Comet Shoemaker–Levy 9 chains on the Jovian moons did not lead back to a larger crater. The impact of SL9 strongly implied that the chains were due to trains of disrupted cometary fragments crashing into the satellites. On July 19, 2009, exactly 15 years after the SL9 impacts, a new black spot about the size of the Pacific Ocean appeared in Jupiter's southern hemisphere. Thermal infrared measurements showed the impact site was warm and spectroscopic analysis detected the production of excess hot ammonia and silica-rich dust in the upper regions of Jupiter's atmosphere. Scientists have concluded that another impact event had occurred, but
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