Astronomers do not yet know exactly what they found when studying the ASASSN-15lh object. But whatever it is, before us is the brightest supernova explosion ever recorded in the history of mankind. And maybe one of the strangest.
According to an article published in 2016 in Science, this supernova is located at a distance of 3.8 billion light years from us. It is two or even three times brighter than all supernovae ever recorded in the known universe.
How bright is it? If it were 1000 light-years from Earth, it would be able to destroy our ozone layer. If it were 3,000 light years away, it would be brighter than the full moon in the night sky. And if it were at the other end of our galaxy, it would still be visible even during the day.
So far, scientists do not understand what could have caused such a bright flash, but the most likely culprit for such an event is called a giant star with a powerful magnetic field 10-100 trillion times more powerful than that of the Earth. This is the so-called magnetar, a super-powerful type of neutron star that emits an intense magnetic field.
But there is another strange fact: this incredibly bright supernova in a cloud of exploding gas has practically no traces of hydrogen or helium. Researchers now say there is evidence in the spectrum suggesting the presence of oxygen, but this has yet to be confirmed. As astronomers themselves say, such an anomaly is rather strange, and before that it was practically not observed.
There is another possible reason for this phenomenon: probably, a supermassive black hole in the center of the galaxy where the supernova explosion occurred, came into contact with a very large star and tore it apart, resulting in a colossal explosion. But Todd Thompson, the main author of the published article, believes there are some difficulties here. “ASASSN-15lh is unlike any previously recorded case of the destruction of a star by a black hole. Again, there is no evidence of the presence of hydrogen and helium, which is strange for such a situation."
But then, perhaps, the most interesting thing will begin. To determine what they are dealing with, astronomers will observe the brightness and spectrum of the supernova. And if the brightness does not decrease over time, then, as Thompson says, "then we will be very worried, since in this case the very classification of this event as a supernova will be in question." Thus, then a new explosion, or whatever it may be, will become a completely unique and completely incomprehensible event that has never been recorded in the history of mankind, and science will face a new class of astronomical phenomena that cannot yet be explained.