Sagittarius A*

To create the first image of the Milky Way’s black hole, scientists ran numerous simulations of the swirling envelope of plasma that encircles it. This clip shows the version of the animated computer model that seemed to best mirror the radio wave data collected by the Event Horizon Telescope. Credit: Abhishek Joshi/UIUC

In the center of the Milky Way lurks a fairly quiescent monster, a relatively small supermassive black hole named Sagittarius A*, a tiny entity compared to its much larger cousin, M87. How these engines of creation and destruction work vis a vis the galaxies that house them has perplexed researchers for years but with sophisticated tools such as the Event Horizon Telescope, these objects of fascination and dread are becoming better understood as seen by Knowledgable Magazine's in-depth article titled What the image of the Milky Way’s black hole really shows.

Black holes keep their secrets close. They imprison forever anything that enters. Light itself can’t escape a black hole’s hungry pull.

It would seem, then, that a black hole should be invisible — and taking its picture impossible. So great fanfare accompanied the release in 2019 of the first image of a black hole. Then, in spring 2022, astronomers unveiled another black hole photo — this time of the one at the center of our own Milky Way.

The image shows an orange, donut-shaped blob that looks remarkably similar to the earlier picture of the black hole in the center of galaxy Messier 87. But the Milky Way’s black hole, Sagittarius A*, is actually much smaller than the first and was more difficult to see, since it required peering through the hazy disk of our galaxy. So even though the observations of our own black hole were conducted at the same time as M87’s, it took three additional years to create the picture. Doing so required an international collaboration of hundreds of astronomers, engineers and computer scientists, and the development of sophisticated computer algorithms to piece together the image from the raw data.

The new image of the black hole Sagittarius A*, confirms and refines previous predictions of its size and orientation. The mass of the black hole determines its size, or what scientists call its gravitational diameter. The point at which no light can escape from the black hole, called the event horizon, is determined by this mass and by the spin of the black hole. Hot plasma speeds around the massive object in the accretion disk, emitting radio waves. Those radio waves are bent and warped by gravity (through the effect of “gravitational lensing”) to produce the image of the orange outer circles. The black hole shadow and emission ring shown here are gravitationally-lensed projections of the far-side of the black hole’s event horizon and accretion disk, respectively. Source reporting by K. McCormick/Knowable Magazine

Read the rest of this detailed piece to see how our black hole was imaged if you dare. :)