Chicxulub crater is the larger Shiva crater, though the structure's status as an impact crater is contested. The collision of Comet Shoemaker–Levy 9 with Jupiter in 1994 demonstrated that gravitational interactions can fragment a comet, giving rise to many impacts over a period of a few days if the comet should collide with a planet. Comets undergo gravitational interactions with the gas giants, and similar disruptions and collisions are very likely to have occurred in the past. This scenario may have occurred on Earth at the end of the Cretaceous, though Shiva and the Chicxulub craters might have been formed 300,000 years
Comet Shoemaker–Levy 9 largest impacts. The waves were thought to be travelling within a stable layer acting as a waveguide, and some scientists thought the stable layer must lie within the hypothesised tropospheric water cloud. However, other evidence seemed to indicate that the cometary fragments had not reached the water layer, and the waves were instead propagating within the stratosphere. Radio observations revealed a sharp increase in continuum emission at a wavelength of after the largest impacts, which peaked at 120% of the normal emission from the planet. This was thought to be due to synchrotron radiation, caused by the injection of relativistic