Scientists have detected the highest-energy "ghost particle" ever seen. The particle, a type of neutrino, arrived at Earth at nearly the speed of light and with 30 times the energy of the previous most energetic neutrino ever glimpsed. This is the first solid evidence that neutrinos with such high energies can be produced in the universe.
This particle's high-energy nature indicates that the neutrino originates from outside the Milky Way, and though the ghost particle's source is yet to be determined, the team has 12 suspects in mind. The suspects are all "blazars," or the energetic cores of "active galactic nuclei" (AGN) that are powered by feeding supermassive black holes. Blazars are types of quasars that stand out because the beams of high-energy particles and light they blast out are pointed directly at Earth.
Another possibility, however, is that the high-energy neutrino was created when an ultramassive cosmic ray particle slammed into particles of light, or "photons," left in the universe after some event that occurred just after the Big Bang.
