The nearest supermassive black hole to Earth is glowing strangely and we don’t know why

 A simulated image of the black hole lurking at the dark heart of the Milky Way

The one thing most people know about black holes is that they’re dark objects which lurk ominously rather than twinkle cheerfully. But the closest supermassive hole to Planet Earth has bucked that trend and has been observed glowing more brightly than at any other point in its recorded history. Black holes are so dense that not even light can travel fast enough to escape their mighty maws.

However, the greedy monsters can also produce an eerie glow in the right circumstances. For instance, black holes are often surrounded by an ‘accretion disc’ of gas and other material which shines brightly due to the forces of friction and gravity. This phenomenon is what allowed astronomers to take the first-ever picture of a black hole earlier this year, which showed a bright accretion disc surrounding a dark core.

Now a team from the University of California have spotted Sagittarius A* – the supermassive hole at the center of humanity’s home galaxy – shining 75 times brighter than usual. You can see footage of the phenomenon in the tweet below.

The behavior cannot yet be fully explained, so scientists are currently racing to understand why the supermassive mega-beast is glowing so brightly. It’s likely that the change is caused by an increase in the amount of gas being sucked into the black hole. A star called S0-2 passed by Sagittarius A* in 2018 and may have caused a reaction which sent more gas gushing into the hole.

‘The brightness variations are likely related to the amount of gas that falls into the black hole,’ tweeted astronomer Tuan Do, lead author of a paper on the hole’s strange glow. ‘The big question we have is whether this increased activity means the there is something going on that is changing the gas flow and if so, how long this will last?’

This is the Milky Way, the galaxy our species calls home

There are several other possibilities which could explain the celestial light show – including the possibility that everything we thought we knew about black holes is wrong. ‘Another possibility is that gas from the object G2 which went through closest approach in 2014 took a while to get to the black hole,’ Do added. ‘Maybe our models need to be updated. We don’t have enough data yet for a firm physical explanation. Stay tuned!