Scientists observe ‘flattest’ explosion ever seen in space – study

An explosion the size of our solar system has baffled scientists, as its shape – similar to that of an extremely flat disc – challenges everything they know about explosions in space.

Astronomers observed the explosion 180 million light years away, and they say it is much flatter than ever thought possible.

Explosions are usually expected to be spherical just like the stars themselves, but this one is the flattest ever seen.

The study reports that the explosion was an extremely rare Fast Blue Optical Transient (FBOT) – known colloquially amongst astronomers as “the cow”.

Only four others have ever been seen, and while scientists do not know how they occur, researchers suggest the new discovery has helped solve part of the puzzle.

According to the study, a potential explanation for how this explosion occurred is that the star itself may have been surrounded by a dense disk, or it may have been a failed supernova (the massive explosion at the end of the life of some stars).

How FBOT explosions occur is still a mystery, but it is hoped the observations, published in Monthly Notices of the Royal Astronomical Society will help answer some of the questions.

Dr Justyn Maund, lead author of the study from the University of Sheffield’s Department of Physics and Astronomy, said: “Very little is known about FBOT explosions – they just don’t behave like exploding stars should, they are too bright and they evolve too quickly.

“Put simply, they are weird, and this new observation makes them even weirder.

“Hopefully, this new finding will help us shed a bit more light on them – we never thought that explosions could be this aspherical.

“There are a few potential explanations for it: the stars involved may have created a disc just before they died, or these could be failed supernovas, where the core of the star collapses to a blackhole or neutron star which then eats the rest of the star.

“What we now know for sure is that the levels of asymmetry recorded are a key part of understanding these mysterious explosions, and it challenges our preconceptions of how stars might explode in the universe.”

Scientists made the discovery after spotting a flash of a specific wave of light called polarised light completely by chance.

The used the Liverpool Telescope located on La Palma, in the Canary Islands, to analyse the light, allowing them to measure the shape of the explosion, effectively seeing something the size of our solar system but in a galaxy 180 million light years away.

The experts used the data to reconstruct the 3D shape of the explosion, and were able to map the edges of the blast – allowing them to see just how flat it was.

The mirror of the Liverpool Telescope is only 2.0 metres in diameter but, by studying the polarisation, the astronomers were able to reconstruct the shape of the explosion as if the telescope had a diameter of 625 kilometres.