Earlier this year, astronomers revealed one of humanity’s greatest achievements in science: the very first image of a black hole. (Of course, the photo was not directly of the black hole itself, that would be impossible.)
Capturing the image took hundreds of scientists, years of work and eight telescopes, but the low resolution makes it hard to get an idea of how black holes actually look. Now, a new NASA animation offers a clue.
The visualization, created by Jeremy Schnittman at NASA’s Goddard Space Flight Center, shows how the gravity of a black hole deforms the light around it, like a carnival mirror. The gravitational attraction is so strong that we can see, from our point of view, the light that goes under and behind the black hole.
“Seen nearly edgewise, the turbulent disk of gas churning around a black hole takes on a crazy double-humped appearance. The black hole’s extreme gravity alters the paths of light coming from different parts of the disk, producing the warped image. The black hole’s extreme gravitational field redirects and distorts light coming from different parts of the disk, but exactly what we see depends on our viewing angle. The greatest distortion occurs when viewing the system nearly edgewise.”
Supermassive black holes are located in the center of most major galaxies, and the way they arrived is a mystery. What came first, the black hole or the galaxy, is one of the big questions of cosmology.
What we do know is that they are really enormous, like millions or billions of times the mass of the Sun; that they can control the formation of stars; that when they wake up and start feeding, they can become the brightest objects in the universe.
In fact, the very first simulated black hole image, computed using a 1960s IBM 7040 punch-card computer and hand-drawn by the French astrophysicist Jean-Pierre Luminet in 1978, still looks like a lot to the simulation of NASA.
In both simulations, you see a black circle in the center. That is the event horizon, the point where the electromagnetic radiation (light, radio waves, X-rays, etc.) are no longer fast enough to reach the escape velocity due to the gravitational attraction of the black hole.
You might notice that the left side of the black hole’s accretion disk — a ring of hot matter that orbits a black hole near the speed of light — appears brighter than the right side, a phenomenon that’s explained by the Doppler effect.
“Glowing gas on the left side of the disk moves toward us so fast that the effects of Einstein’s relativity give it a boost in brightness; the opposite happens on the right side, where gas moving away us becomes slightly dimmer,” NASA wrote. “This asymmetry disappears when we see the disk exactly face on because, from that perspective, none of the material is moving along our line of sight.”
The visualization hopefully makes it easier to understand Einstein’s theory of special relativity.
“Simulations and movies like these really help us visualize what Einstein meant when he said that gravity warps the fabric of space and time,” said Schnittman. “Until very recently, these visualizations were limited to our imagination and computer programs. I never thought that it would be possible to see a real black hole.”