Hear the melodic singing of a supermassive black hole in the Milky Way… that woke up 200 years ago

10 July 2023, 19:54

Astronomers detect eerie echo in the Milky Way’s galactic centre

By Maddy Shaw Roberts

Scientists believe galactic musical sounds were emitted from the Milky Way’s supermassive black hole at the turn of the 19th century.

The Milky Way has a supermassive black hole at its galactic centre, about 26,000 light years from Earth. Its name is Sagittarius A*, often abbreviated to Sgr A*, and its mass is 4.1 million times that of our sun.

In findings released yesterday, scientists say they noticed an eerie sound coming from the black hole, detected by NASA’s IXPE spacecraft.

Their research indicates this sound, a seemingly melodic singing, is an echo of a violent outburst let out by the black hole at the turn of the 19th century (listen above).

The findings suggest that a mass of gas and dust got too close to the black hole, causing it to wake up from a state of dormancy and devour the materials.

When a black hole feeds on gas and dust, bursts of bright X-ray light bounce and echo, which can then be turned into sound waves.

Hear the melodic singing of a supermassive black hole in the Milky Way… that woke up 200 years ago. Picture: NASA/CXC/SAO/IXPE

The echo was detected after astronomers at France’s Astronomical Strasbourg Observatory noticed that huge clouds of star-forming molecular gas, that live near Sgr A*, were shining brighter in X-rays than usual.

According to observations published on 21 June in the journal Nature, the light was likely not coming from within the gas clouds, but being reflected off them, following an outburst from the black hole.

A team led by Frédéric Marin at the University of Strasbourg has used NASA’s IXPE satellite and found the theory very plausible.

“It reveals the past awakening of this gigantic object – which is four million times more massive than the Sun,” Marin said.

Given the spacecraft can reveal information about how the light was produced and reflected, scientists could deduce that the X-ray’s origins were in the vicinity of Sgr A*, and that they were emitted a little over 200 years ago.

The sonification above, which is an adaptation of NASA’s visual data, shows an curved line ripping across the image, starting at the lower righthand corner. As it passes over the IXPE data, sounds like digital winds are triggered.

“Our work presents the missing piece of evidence that X-rays from the giant molecular clouds are due to reflection of an intense, yet short-lived flare produced at or nearby Sagittarius A*,” Marin added.

We don’t know exactly what got to close to Sagittarius A* as to be ripped apart by its surrounding forces. But we do know it has produced this extraordinary eerie echo, and a huge acoustic cry from the depths of the cosmos.