Now, that Event Horizon Telescope has released the image of the Milky Way’s Black Hole, the team will be making movies of these two black holes and looking for other black holes far enough away to study
12 May 2022
By Leah Crane
On 12 May, the Event Horizon Telescope (EHT) revealed the first close-up picture of the black hole at the centre of the Milky Way. Now that it has taken images of both that black hole, called Sagittarius A(Sgr A*), and the one at the centre of the M87 galaxy, known as M87*, it is time for the collaboration behind the images to move on to new scientific pursuits. What’s next?
First, researchers will need to review the data they already have. The images of Sgr Aand M87were both assembled from data gathered in 2017, but there have since been two more observation periods, with extra telescopes added to the collaboration’s original network of eight.
“Data does exist. We have taken data in 2018 with one additional telescope, 2022 with three additional telescopes, and we are working very, very hard to get that to you… as soon as we possibly can, but I can’t make any promises about when,” said EHT researcher Lia Medeiros at the Institute for Advanced Study in New Jersey during a 12 May press event. She said that it will likely take many years for the results to be released.
This work will clarify the structure of Sgr A*’s material, especially the three bright “knots of light” seen in the new photo. The bright spots in the image could be artifacts, given the way it was created. “Those knots tend to line up with the directions in which we have more telescopes,” said EHT researcher Feryal Ozel at the University of Arizona during the press event. “Even though we expect brighter spots in theory, we don’t believe them in our data .”
While the images are consistent with Albert Einstein’s general theory of relativity so far, deeper analysis may give us another check on how that theory might break down in the extreme areas around black holes. Ozel said that the images should hint at something other than how gravity is formulated with general relativity theory right now. “We don’t see any cracks in that theory .”
Finally, another major goal of the EHT collaboration is to make videos of Sgr Aand M87as the material around them moves and changes over time. “We tried to use the data that we got to try to recover a movie,” said EHT researcher Katie Bouman at the California Institute of Technology during the press event. She stated that although they have some data, it is not enough to make movies about black holes.
The additional telescopes that were recently added to the array will help with this. These telescopes will gather data in multiple wavelengths. This will improve the resolution and produce colour images. Images that have been released so far have had colour added to indicate brightness.
So far, these two black holes are the only ones we know of that can be imaged by EHT with high enou