jupiter as well as a sobering reminder that this kind of thing does happen in the universe, and sometimes not a comfortable zillion light years away.