Astronomers are capturing video of a black hole for the first time
CBC
Contrary to science fiction, black holes are not portals to other dimensions or cosmic vacuum cleaners that swallow up everything around them.
“The media always paints black holes as these pits of despair, and everything falls in, but they're much more fun than that,” astrophysicist Sera Markoff told Quirks and Quarks host Bob McDonald.
Markoff is part of a global team working to capture the first-ever video of a black hole, a scientific leap that could reveal how these mysterious cosmic objects behave.
“There's just an enormous amount of questions that we'd like to be able to answer about black holes,” she said.
In 2019, scientists released the first image of a black hole — a supermassive one at the heart of Messier 87 (M87) galaxy, about 50 million light-years from Earth — using the Event Horizon Telescope, a network of eight radio telescopes that operates as a single virtual instrument, linking facilities from Antarctica to Spain and Chile.
Markoff, the Plumian professor of astronomy at the University of Cambridge, says the EHT is now being used to track the colossal black hole in M87 in motion — an advance that could reveal details that still images cannot. There are now 12 telescopes in total, but only eleven will take part, as the telescope in the South Pole cannot see M87.
This time, images will be taken far more frequently — every three to four days from March through April — allowing astronomers to bring the black hole’s motion vividly to life.
The black hole in M87 is a prime candidate for viewing, as it evolves much more slowly compared to others, from several days to over a week, says Vincent Fish, operations data manager for EHT.
That slower pace allows astronomers to combine an entire night’s worth of data into a single image — snapshots that can then be stitched together over time to create what Fish calls “a time-lapse movie” of the black hole in motion.
Black holes themselves change little on human timescales, but the hot gas swirling around them does. That material forms a turbulent disk that constantly shifts and churns, says Markoff, who is also professor of theoretical astrophysics at the University of Amsterdam.
For the black hole in M87, those changes unfold over just a few days to a week. Capturing only a single snapshot each year, as researchers did previously, meant missing much of its dynamic behaviour.
While there is another suitable candidate for observation — Sagittarius A* — it may be too restless to film, according to Fish, who is also a research scientist at MIT Haystack Observatory.
Located at the centre of our home galaxy, Sagittarius A* changes so quickly that observations taken just an hour apart can appear to show entirely different objects, making detailed study difficult, he says.
According to Markoff, it will take a long time to process the many “petabytes of data” recorded at each of the telescopes before they can get to the point of analyzing them to construct the images they need for the video.
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