STRANGER THAN FICTION: WHAT WE KNOW (AND DON’T KNOW) ABOUT BLACK HOLES
Naomi Dinmore explains what current research can tell us about black holes and what is yet to be discovered.
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lack holes – staggeringly huge, monstrously dense objects in space that devour anything and everything in their paths. Terrifying. Their existence was first predicted by Einstein in his Theory of General Relativity and have since been proven to exist thanks to the efforts of many scientists across the globe. Black holes have fascinated many from when they were first hypothesised. No wonder they are used so heavily in science fiction.
formed from stars over 100x the mass of our sun, and supermassive black holes are formed when monstrous stars, millions of times the sun’s mass, collapse and die. It is thought that there is a supermassive black hole at the centre of our galaxy. There are also primordial black holes, which are thought to have formed straight after the big bang at the beginning of the universe’s formation.
But how much do we actually know about black holes? And how much is just fiction?
…if there are other types. Stephen Hawking theorised that mini black holes existed, with mass much smaller than the mass of our sun. If they did exist, their existence would be extremely short-lived, and nobody has yet managed to observe or create one.
We know… …how they form. Black holes are formed when a dying star, many times greater than the mass of our sun, collapses under its own immense gravity, concentrating all its mass into a miniscule point. Stellar black holes are formed from stars over 5x the mass of our sun, intermediate black holes a r e
We don’t know…
We know… …how they die (ish). In 1971, theoretical physicist Stephen Hawking came up with the concept of Hawking Radiation. He predicted that black holes emit streams of energy in the form of waves and particles, gradually reducing its mass, and essentially evaporating the black hole. In 2019, Physicists managed to simulate the effects of a black hole and show that this radiation was emitted. We don’t know… ...this for sure. At the moment, Hawking Radiation is still just a prediction. We know… …what they look like. In 2019, with the help of computer scientist Dr. Katie Bouman and a huge international effort, scientists managed to take a photo of a black hole,
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using many different telescopes around the Earth to effectively make one giant telescope. They obtained a picture of the shadow of the supermassive black hole at the centre of the M87 galaxy. It is 6.5 million times the mass of our sun and over 55 million light years from Earth.
Black holes are formed when a dying star, many times greater than the mass of our sun, collapses under its own immense gravity, concentrating all its mass into a miniscule point. We don’t know… …what they look like. Amazing as this image is, a black hole has such immense gravity that no light can escape its pull. The point after which we cannot see is known as the Event Horizon. The speed required to escape this boundary is greater than the speed of light, which is, as far as we know, the upper limit for the speed of any matter or energy in the universe. Because we require light to see things, what a black hole looks like beyond its Event Horizon is still a mystery.
