Fans of the British sci-fi comedy Red Dwarf are well aware of one of the chief problems when it comes to black holes. As the Dwarf‘s AI, Holly, put it after an unfortunate encounter with one of the cosmic maelstroms, “The thing about a black hole — its main distinguishing feature — is it’s black. And the thing about space, the color of space, your basic space color, is black. So how are you supposed to see them?” The logic is airtight, but it’s not stopping a group of scientists who are convening in Tuscon, Arizona this Wednesday to plan an attempt to spit in logic’s eye and actually take a picture of a black hole.
Jokes aside, Red Dwarf raises a valid question: how exactly can you capture an image of an object that swallows up light? Answering that question is the purpose of this week’s conference, being organized by Dimitrios Psaltis, associate professor of astrophysics at the University of Arizona’s Steward Observatory, and Daniel Marrone, an assistant professor of astronomy at Steward Observatory. The project has been dubbed the Event Horizon Telescope (no relation to the crappy Paul Anderson movie), and it looks to take advantage of emergent technology to do what seems, on the face of it, impossible. To start with, the project will use radio waves, rather than visible light, because they are better able to penetrate all the star stuff that lays along the galactic plane between us and the theoretical black hole. Second, the trick is not to photograph the black hole itself, but instead the swirl of matter spiraling around and into it, thus giving you a look at the shape of the phenomenon itself.
Sheperd Doeleman, assistant director of the Haystack Observatory at Massachusetts Institute of Technology, explains further:
As dust and gas swirls around the black hole before it is drawn inside, a kind of cosmic traffic jam ensues. Swirling around the black hole like water circling the drain in a bathtub, the matter compresses and the resulting friction turns it into plasma heated to a billion degrees or more, causing it to ‘glow’ — and radiate energy that we can detect here on Earth.
The project also looks to answer one of astronomy’s more intriguing questions: is there a giant black hole at the center of our galaxy? The immense project will link up to 50 radio telescopes across the globe, effectively making a “virtual telescope with a mirror that is as big as the Earth,” says Doeleman. If the project can image the “shadow” of a black hole in the center of our galaxy, it will prove conclusively that it exists.
By examining the black hole’s “shadow,” scientists will be able to test how Einstein’s theory of General Relativity holds up when exposed to the strongest gravitational field in the universe.