A MYSTERIOUS burst of light appears to have been emitted by the supermassive black hole at the heart of our galaxy.
Space scientists recorded a large burst of infrared radiation coming from Sagittarius A* – leaving them baffled.
Experts say the burst was brighter than anything ever produced by this particular black hole.
That’s impressive because Sagittarius A* is one of the best-documented black holes, thanks to its central location within the Milky Way galaxy.
The team that spotted that strange “glowing” have been studying Sagittarius A* for 20 years.
But they were shocked to record a 75-times increase in infrared light in May.
“I was pretty surprised at first and then very excited,” said Tuan Do, an astronomer at the University of California, speaking to ScienceAlert.
“The black hole was so bright I at first mistook it for the star S0-2, because I had never seen Sgr A* that bright.
“Over the next few frames though, it was clear the source was variable and had to be the black hole.
“I knew almost right away there was probably something interesting going on with the black hole.”
The problem is that astronomers aren’t exactly sure why the black hole appeared to give off huge amounts of light.
Investigations are ongoing to determine the exact source of the “glow”.
The flash was spotted during four nights of observations at the WM Keck Observatory in Hawaii.
The mysterious brightening was captured on May 13, revealed in a timelapse of a two-hour period squashed to just a few seconds.
In the video, it’s possible to see a brightly glowing dot at the beginning.
This is dust and gas swirling around the black hole.
Black holes don’t emit any radiation that can be detect by current equipment, but matter nearby does.
That’s because they’re under immense gravitational forces that create a friction effect – producing radiation.
When astronomers use a telescope in the infrared range, it’s possible to see this radiation as brightness.
Normally the brightness of Sagittarius A* will flicker a little – but scientists have never seen it flash as brightly as it did on May 13.
What is a black hole? The key facts
Here's what you need to know…
What is a black hole?
- A black hole is a region of space where absolutely nothing can escape
- That’s because they have extremely strong gravitational effects, which means once something goes into a black hole, it can’t come back out
- They get their name because even light can’t escape once it’s been sucked in – which is why a black hole is completely dark
What is an event horizon?
- There has to be a point at which you’re so close to a black hole you can’t escape
- Otherwise literally everything in the universe would have been sucked into one
- The point at which you can no longer escape from a black hole’s gravitational pull is called the event horizon
- The event horizon varies between different black holes, depending on their mass and size
What is a singularity?
- The gravitational singularity is the very centre of a black hole
- It’s a one-dimensional point that contains an incredibly large mass in an infinitely small space
- At the singularity, space-time curves infinitely and the gravitational pull is infinitely strong
- Conventional laws of physics stop applying at this point
How are black holes created?
- Most black holes are made when a supergiant star dies
- This happens when stars run out of fuel – like hydrogen – to burn, causing the star to collapse
- When this happens, gravity pulls the centre of the star inwards quickly, and collapses into a tiny ball
- It expands and contracts until one final collapse, causing part of the star to collapse inward thanks to gravity, and the rest of the star to explode outwards
- The remaining central ball is extremely dense, and if it’s especially dense, you get a black hole
One possible theory is that a gas cloud named G2 approached within 36 light-hours of the black hole in 2014.
Scientists believe that the black hole’s May event may have been a delayed reaction to the gas cloud being torn to shreds.
An alternative theory is that it relates to an object called S0-2 – a star that orbits the black hole every 16 years.
Last year S0-2 made its cloest approach, coming within just 17 light-hours of the black hole.
“One of the possibilities is that the star S0-2, when it passed close to the black hole last year, changed the way gas glows into the black hole,” Do told ScienceAlert.
“And so more gas is falling on it, leading it to become more variable.”
A paper detailing the probable cause of the flash is expected to be published in the Astrophysical Journal Letters later this year.
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Huge black hole at centre of our galaxy mysteriously ‘glows’ in eerie video – and scientists are completely baffled