The neutron star (red sphere) with its strong magnetic field (white lines) spins around itself nearly 30 times per second injecting energetic electrons in the space region around it in this artist's rendition released on January 13, 2016. The green and blue shaded regions depict different particle acceleration zones from where the detected photons could originate. The green zone lies in the vicinity of the pulsar's magnetosphere, whereas the blue zone could be as far as 100,000 km away from the pulsar. The massive supernova is about 3.8 billion light-years away in a galaxy roughly three times the size of the Milky Way, scientists wrote in a report in this week's issue of the journal Science. REUTERS/Patricia CarcelÃ©n Marco/Handout via Reuters ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. IT IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS. EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. NO RESALES. NO ARCHIVE. MANDATORY CREDIT

The explosion was 570 billion times brighter than the sun and 20 times brighter than all the stars in the Milky Way galaxy combined, according to a statement from The Ohio State University, which is leading the study. Scientists are straining to define its strength.

“This may be the most powerful supernova ever seen by anybody … it’s really pushing the envelope on what is possible,” study co-author Krzysztof Stanek, an astronomer at Ohio State, was quoted as saying in The Los Angeles Times.

The team of astronomers released their findings this week in the journal Science. The explosion and a gas cloud that resulted are called ASASSN-15lh after the team of astronomers, All Sky Automated Survey for Supernovae, that discovered it last June.

A supernova is a rare and often dramatic phenomenon that involves the explosion of most of the material within a star. Supernovas can be very bright for a short time and usually release huge amounts of energy.

Searching for the power source

This blast created a massive ball of hot gas that the astronomers are studying through telescopes around the world, Ohio State said. It cannot be seen with the naked eye because it is 3.8 billion light years from Earth.

There’s an object about 10 miles across in the middle of the ball of gas that astronomers are trying to define.

“The honest answer is at this point that we do not know what could be the power source for ASASSN-15lh,” said Subo Dong, lead author of the Science paper, according to Ohio State. He is a Youth Qianren Research Professor of astronomy at the Kavli Institute for Astronomy and Astrophysics at Peking University.

Todd Thompson, professor of astronomy at Ohio State, said the object in the center may be a rare type of star called a millisecond magnetar. Spawned by a supernova, it’s a rapidly spinning, dense star with a powerful magnetic field.

Could it be a ‘supermassive black hole’?

To achieve the brightness recorded, the magnetar would have to spin 1,000 times a second and “convert all that rotational energy to light with nearly 100% efficiency,” Thompson said, according to the Ohio State press release. “It would be the most extreme example of a magnetar that scientists believe to be physically possible.”

The question of whether a suprnova truly caused the space explosion may be settled later this year with help from the Hubble Space Telescope, which will allow astronomers to see the host galaxy surrounding the object in center of the ball of gas, Ohio State said.

If it’s not a magnetar, it may be unusual nuclear activity around “a supermassive black hole,” Ohio State said.