A team of scientists may have found the most luminous supernova yet discovered.
At its most intense, the supernova — a huge explosion produced by the last gasps of a massive, dying star — was 570 billion times brighter than the sun, scientists said.
Named ASASSN-15lh, the supernova is thought to belong to a class of objects known as "superluminous supernovas," mysterious objects that shine far more brightly than the average star explosion, though scientists don't yet have an explanation for what could cause these kinds of supernova. The new discovery is detailed in a study published in the journal Science this week.
"ASASSN-15lh is the most powerful supernova discovered in human history," astronomer Subo Dong, co-author of the new study, said in a statement. "The explosion's mechanism and power source remain shrouded in mystery because all known theories meet serious challenges in explaining the immense amount of energy ASASSN-15lh has radiated."
Scientists found the possible supernova in June 2015 using two telescopes in Chile.
ASASSN-15lh is about 3.8 billion light-years from Earth, but it is one of the closest supernovas of this kind yet found, the Kavli Foundation said in the statement.
This supernova is not just brighter than any previously discovered; it is also hotter, and located in a galaxy even larger than the Milky Way, the study suggests.
Many previously discovered superluminous supernovas come from galaxies smaller than our own but produce stars more quickly, perhaps suggesting that the galaxy itself could have something to do with the formation of these superluminous supernovas.
The new study shows that ASASSN-15lh comes from a galaxy larger than the Milky Way, further confusing the already mysterious origin of these objects, though scientists have some ideas about how this supernova could have formed.
It's possible that the supernova may have been caused by the death of a star far more massive than any previously observed or even thought possible, the foundation added.
Before you start worrying that a supernova will suddenly burst forth nearby, sending a boatload of radiation toward Earth, it's important to note that a supernova like this one probably won't threaten the planet "for the rest of its existence," astronomer Robert Quimby told Mashable via email.
But is it really a supernova?
It's also possible that ASASSN-15lh isn't actually a supernova at all.
"I'm not 100% sure this one is even a supernova," Quimby, who was not an author of the study, said. "Other than just being much brighter than anything we have seen before, its spectra are a little different, it doesn't fade away like others have, and its host galaxy is quite different."
While it does seem like this object is likely a supernova, it's also possible that there could be some other explanation for the extreme luminosity.
"There is probably a small chance that it is connected to a star or gas falling into a black hole," Quimby added. "The authors do a good job arguing against this, but I don't think we've cataloged all the unusual things that go bump in the night skies just yet."