Comet Shoemaker–Levy 9 were observed, with the largest coming on July 18 at 07:33 UTC when fragment G struck Jupiter. This impact created a giant dark spot over across, and was estimated to have released an energy equivalent to 6,000,000 megatons of TNT (600 times the world's nuclear arsenal). Two impacts 12 hours apart on July 19 created impact marks of similar size to that caused by fragment G, and impacts continued until July 22, when fragment W struck the planet. Observers hoped that the impacts would give them a first glimpse of Jupiter beneath the cloud tops, as lower material was exposed
Comet ISON Central Bureau for Astronomical Telegrams identified the object as an asteroid, and it was listed on the Near Earth Objects Confirmation Page. Follow-up observations by independent teams were the first to report cometary features. Therefore, under the International Astronomical Union's comet-naming guidelines, Comet ISON was named after the team that discovered it, rather than the individual discoverers. After it was discovered in 2012, some media sources called Comet ISON the "Comet of the Century" and speculated that it might outshine the full Moon. An "Astronomy Now" columnist wrote in September 2012 that "if predictions hold true then Comet ISON will