Our Milky Way’s supermassive black hole has a ‘leak’, NASA scientists have revealed.
The black hole, called Sagittarius A*, periodically emits a ‘blowtorch-like jet’ out into space through this leak, perhaps once every several thousand years, NASA says.
It’s thought the black hole ‘burps out’ this jet every time it swallows something hefty like a gas cloud, and the jet then hits a huge hydrogen cloud.
Sagittarius A* is at the galactic centre of our Milky Way and has a mass that’s 4.1 million times that of our Sun.
The black hole, called Sagittarius A*, periodically emits a ‘blowtorch-like jet’ out into space through this leak, perhaps once every several thousand years, NASA says (artist’s impression)
The new research was led by Professor Gerald Cecil of the University of North Carolina in Chapel Hill, who pieced together multiwavelength observations from a variety of telescopes ‘like a jigsaw puzzle’.
Data was taken from two of NASA’s telescopes – Hubble and Chandra – as well as from ALMA radio telescopes in Chile’s Atacama Desert, and the Very Large Array (VLA) in New Mexico.
Hubble hasn’t photographed the jet yet, which is why it refers to it as a ‘phantom jet’.
But Hubble has helped find evidence that it’s pushing feebly into a huge hydrogen cloud and then splattering, like ‘the narrow stream from a hose aimed into a pile of sand’.
‘Astronomers using the Hubble Space Telescope have captured a glowing cloud of hydrogen near the black hole,’ NASA said.
‘The interpretation is that the cloud is being hit by a narrow, columnated jet of material that was blasted out of the black hole merely 2,000 years ago.
‘This is further evidence that the black hole, with a mass of 4.1 million Suns, is not a sleeping monster but periodically hiccups as stars and gas clouds fall into it.’
Due to their intense gravitational pull, black holes draw material such as gas, plasma, dust and other particles into a swirling, orbiting disc called an ‘accretion disk’.
It’s thought the black hole ‘burps out’ this jet every time it swallows something hefty like a gas cloud, and the jet then hits a huge hydrogen cloud
A schematic based on multiwavelength observations of a suspected jet from Sagittarius A*. The main view shows our galaxy edge-on, with two huge bubbles of plasma glowing in gamma-rays and X-rays. These are evidence for an explosive outburst from the black hole about 2 million years ago. Probing deep into the galaxy’s core (inset), astronomers using Hubble have captured a glowing cloud of hydrogen near the black hole. The cloud is being hit by a narrow, columnated jet of material that was blasted out of the black hole 2,000 years ago
It’s here material that finds itself moving towards the black hole is instead being swept up into the outflowing jets, according to NASA.
The agency describes the jets as narrow ‘searchlight beams’ that are accompanied by a flood of deadly ionising radiation.
When the jet slams into the nearby hydrogen cloud, the outflow scatters into ‘octopus-like tendrils’ that continue along a trajectory out of our galaxy.
‘The streams percolate out of the Milky Way’s dense gas disk,’ said co-author Alex Wagner of Tsukuba University in Japan.
‘The jet diverges from a pencil beam into tendrils, like that of an octopus.’
In the study, Professor Cecil and colleagues ran supercomputer models of jet outflows in a simulated Milky Way disk, which reproduced the observations.
‘Like in archaeology, you dig and dig to find older and older artefacts until you come upon remnants of a grand civilisation,’ he said.
As the jet blows through the hydrogen gas, it hits cosmic material, which creates a series of expanding bubbles that extend out to at least 500 light years.
The streams continue to percolate out of the Milky Way’s dense gas disk into the galactic halo – the large and relatively dust-free spherical region surrounding a spiral galaxy such as our own.
Hubble (pictured) orbits Earth at a speed of about 17,000mph (27,300kph) in low Earth orbit at about 340 miles in altitude
‘Our central black hole clearly surged in luminosity at least 1 million-fold in the last million years,’ said Wagner.
‘That sufficed for a jet to punch into the galactic halo.’
There has already been evidence of jets coming from Sagittarius A* – back in 2013, X-rays detected by Chandra and radio waves detected by VLA revealed a evidence for a ‘stubby’ southern jet near the black hole.
Previous observations by Hubble and other telescopes have also found evidence that the Milky Way’s black hole had an outburst about 2 to 4 million years ago.
This event was energetic enough to create an immense pair of bubbles towering above our galaxy that glow in gamma-rays, first discovered by NASA’s Fermi Gamma-ray Space Telescope in 2010.
The new study has been published in The Astrophysical Journal.