The Christmas sky last year was lit up by an extraordinarily powerful and mysteriously long-lasting explosion in space that scientists now suggest was a comet smacking into a dense star or a peculiar supernova death. This strange gamma-ray burst detected on Christmas Day 2010 by NASA’s Swift satellite lasted at least half an hour. Scientists think that shorter gamma-ray bursts are generally caused by merging neutron stars, dead stars made up of super-dense neutron matter. Longer bursts are typically thought to originate from hypernovas, in which giant stars that explode as incredibly powerful supernovas spew two opposing jets of energy as they die, we see them head-on as bursts. However, researchers suspect a number of mysterious events
of completely different origins could mimic gamma-ray bursts. Such might be the case with the Christmas burst, formally known as GRB 101225A. Scientists have two competing explanations for the Christmas burst: a cosmic impact on a dead star in our galaxy, or a peculiar supernova in a distant galaxy. To understand which explanation might be correct, scientists must figure out if the explosion took place in our galaxy or not. Further observations with the Hubble Space Telescope and other observatories could help solve the mystery.