THE SUPERMASSIVE black hole at the centre of the Milky Way exploded 3.5million years ago, according to astronomers.
This is considered to be ‘astonishingly recent’ in galactic terms and is changing what scientists thought they knew about our galaxy.
This artist’s impression shows the huge bursts of radiation exploding from the centre of the Milky Way and reaching the Magellanic Stream[/caption]
Professor Lisa Kewley, who worked on the study, said: “This is a dramatic event that happened a few million years ago in the Milky Way’s history.
“A massive blast of energy and radiation came right out of the galactic centre and into the surrounding material.
“This shows that the centre of the Milky Way is a much more dynamic place than we had previously thought. It is lucky we’re not residing there!”
The cataclysmic blast ripped through our galaxy and was likely felt 200,00 light years away in the Magellanic Stream.
It is considered to be a recent event because when it happened the dinosaurs had already been wiped out for 63million years and human ancestors were already walking on Earth.
This black hole blast phenomenon is known as a Seyfert flare.
The astronomers think it would have created two enormous ‘ionisation cones’ that would have sliced through the Milky Way.
They think it was caused by nuclear activity in the gigantic black hole, known as Sagittarius A.
It is estimated to have lasted for around 300,000 years, which is extremely short in galactic terms.
Co-author Magda Guglielmo from the University of Sydney said: “These results dramatically change our understanding of the Milky Way.
“We always thought about our Galaxy as an inactive galaxy, with a not so bright centre.
“These new results instead open the possibility of a complete reinterpretation of its evolution and nature.
“The flare event that occurred three million years ago was so powerful that it had consequences on the surrounding of our Galaxy.
“We are the witness to the awakening of the sleeping beauty.”
The research was led by by Professor Joss Bland-Hawthorn from Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D).
During the study, data was gathered by the Hubble Space Telescope and used to calculate when and how the explosion took place.
It will soon be published in The Astrophysical Journal.
What is a black hole? The key facts
Here’s what you need to know…
What is a black hole?
- A black hole is a region of space where absolutely nothing can escape
- That’s because they have extremely strong gravitational effects, which means once something goes into a black hole, it can’t come back out
- They get their name because even light can’t escape once it’s been sucked in – which is why a black hole is completely dark
What is an event horizon?
- There has to be a point at which you’re so close to a black hole you can’t escape
- Otherwise literally everything in the universe would have been sucked into one
- The point at which you can no longer escape from a black hole’s gravitational pull is called the event horizon
- The event horizon varies between different black holes, depending on their mass and size
What is a singularity?
- The gravitational singularity is the very centre of a black hole
- It’s a one-dimensional point that contains an incredibly large mass in an infinitely small space
- At the singularity, space-time curves infinitely and the gravitational pull is infinitely strong
- Conventional laws of physics stop applying at this point
How are black holes created?
- Most black holes are made when a supergiant star dies
- This happens when stars run out of fuel – like hydrogen – to burn, causing the star to collapse
- When this happens, gravity pulls the centre of the star inwards quickly, and collapses into a tiny ball
- It expands and contracts until one final collapse, causing part of the star to collapse inward thanks to gravity, and the rest of the star to explode outwards
- The remaining central ball is extremely dense, and if it’s especially dense, you get a black hole
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