At the heart of every galaxy is a black hole, where gravity is so strong that nothing can escape its boundary. Sometimes when two galaxies merge, their black holes are trapped in a locking phase, permanently circling each other in interstellar tango.
A new animation from NASA reveals what it would look like if you filmed a pair of supermassive orbital black holes, called a binary system, in action.
In the visualization, the black holes are marked by different colors. The orange one is 200 million times more massive than the sun. His blue companion weighs about half that much. Both are surrounded by glowing circles of hot gas and space debris, known as the accumulating disk.
When one black hole moves in front of the other, its strong gravity distorts the light from its partner’s accumulating disk.
As a result, the black hole in the background looks like it’s warming up into pieces that freeze around the other – a bit like a toilet mirror.
Once the black holes pass each other, those distorted pieces seem to flow back together.
Black holes look different depending on your viewing point
The black holes appear smaller as they move closer to the viewer and larger as they move further into the background, according to Jeremy Schnittman, a NASA astrophysicist who created the new animation.
Using a cluster of supercomputers, Schnittman was able to calculate, frame by frame, how light from the two disks would accumulate as the two black holes dance around each other. Normally, those calculations would have taken a decade on modern
, but Schnittman completed them in about a day.
Its visualization shows that black hole components change in appearance depending on how you look at them.
When viewed above or below, the accumulator disc of each black hole looks like a near perfect circle, with a small image of its partner reflected near the center.
“Zooming into each black hole reveals several distorted images of his partner,” Schnittman said in a statement.
When viewed side by side, however, the accumulator disk looks like a rainbow of fire sliding around the center of the black hole. That rainbow warms up when the black holes pass each other.
From this viewing point, the accumulator disk appears brighter on one side than the other. As a black hole spins, the rotating cloud of gas and debris also spins. So the disc material moving towards our eyes would seem brighter than the material moving away – a bit like a lighthouse torch.
According to Schnittman, a pair of black holes like those depicted in the new animation will eventually merge into one gargantuan black hole – but not before dancing around for a long time.
“These are the types of black hole binary systems where we believe both members could maintain accumulator disks that last millions of years,” he said.
Aria Bendix contributed in telling this story.