Extract from ABC News
The fastest-growing black hole ever recorded — increasing the equivalent of one sun every day — has been discovered by researchers at the Australian National University (ANU).
The black hole's mass is roughly 17 billion times that of our solar system's Sun, and exists within the brightest currently known thing being continually powered in the universe.
It exists in a quasar — a galaxy that has a supermassive black hole at its centre that actively adds material to itself.
Lead author and ANU Associate Professor, Christian Wolf, said the black hole is indeed creating matter from its environment, and consuming a lot to do so.
"This black hole eats as much mass in a single day as there is in our entire solar system – the Sun and all the planets combined," he said.
"The accretion disk [the holding pattern for all the material waiting to be devoured] is so massive and dense and hot that it starts glowing brightly, and that's the light that we see.
"It's a lot of light that comes out of that accretion disk, about 500 trillion times the amount of light that our Sun emits, or about 20,000 times the amount of light that our entire Milky Way galaxy – with all its billions of stars – emits."
Professor Wolf said the quasar's accretion disk was incredibly big, being seven light years in diameter — 1.5 times the distance from our solar system to the next star in the sky, Alpha Centauri.
The quasar, known as J0529-435, was first detected using a 2.3 metre telescope at the ANU Siding Spring Observatory near Coonabarabran in NSW.
The research team then turned to one of the world's largest telescopes — the European Southern Observatory's Very Large Telescope — to confirm the full nature of the black hole and measure its mass.
"Finding it wasn't easy because … if you look at the sky and you see lots and lots of stars, some of them are actually fast-growing black holes, but you don't know which is which," Professor Wolf said.
"They are in the minority – there's lots of stars out there, very few of them are black holes."
Though very far away, the quasar can be seen from Earth with a backyard telescope with a lens at least the size of a basketball.
It cannot be seen by the naked eye, but given its distance from Earth, Professor Wolf said it's impressive it can be seen with such little work.
"It's very far away, the light has been travelling for 12 billion years to reach us, so evidently it has to be very luminous for us to see it from here," he said.
"And indeed, it's the most luminous object that we now know in the universe.
"All this light comes from the accretion disk, which is a giant storm cell — a storm cell with seven light years of diameter, and with material on the outside that moves at wind speeds of a few thousand kilometres per second."
The scientific community's understanding of black holes is quite limited, with nothing known about what is inside one.
"Physicists describe black holes as entities that only have two properties: mass and rotation," Professor Wolf said.
"Mass and rotation are the only things we can possibly measure — everything else is unknown.
"What's inside, it doesn't show in any way."
ANU astrophysicist and former vice-chancellor, Brian Schmidt, said the "quite remarkable" discovery was significant for expanding our understanding of black holes.
"I think the reason this is mind blowing is just the fact that the thing exists at all," he said.
"It is not something I would've thought would have been in the universe, it just seems too big and too active.
"But it'll be a great laboratory to figure out what's going on with black holes, because there are a lot of mysteries about why there are so many — and so many that are big — in the universe."
The authors of the research paper suggested the black hole at the centre of quasar J0529-435 was amassing near to the Eddington limit — the proposed upper limit to the mass of a star or an accretion disk.
But to know for sure whether that is the case further research and observations will be needed to explore its growth rate.
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