An international team of astronomers has captured the first image of a supermassive black hole at the center of our own Milky Way Galaxy.
The image, produced by a global team of scientists known as the Event Horizon Telescope (EHT) Collaboration, is the first direct visual confirmation of the presence of this invisible object, coming three years after the first-ever image of a black hole. from a distant galaxy.
“For decades, we’ve known about a compact object at the heart of our galaxy that is four million times more massive than our sun,” said Harvard University astronomer Dr Sara Issaoun.
“Today, right now, we have direct evidence that this object is a black hole.”
The image does not show the black hole itself – because it is completely dark – but the glowing ultra-hot plasma* and gas that surrounds the phenomenon* in a bright ring-like structure.
This glowing halo* swirls around the black hole’s boundary beyond which nothing, not even light, can escape its gravitational pull*.
dr. Issaoun said the black hole from Earth would be about the size of a donut on the moon’s surface.
EHT project scientist Geoffrey Bower, of Taiwan’s Academia Sinica, said: “These unprecedented* observations have vastly improved our understanding of what’s happening at the center of our galaxy.”
The black hole has been given the name Sagittarius A* (pronounced A-star), or Sgr A* for short, because it was detected in the direction of the constellation Sagittarius.
Located 27,000 light-years from Earth, it’s been believed to have existed since 1974 when an unusual radio source was detected in the center of the galaxy.
In the 1990s, astronomers mapped the orbits of the brightest stars near the center of the Milky Way and confirmed the presence of a supermassive compact object there, work leading to the Nobel Prize in Physics in 2020.
Although the presence of a black hole was thought to be the only plausible* explanation, the new image provides the first direct visual evidence.
To capture images of such a distant object, eight giant radio observatories across the planet had to be linked together to form a single Earth-sized virtual telescope called the EHT.
“The EHT can see three million times sharper than the human eye,” says German scientist Thomas Krichbaum of the Max Planck Institute for Radio Astronomy.
“So if you’re sitting in a beer garden in Munich (in Germany) for example, you can see the bubbles in a glass of beer in New York (in the US).”
The EHT stared at Sgr A* for several nights in a row, an idea akin to long-exposure photography and the same process used to create the first image of a black hole, released in 2019. That black hole is called. M87* because it is located in the Messier 87 galaxy.
The M87* and Sgr A* are similar, although Sgr A* is 2000 times smaller than M87*.
“Close to the edge of these black holes, they look astonishingly similar,” said Sera Markoff, co-chair of the EHT Science Council and professor at the University of Amsterdam.
Both black holes behaved as predicted by German-born physicist Albert Einstein in his 1915 general theory of relativity. His theory was that gravity is not an invisible force that pulls objects together, but a curvature or warping* of space. The more massive an object, the more it distorts the space around it.
The image of Sgr A* is the result of the work of more than 300 researchers in 80 countries over a five-year period. Their research was published in The Astrophysical Journal Letters.
- plasma: an electrically charged gas
- phenomenon: something that is seen to exist or to happen, but which is difficult to explain
- halo: circle of light
- gravity: when gravity contracts objects
- unmatched: never done, seen or known before
- Zodiac sign: group of stars forming a recognizable pattern
- plausible: can be believed, seems likely to be true
- warp: get bent or twisted out of shape
- By what name is the global team of scientists known?
- How many times bigger than our sun is the Sgr A* black hole?
- Why was the black hole called Sagittarius A* or Sgr A* for short?
- What is the name of the first black hole that scientists have photographed?
- Who invented the general theory of relativity?
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