Our Galaxy's Black Hole Suddenly Lit Up And It's Not Clear Why
In the middle of our Milky Way sits a black hole... it's actually a 'supermassive black hole'. Impressive, huh?
Well, you might not be as impressed when you find out that it erupted back in May 2019 and not a soul can explain why it happened. But don't worry, we're all safe, given that the black hole is 26,000 light years away.
The hole - which is also referred to as Sagittarius A*, or Sgr A* for short - emitted what is said to have been a large burst of infrared radiation and became 75 times brighter than usual.
Here's a timelapse of images over 2.5 hr from May from @keckobservatory of the supermassive black hole Sgr A*. The black hole is always variable, but this was the brightest we've seen in the infrared so far. It was probably even brighter before we started observing that night! pic.twitter.com/MwXioZ7twV
- Tuan Do (@quantumpenguin) August 11, 2019
Astronomer Tuan Do, who is part of a team studying Sgr A* at the University of California Los Angeles, said that the flash could be the result of another star passing close by. Another theory is that the light was caused by G2, a gas cloud known to have passed close to the black hole five years ago.
Do told ScienceAlert: "I was pretty surprised at first and then very excited.
"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.
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"I knew almost right away there was probably something interesting going on with the black hole."
2/ To be clear: This black hole is 26,000 light years away - that's 260 quadrillion km! - and behind a vast amount of dust, so it took a huge telescope to see it at all. We're in no danger from this.
- Phil Plait (@BadAstronomer) August 13, 2019
Phil Plait, an American astronomer who also runs a blog, tweeted to explain that he isn't sure what caused the bright eruption but, like Tuan, puts it down to a number of possibilities, including a passing star and also a cloud of dust.
He added: "Or it was something else entirely. It's hard to observe the black hole, because the dust between us and it covers a multitude of its sins. Also, the Sun passes this part of the sky making it unobservable for months at a time starting in the late fall."
He also wrote: "I know it doesn't look like much, but that's MATTER FALLING INTO A GINORMOUS BLACK HOLE AND BLASTING OUT THOUSANDS OF TIMES THE ENERGY OF THE SUN. Seen from HUNDREDS OF THOUSANDS OF TRILLIONS OF KILOMETERS AWAY. So, *yeah*.
"Sometimes I wish stuff were closer so we could see it better, and sometimes I'm glad it's really far away. This is a little of both."
Featured Image Credit: Sophie Dagnello NRAO/AUI/NSF; NASA, STScI