NASA’s new visualization probes the flexible dance of binary black holes

A pair of black holes orbiting the Sun’s mass millions of times takes a hypnotic step in a new NASA view. The film follows how black holes distort and redirect the light emanating from the vortex of hot gas – called a storage disk – that surrounds each.

Viewed close to the orbital plane, each accumulation disk acquires a characteristic double appearance. But as one passes in front of the other, the gravity of the black hole in the foreground turns its partner into a rapidly changing sequence of arcs. These distortions manifest as light from both disks navigates through the tangled fabric of space and time near black holes.

“We see two supermassive black holes, one larger, with 200 million solar masses, and a smaller companion, which weighs in half,” said Jeremy Schnittman, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. created the view. “These are the types of black hole binary systems in which we believe both members could maintain accumulation disks for millions of years.”

The storage discs have different colors, red and blue, to facilitate the tracking of light sources, but the choice also reflects reality. The hotter gas emits light closer to the blue end of the spectrum, and the material orbiting smaller black holes has stronger gravitational effects that produce higher temperatures. For these masses, both storage disks would actually emit most of their UV light, with the blue disk reaching a slightly higher temperature.

Such visualizations help scientists imagine the fascinating consequences of the mirror of fun of extreme gravity. The new video doubles as a previous one produced by Schnittman, which features a solitary black hole from different angles.

Seen almost horizontally, the storage discs appear visibly brighter on one side. Gravitational distortion changes the light pathways that come from different parts of the discs, producing the distorted image. The rapid movement of the gas near the black hole alters the brightness of the disk by a phenomenon called boost Doppler – an effect of Einstein’s theory of relativity that illuminates the part that rotates towards the viewer and dims the part that rotates.

The visualization also shows a more subtle phenomenon called relativistic aberration. Black holes appear smaller as they approach the viewer and larger as they move away.

These effects disappear when you view the system from above, but new features appear. Both black holes produce small images of their partners orbiting each orbit. Looking closer, it is clear that these images are in fact marginal views. To produce them, the light in the black holes must be redirected by 90 degrees, which means that we observe the black holes from two different perspectives – with the face and the edge on – at the same time.

“A striking aspect of this new visualization is the self-similar nature of the images produced by gravitational lenses,” Schnittman explained. “The magnification of each black hole reveals multiple, increasingly distorted images of his partner.”

Schnittman created the visualization by calculating the path traveled by light rays from the storage disks as they made their way through the distorted space-time around the black holes. On a modern desktop computer, the calculations needed to make movie frames would have taken about a decade. So Schnittman teamed up with Goddard scientist Brian P. Powell to use the Discover supercomputer at NASA’s Center for Climate Simulation. Using only 2% of the 129,000 Discover processors, these calculations lasted about a day.

Astronomers expect that in the not-too-distant future they will be able to detect gravitational waves – space-time waves – produced when two supermassive black holes in a system similar to the one Schnittman described in a spiral and merge.