If everything goes to plan, we should be getting our first image of a black hole sometime within a year.
Yesterday, scientists “switched on” a global array of telescopes with the goal of imaging the supermassive black hole 26,000 light-years away at the center of our galaxy, Sagittarius A* (Sgr A*). The project, called the Event Horizon Telescope (EHT), is running from April 5 to April 14, with the first results expected later this year or early in 2018.
“These are the observations that will help us to sort through all the wild theories about black holes. And there are many wild theories,” Gopal Narayanan at the University of Massachusetts Amherst, involved in the project, said in astatement. “With data from this project, we will understand things about black holes that we have never understood before.”
While we’re fairly certain black holes exist, we’ve never actually seen one. But we can infer their existence from their effect on stars and galaxies. At the center of our galaxy, for example, stars seem to be orbiting an unseen object. Elsewhere, we’ve seen intense amounts of X-rays and large jets of material believed to have originated from black holes.
But while they can be millions to billions of times more massive than our Sun, some – like Sgr A* – are only a few times bigger in radius. Sgr A* is about 30 times bigger in size to be exact. This makes them incredibly difficult to see, sort of like trying to image a grapefruit on the Moon according to Narayanan.
That’s where the EHT comes in. More than 10 telescopes around the world will be used to study Sgr A* in radio waves, with 14 institutions taking part. The data from all these arrays will then be combined to produce a single set of data, known as very long baseline interferometry (VLBI).
The EHT will also be used to study the physics of accretion, how a black hole pulls in matter. And it will also observe a supermassive black hole in another galaxy 53.5 million light-years away, Messier 87, which is 4 billion times the mass of our Sun and thus has a larger event horizon than Sgr A* at 4 million solar masses.
So much data will be produced that it will have to be physically flown to two central locations, at the Max Planck Institute in Bonn, Germany, and the Haystack Observatory in Massachusetts, rather than transmitted. And owing to the large amount of data, it will take a while to process everything.
"The data will likely be processed throughout the summer [2017], then the EHT team will be analyzing the results through the fall," EHT Director Shep Doeleman told IFLScience, noting that "we don't know what we will find!"
"I am confident that we will have exciting data," he added. "All that said, we should be able to attempt imaging of both Sgr A* and M87 with the new data, but we will likely require even more observations. Results from these observations should be coming out early in 2018."
And what could we see? Well, as the name suggests, scientists will hope to see the circular event horizon around the black hole. This is the region beyond that nothing, not even light, can escape. The image should hopefully show gas around the event horizon, appearing brighter on one side as the black hole rotates.
It really is going to be pretty awesome. So stay tuned for what might be one of the most amazing scientific projects of the century.