You might have heard that at the very center of the Milky Way, a giant black hole lurks around. And a few days ago, a team of astronomers released the very first image of Sagittarius A*, the supermassive black hole at the heart of our galaxy.

It is the very first visual evidence that there is indeed a black hole there. An international team of researchers at the Event Horizon Telescope (EHT) Collaboration got the image. 

The EHT is a combination of telescopes in France, Spain, Greenland, Chile, the United States (Arizona and Hawaii), Mexico, and the South Pole. Together, they work as a "giant" telescope (the size of the Earth!) that can look really far down into distant black holes. Released in 2019, the very first image they got of a black hole was the M87*, in the Messier 87 galaxy, over 53 million light-years from us.

Sagittarius A* deserves the "massive" nickname: it is four million times more massive than our Sun – that is a four followed by six zeroes! But it is still a thousand times smaller and less massive than M87*. So, because of that, taking the snapshot was much harder – even if Sgr A* is much closer to us than M87* (27,000 light-years from Earth). 

As the black hole rotates quite fast and images were different from one another, the team used a set of supercomputers to combine and analyse the data they got – to then get the final picture.

With images like these, not only our technological capacity advances, but also our understanding of how gravity behaves in extreme environments such as black holes. Our knowledge of the Universe certainly advances with it.

Image: Black holes are objects in space where gravity is so strong that not even light can scape from it – and because of that, they do not emit light either. The reddish-orange-yellow ring we see in the image is glowing gas that circles the black hole, which is right at the center of that ring. Credits: EHT Collaboration