VIDEO: Simulation of a merger of two black holes, produced by a Georgia Tech team including Matt Kinsey, Karan Jani, and Michael Clark. Click to play. (No audio.)
When astrophysicists saw the squiggly lines recorded by LIGO detectors in Washington and Louisiana in September 2015, they immediately suspected that the gravitational waves they were seeing — the first ever observed — signaled the collision of two massive black holes.
For ordinary folks, however, the squiggles — which confirmed another prediction of Albert Einstein’s 1915 general theory of relativity — just didn’t say very much.
But for Karan Jani, a member of the LIGO team and a doctoral candidate in Georgia Tech’s School of Physics, and Matt Kinsey, another doctoral candidate, the waves offered an opportunity to apply simulation and visualization technology to help a broader audience share in the excitement the scientists were experiencing.
Using Einstein’s equations, Jani created a simulation of the collision of black holes recorded by the Laser Interferometer Gravitational-wave Observatory (LIGO) detectors. The event itself lasted just a half second, but simulating it required an estimated 50,000 hours of high-performance computer time — using a Georgia Tech computer cluster and a supercomputer at the Texas Advanced Computing Center.
Kinsey then used a program known as VisIt to convert the simulations to a 3-D animation; frames from the animation were used to create a poster that was shown by media around the world.
“These graphics are really the only way that people in general could have grasped what the discovery is all about,” Jani said. “To take Einstein’s equations and solve them, you need a very sophisticated numerical infrastructure, and we were fortunate to have had access to this.”
When the black holes collided 1.3 billion years ago, the gravitational waves radiated away from them in a three-dimensional pattern. But since the waves were detected at only two locations on Earth, the full 3-D nature of the event could not have been appreciated without the simulation and visualization.
The two black holes were each roughly 30 times the mass of our sun, but because black holes are the densest objects in the universe, the resulting body would have had an area perhaps no larger than Montana. The amount of energy released by the collision was 50 times the total energy emitted by the universe at that instant.
“It is truly remarkable that we were here at the right time and with the technology to detect this,” Jani said. — John Toon
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