The the first image of a supermassive black hole in the center of the Milky Way Sagittarius astronomers have just released a star. Technically black holes are invisible. They trap all the light that falls into the trap. Therefore, photography is a kind of paradox. This is actually an image of the shadow of a black hole – a dark circular silhouette set against the background of luminous matter surrounding the black hole.
Astronomers took the picture using a worldwide network of radio observatories called the Event Horizon Telescope or EHT.
EHT uses a method called very long base interferometry, or VLBI. Basically, this means that radio observatories around the world are merging into a single virtual telescope the size of Earth.
This is literally the highest separation technique in all of astronomy. In April 2017, astronomers spent nights simultaneously pointing these telescopes at Sagittarius A * and other supermassive black holes in other galaxies.
It was then that they got the famous photo of a black hole in the center of the galaxy M87, which they published in 2019. M87 is 55 million light-years away and contains a mass of six and a half billion suns.
That’s a lot.
Our black hole, Sagittarius A *, is much smaller but much closer. This is the size of Mercury’s orbit around our Sun and 26,000 light years from Earth. Since Sagittarius A * is smaller than M87, the crushed matter that revolves around it rotates it much faster. This means that the appearance of a black hole is constantly changing.
That’s why it took years to get a clear image of Sagittarius A * from the petabytes of data collected during the 2017 observation.
Think of it as a photograph of a long-time dancer. As the black hole changes faster, it is harder to photograph it. Astronomers say that in the future, if they add more observatories to the EHT, they will even be able to make films about Sagittarius A *.
What would it look like? Video of matter circling the sewers before falling into the abyss.