One of the bright spots in the dark years of the 2020s was, paradoxically, the pictures of black holes—the first direct visual evidence for the astronomical phenomenon.
Taken by astronomers with the Event Horizon Telescope, the image splashed across the front pages of newspapers around the world. The 2019 picture captured a black hole in a galaxy millions of light-years away from us; but in 2022, they have announced the first image of the supermassive black hole that squats at the center of our own galaxy.
Named Sagittarius A*, this black hole is no threat to us Earthlings. But it could help us understand how the Milky Way formed, as well as the strange physics that happen in and near black holes.
“The galactic center black hole is special for us,” said John Carlstrom, the Subrahmanyan Chandrasekhar Distinguished Service Professor of Astronomy, Astrophysics and Physics at the University of Chicago. “In a sense, it's our own black hole. We'd really like to know and understand what's going on there, and to be able to tie it to the dynamics of our galaxy as a whole.”
A telescope the size of the Earth
Black holes are so named because they themselves cannot be seen—they are regions of space where gravity is so powerful that not even light can escape. The bright “donuts” of light in the famous images are actually light and matter being ripped apart and chewed up by the black holes.
But these black holes are so far away that even such hazy images marked an incredible feat of science, engineering and global collaboration.
Scientists figured out that if they pointed telescopes all around the Earth at the same spot at the same time, and cross-referenced the data, it could act as though it was one big telescope covering the size of the Earth. This is what the “Event Horizon Telescope” really is—a collection of telescopes around the world that are normally used for other purposes.