NASA's Hubble spots a mysterious flash in the middle of nowhere that defies science

• A blinding burst of blue light flashing from seemingly empty space is puzzling astronomers.
• Scientists had previously thought Luminous Fast Blue Optical Transients were caused by dying stars.

A bright flash of blue light appearing in the middle of seemingly empty space has scientists confused.

The brilliant flash — thought to have burned at about 36,000 degrees Fahrenheit —is a rare explosion known as a Luminous Fast Blue Optical Transient (LFBOT). These are some of the brightest and most unpredictable known visible-light events in the universe, NASA said in a statement about the findings Thursday.

Scientists previously thought they knew what could cause such a bright burst of energy. But the latest observation, first spotted in April this year, is causing them to rethink what may be happening.

"The more we learn about LFBOTs, the more they surprise us," Ashley Chrimes, an author on a paper about the discoveries and European Space Agency Research Fellow, said in the press release.

A bright flash where it shouldn't be

Because these flashes are so brilliant and short-lived — LFBOTs turn off in a matter of days — scientists had previously concluded they must be caused by a specific type of event called a core-collapse supernova.

Supernovae usually shine for months. By contrast, core-collapse supernovae, which occur at the death of the biggest of stars, release a burst of energy that only lasts a few days, which is in line with what was being seen during an LFBOT, per the press release.

The problem is that this latest LFBOT, nicknamed the "Finch," happened 15,000 light years from the nearest galaxy. That's much too far for a core-collapse supernova to travel.

Supernovae come from stars, which are born inside galaxies. Because big stars don't live long, it's very unlikely a star that big would have had the time to travel that far before bursting into a core-collapse supernova, per the press release.

"We've now shown that LFBOTs can occur a long way from the center of the nearest galaxy, and the location of the Finch is not what we expect for any kind of supernova," said Chrimes in the press release.

An unidentified black hole or two traveling stars crashing?

So it's back to the drawing board to try to understand what is causing the LFBOTs.

There are a few more hypotheses for what could cause the bright blue flashes. But they are a bit weirder.

One possibility is a black hole is swallowing up stars. In that case, you'd expect to see a globular cluster of stars around it, which hasn't been spotted yet. But it may be the case that the telescopes pointed at the area so far aren't powerful enough. The new James Webb Space Telescope, with its extended capabilities, could provide more answers, per the press release.

Another possibility is that two rogue neutron stars have been traveling through space at breakneck speeds, and they happened to crash into each other creating a kilonova, an explosion 1,000 times more powerful than a standard nova.

"The discovery poses many more questions than it answers," said Chrimes in the press release. "More work is needed to figure out which of the many possible explanations is the right one."

The findings were shared ahead of publication on a pre-print server and are expected to be published in the peer-reviewed journal The Monthly Notices of the Royal Astronomical Society shortly.