UP’s Prof Roger Deane with a simulated image of a black hole.
First-ever image of a black hole released
At 15:07 on 10 April, images of a black hole were released by scientists from the Event Horizon Telescope (EHT). This is the first time in history that scientists have managed to capture the image of a black hole. Seven conferences were simultaneously held worldwide, including one press conference at the University of Pretoria, to reveal the work of the EHT project. Since an observation in April 2017, the EHT has been working to produce a image of the supermassive black hole, M87, in the nearby Virgo A galaxy. M87 is 6,5 billion times the mass of our sun and is over 53 million light years away.
During the event, a member of the EHT board said that this discovery is “a game changer” because it allows for experimentation in ways that were “previously inaccessible.” This will transform research around gravity, and further confirms Einstein’s Theory of Relativity. The EHT project is an international collaboration consisting of a network of eight radio telescopes across the world. This was a “truly global collaboration” according to Roger Deane, Associate Professor of Physics at University of Pretoria, who formed part of the international team of 200 scientists that spent 2 years producing the image from the data collected in April 2017. One UP PhD student’s paper was cited in two of the six publications produced today, and UP’s Computational Intelligence Research Group has also been involved in developing techniques critical to other South African astronomical projects, such as the Meerkat and Square Kilometre Array radio telescopes, as well as the EHT.
Imaging M87 is the equivalent to observing a mustard seed in Brussels from 6000 kilometres away in Washington D.C. The telescopes involved were positioned in Spain, Chile, Mexico, Arizona (USA), Hawaii and the South Pole. This network telescopes uses what is called Very Long Baseline Interferometry (VLBI), which creates something similar to a virtual telescope that is almost the size of Earth.
The ‘event horizon’ is the point beyond which nothing can escape the black hole, according to Einstein’s theory of special relativity. An object’s escape velocity refers to the speed at which one would need to exceed to escape the gravitational pull of the black hole. This speed is faster than the speed of light at the event horizon, which nothing can travel faster than in space.
The EHT team warned to “stay cued, we will be back” with more reveals from the project to come, particularly on Sagittarius A*, the closest black hole to earth. Abbreviated to SgrA*, it lies almost 30 000 light years away near the centre of the Milky Way and is 4 million times the mass of our Sun. Despite its size, the distance from the earth means that producing an image of its event horizon is equivalent to mapping the individual dimples of a golf ball in Los Angeles while standing 4 500 kilometres away in New York, according to Space.com. UP’s Vice-Chancellor, Professor Kupe, said that although discoveries made out of curiosity may seem “esoteric” on the surface, “years down the line it transforms lives and communities.” He added that African participation in this discovery changes the narrative about African capabilities. As one scientist from the EHT board said, “the history of science will be divided into the time before the image, and the time after the image […] if there is a moment for all of us, it is today.”
Image: up.ac.za – UP’s Prof Roger Deane with a simulated image of a black hole. Background image: T. Bronzwaer, J. Davelaar, M. Moscibrodzka, H. Falcke/BlackHoleCam