A star being eaten by a black hole could explain a supernova brighter than 20 Milky Ways

THERE’s a dark explanation behind the biggest supernova ever seen. Last year, ASASSN-15lh flared brighter than 20 Milky Ways. Turns out it was being eaten alive.

An artist’s impression of the burning remains of a star being whirled around a spinning black hole. Such an event could explain the extraordinary brightness of a supernova seen last year. Picture: ESO/M. Kornmesser

THERE’s a dark, sinister explanation behind the brightest supernova ever seen. Last year, ASASSN-15lh flared up to 20 times brighter than the entire Milky Way. Turns out it was being eaten alive.

All Sky Automated Survey for SuperNovae (ASAS-SN) last year observed the brightest supernova ever recorded. In fact, its intensity of 570 billion suns was twice as bright as the previous brightest.

The problem was, nobody knew how it could be possible.

A supernova is when a burnt-out star collapses under its own weight, producing a tremendous shockwave that blasts its superheated surface layers into deep space.

But no known star operated on the scale necessary to produce a supernova as bright as ASASSN-15lh.

A new study published in the journal Nature Astronomy has come up with an alternative explanation.

It wasn’t a supernova the survey had seen.

Flare from the most luminous SN ever or a black hole devouring a nearby star? New evidence points towards the latter https://t.co/zvbj5KwtpC pic.twitter.com/Fr6E2an01y

— Nature Astronomy (@NatureAstronomy) December 12, 2016

“We observed the source for 10 months following the event and have concluded that the explanation is unlikely to lie with an extraordinarily bright supernova,” project leader Giorgos Leloudas said in a statement.

“Our results indicate that the event was probably caused by a rapidly spinning supermassive black hole as it destroyed a low-mass star.”

It’s only the 10th time such an event has been observed.

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The titanic forces that tore the star apart unleashed far more than just its outer layers. It was disembowelment on a cosmic scale.

The process is explained as being a tidal disruption, where the gravity of a rapidly spinning black hole shreds a star — tearing off a whirling mass of component parts which collide and explode.

The enormous heat generated by the star’s death throes produces an intense burst of light.

The blast from ASASSN-15lh poses no threat to Earth. It occurred in a galaxy some four billion light years away.