Giant Black Hole Swallows Smaller One in Breakthrough Simulation
Two black holes with a mass ratio of 100:1 are on the verge of colliding in this computer model.
Credit: Hans-Peter Bischof, Center for Computational Relativity and Gravitation at Rochester Institute of Technology

Call it a cosmic revision of David and Goliath: Scientists have simulated the showdown between a small black hole and a giant black hole. But unlike in the Biblical tale, the Goliath wins out.

Black holes are such mind-bending objects, the best that astronomers can do to see how these unexplored phenomena work is to simulate them with supercomputers. The new simulation, made possible through an advance in programming and months of computation, paired one black hole (the David) with one about 100 times as massive ? a situation that researchers suspect closely mirrors what happens often in our universe.

"Nature doesn?t collide black holes of equal masses," said Carlos Lousto, associate professor of mathematical sciences at Rochester Institute of Technology and a member of the school's Center for Computational Relativity and Gravitation, in a statement. "They have mass ratios of 1:3, 1:10, 1:100 or even 1:1 million. This puts us in a better situation for simulating realistic astrophysical scenarios and for predicting what observers should see and for telling them what to look for."

The simulation showed the giant black hole moving toward the runt and eventually consuming it. [Gallery: Black Holes of the Universe]

Until now, simulating the merger of two black holes with a mass ratio of 1:100 was thought to be impossible, requiring too much computing power, the researchers said. But Lousto and his RIT colleague Yosef Zlochower made advances in the ability of computers to model the physics theory of general relativity.

Even so, it took a supercomputer with 70,000 processors nearly three months to complete the complex simulation. That supercomputer, called the Ranger, is located at the Texas Advanced Computer Center at the University of Texas at Austin.

"Their work is pushing the limit of what we can do today," said Manuela Campanelli, director of the Center for Computational Relativity and Gravitation, who helped develop a computer technique that led to one of the first simulations of black holes on supercomputers in 2005. "Now we have the tools to deal with a new system."

The researchers plan to apply their new simulation processes to scenarios involving a pair of black holes with smaller mass ratios, and spinning binary black holes. They also hope the new model will aid in astronomers' attempts to observe black hole mergers using instruments such as the Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) and the space probe LISA (Laser Interferometer Space Antenna).

Lousto and Zlochower have submitted a paper to the journal Physical Review Letters describing their results.