Milky Way’s ‘quiet wimpy’ black hole is getting hungrier and brighter

Milk Way galaxy's black hole, Sagittarius A*, captured by NASA's Chandra X-Ray ObservatoryNASA


  • The big spark from the black hole at the heart of the Milky Way in May was only one of three ‘unprecedented' changes.
  • The black hole, Sagittarius A*, is the hungriest its been in the past 24 years — normally known for being quite benign.
  • Scientists are yet to determine the cause behind the black hole's increase in appetite but they do have a few theories running.
The black hole at the center of our galaxy, the Milky Way, is normally benign. But, for the first time in 24 years, it's feasting on everything that comes its way.

It's hungrier than ever before, consuming unusually large amounts of dust and gas — and researchers at the University of California Los Angeles ( UCLA) are trying to figure out why.

"It's usually a pretty quiet, wimpy black hole on a diet. We don't know what is driving this big feast," said Andrea Ghez, co-author of the study published in Astrophysical Journal Letters.

One of the changes they observed was when the black shone 75 times brighter than usual on May 13. But that wasn't the only time. There were also two other nights this year when the team observed "unprecedented" changes in the black hole, according to Ghez.

Hungry hungry black hole

Something was already up with Sagittarius A* when it shone brighter than ever before. Now, its unusual appetite has researchers thinking that the black hole might be entering a new phase altogether.

Artist concept of a growing black hole, or quasar, seen at the center of a faraway galaxyNASA

On the other hand, it could just be an unusual form of gas that's making the black hole react this way.

"We have never seen anything like this in the 24 years we have studied the supermassive black hole," stated Ghez.

Artist concept of matter swirling around a black holeNASA

Researchers from the UCLA Galactic Centre Group looked at more than 13,000 observations of the Milky Way's black hole from the Keck Observatory in Hawaii and the European Southern Observatory's Very Large Telescope in Chile.

These observations covered 133 nights since 2003.

‘Unprecedented' changes in the black hole

If the black hole isn't changing and it's only an unusual amount of gas and dust — the scientists currently have three possible explanations.

One reason for the black hole's massive brightness could be the star S0-2. When it approached the black hole in 2018, a large quantity of its gas could have been pulled towards it, which only reached the black hole this year.

Rendering of a star called S0-2 orbiting the supermassive black hole at the center of the Milky WayNational Science Foundation

The other theory is that a set of binary stars called G2 could be the cause of the black hole's unusual appetite. Their closest approach to the black hole was five years ago but its far reaching effects, could have stripped G2 of its outer layer.

If it's not stars, it could be asteroids. If a large enough asteroid was caught in the black hole's gravity, it's possible that it could be the cause of its large meal.

Either way, it's nothing that Earth has to worry about. The black hole is a massive 26,000 light years away from the planet and poses no immediate threat. In order for there to be repercussions, the brightness would have to be 10 billion times as bright than what was observed, to affect life on Earth.

See also:
There was a big spark — 75 times brighter than usual — from the black hole at the heart of the Milky Way

Hubble has found a black hole disk that should be non-existent

Black hole or a neutron star — NASA puzzled over strange bright lights in the 'Fireworks' galaxy
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