Scientists have spotted a superluminous cosmic explosion that is so massive it would outshine every single star in the Milky Way galaxy combined.

Called ASASSN-15lh, it is billions of light years away and produces radiated energy that is an eye-popping 570 billion times more powerful than our sun, according to a Forbes report.

This massive supernova is twice as bright as the previous record holder for brightest supernova, and scientists are trying to figure out what caused it.

Subo Dong, who is Youth Qianren Research Professor at the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University, said in a statement that it’s the most powerful supernova observed in the history of mankind, but the cause and the power source behind this incredible event “remain shrouded in mystery” as all known theories don’t seem to adequately explain this phenomenon.

Scientists have put forward a number of possibilities, one being that this was a rare type of star called a magnetar, which is a rapidly spinning neutron star that has such incredible power that it begins to push at the boundaries of physics. But even that isn’t powerful enough to explain this massive explosion, so scientists will be studying it carefully to come up with alternative possibilities.

The news release is below:

In a new study, researchers describe the most luminous supernova yet observed, which resides in an unusual host galaxy. The discovery will provide important insights into super-luminous supernovae (SLSNe) and how they affect their host galaxies. SLSNe were first identified less than two decades ago and little is known about these exceptionally bright exploding stars. The new, record-breaking supernova was discovered last June using the All-Sky Automated Survey for SuperNovae system. According to analysis by Subo Dong et al., this super-luminous supernova, which they dubbed ASASSN-15lh, outshines all other supernovae currently published in the literature by at least a factor of two. Also intriguing is the location of ASASSN-15lh: although most SLSNe occur in small, but “busy” star-forming galaxies, ASASSN-15lh exploded in a large and rather calm galaxy. The authors note that ASASSN-15lh’s behavior mimics the temperature and luminosity phases of hydrogen-poor SLSNe, yet exhibiting much greater extremes. Without hydrogen, the authors speculate that the extraordinary emission of luminosity by ASASSN-15lh may be powered by a staggering amount of decaying nickel (at roughly 30 times the mass of the sun), or perhaps a rapidly rotating, highly magnetic neutron star. Further exploration of ASASSN-15lh could shed new light on the mysterious nature of SLSNe.