Researchers observe mysterious radiation emanating from black hole

Researchers observe mysterious radiation emanating from black hole at the center of our galaxy for the first time

  • Scientists captured a radiation flash from a black hole inside our galaxy
  • Imagery shows Sagittarius A growing 75 times brighter than normal in May  
  • Experts aren’t sure what caused the flash but say it may be due to a nearby star 
  • Findings will be  in an upcoming paper in The Astrophysical Journal Letters

Scientists say they have recorded a mysterious and unprecedented flash of radiation emanating from the black hole at the center of our galaxy. 

According to researchers from the University of California Los Angeles, UCLA, Sagittarius A*, a supermassive black hole that is 4 million times the mass of our sun, shot out a flash of radiation in May that is larger than anything ever witnessed. 

The sudden blast of brightness caused the black hole to grow 75 times brighter than usual levels, before returning to normal according to the scientists. 

A burst of radiation has captured the attention of astronomers observing a supper massive black hole at the center of our galaxy.

‘I was pretty surprised at first and then very excited,’ astronomer Tuan Do of the UCLA told ScienceAlert in a statement.

‘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 phenomenon was captured by scientists using the WM Keck Observatory in Hawaii and was recorded over a four night period.

In a video from the scientists, the flash, which lasted for more than two hours, is reduced to just a few seconds via a time-lapse. 

Researchers say, though the event much brighter than any other observed in human history, it may have been even brighter than the data lets on since its peak brightness was captured at the start of the telescope’s imaging.

‘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!,’ said Do in a tweet.

While black holes regularly flicker, fluctuating slightly in brightness from moment to moment, large flashes like the one observed by scientists in May indicate that a larger object has been caught up by the black hole’s gravitational pull.

Scientists say they weren’t aware of anything travelling close enough to create that kind of friction, however. 

According to the researchers, the sudden flash is as mysterious as it is anomalous, but they hypothesize that it could be spurred by the close approach of a star called S0-2.  

The flash is seen above next to other objects in our galaxy and is shown coming close to a star dubbed SO-2

‘One of the possibilities is that the star S0-2, when it passed close to the black hole last year, changed the way gas flows into the black hole, and so more gas is falling on it, leading it to become more variable,’ Do told ScienceAlert.

SO-2 began to make its closet approach last year and came 17 light-years away from Sagittarius A. 

As researchers pore over more data for answers, another teams like those at the Atacama Large Millimeter/submillimeter Array, ALMA, will also take a look as their telescopes were also observing the black hole throughout the last several months.

The findings of the phenomenon will be published in a yet-to-be-release paper in The Astrophysical Journal Letters and is now available on pre-print journal ArXiv.


The Galactic centre of the Milky Way is dominated by one resident, the supermassive black hole known as Sagittarius A* (Sgr A*).

Supermassive black holes are incredibly dense areas in the centre of galaxies with masses that can be billions of times that of the sun.

They act as intense sources of gravity which hoover up dust and gas around them. 

Evidence of a black hole at the centre of our galaxy was first presented by physicist Karl Jansky in 1931, when he discovered radio waves coming from the region. 

Pre-eminent yet invisible, Sgr A* has the mass equivalent to some four million suns.  

At just 26,000 light years from Earth, Sgr A* is one of very few black holes in the universe where we can actually witness the flow of matter nearby.

Less than one per cent of the material initially within the black hole’s gravitational influence reaches the event horizon, or point of no return, because much of it is ejected. 

Consequently, the X-ray emission from material near Sgr A* is remarkably faint, like that of most of the giant black holes in galaxies in the nearby universe.

The captured material needs to lose heat and angular momentum before being able to plunge into the black hole. The ejection of matter allows this loss to occur.

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