How do you take a picture of a black hole, a celestial object so dense it gobbles up light with its monstrous gravitational pull? An ambitious group of determined scientists will convene this week to discuss a project called the Event Horizon Telescope, with the goal of photographing a supermassive black hole deep in the heart of our Milky Way galaxy — the first such snapshot ever. "Even five years ago, such a proposal would not have seemed credible," says MIT's Sheperd Doeleman, the project's lead researcher, in a press release. "Now we have the technological means to take a stab at it." Here's the plan:
First off: What exactly is a black hole?
It's a "place in space where gravity pulls so much that even light cannot get out," says NASA. Black holes are often created by the death of a star, when an immense amount of matter is squeezed into an impossibly smaller space, drastically strengthening gravity's pull. Some black holes are as tiny as a single atom — others have a mass equivalent to millions of stars.
Why is it so hard to photograph a black hole?
Since no light can get out, black holes are invisible. Scientists can only hope to catch a glimpse of a black hole's "shadow," says Space.com. "As dust and gas swirls around the black hole before it is drawn inside, a kind of cosmic traffic jam ensues," notes Doeleman — like water draining in a bathtub. That "shadow" is known as a black hole's "event horizon" — and it can be photographed.
Are there other obstacles?
There sure are. Though the black hole that Doeleman and Co. want to photograph is estimated to be four million times bigger than our sun, it is "extremely compressed and far away," says Irene Klotz at Discovery News — about 26,000 light years from Earth. "To astronomers, it's like looking at a grapefruit on the moon."
So... how do you take a photo of it?
Scientists would need an "enormous" telescope with a mirror as large as a planet, says Travis Korte at The Huffington Post. Obviously, constructing a single telescope that big and powerful isn't possible. So the Event Horizon Telescope would combine the networked viewing power of some 50 telescopes from all over the globe, from Hawaii to the South Pole. "In essence," says Doeleman, "we are making a virtual telescope with a mirror that is as big as the Earth."