For the first time, astronomers have captured a remarkable image of a supermassive black hole ‘Sagittarius A’ at the heart of our Milky Way galaxy.
- Sagittarius A* is roughly 4.3 million times the mass of our sun and is located about 27,000 light-years away from the Earth.
- Astronomers said the discovery provides overwhelming evidence that the object is indeed a black hole, and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies.
Messier 87 and Sagittarius A*
- The new image comes just over three years after the same astronomers revealed the first ever photograph of a black hole named Messier 87.
- The two black holes bear striking similarities, despite the fact that Sagittarius A* is 2,000 times smaller than Messier 87, which is located in a distant galaxy 55 million light-years away.
- In April 2019, astronomers revealed they had captured an image of a black hole 310 million trillion miles (500 million trillion km) away in a galaxy called M87.
- Messier 87 was described by scientists at the time as ‘a monster’, measuring some 24 billion miles (40 billion km) across — three million times the size of the Earth.
- That was also imaged by the Event Horizon Telescope, a network of eight linked telescopes, showing a glowing ring of red, yellow and white surrounding a dark centre.
What are Black holes ?
- Black holes are regions of space where the pull of gravity is so intense that nothing can escape, including light.
- Therefore the image released depicts not the black hole itself, because it is completely dark, but the glowing gas that encircles the phenomenon in a bright ring of bending light, known as the accretion disc.
- The ring is roughly the size of Mercury’s orbit around the sun, which is about 40 million miles (60 million km) across.
Event Horizon Telescope
- The image were taken by the Event Horizon Telescope.
- The international collaboration that makes up the Event Horizon Telescope effort includes observatories in the South Pole, Europe, South America, Africa, North America, and Australia.
- The project began in 2012 to try to directly observe the immediate environment of a black hole.
What is Even Horizon?
- The event horizon is theoretical boundary around a black hole where not light or other radiation can escape.
- When any of that material gets too close to the edge of the hole, known as the event horizon, its atoms are ripped apart.
What is Sagittarius A*?
- Sagittarius A* owes its name to its detection in the direction of the constellation Sagittarius.
- Its existence has been assumed since 1974, with the detection of an unusual radio source at the centre of the galaxy.
- In the 1990s, astronomers mapped the orbits of the brightest stars near the centre of the Milky Way, confirming the presence of a supermassive compact object there – work that led to the 2020 Nobel Prize in Physics.
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