A Transatlantic Black Hole Merger

Scientists in the United States and Germany will merge two supercomputers across nine time zones next week to watch a neutron star crash into a black hole. The project will push the limits of intercontinental networking, a way to get more bang for the supercomputer buck. The simulation also may yield new insights into the violent collisions of dense objects that are predicted to send gravitational waves rippling across the universe.

Researchers will link two SGI-Cray T3E supercomputers, one at the San Diego Supercomputer Center, the other at the Konrad Zuse Institute in Berlin. The machines rank as 36th and 49th fastest in the world, respectively. But together, the computers would climb to 23rd fastest, capable of nearly 200 billion calculations per second. High-speed data lines have merged supercomputers in this way before, but never spanning an ocean basin. "It's quite a challenge to create a single integrated system," says computer scientist Ian Foster of Argonne National Laboratory in Argonne, Illinois. Programming protocols and communications hardware are vastly different between the continents, Foster says, requiring an extensive set of software to create a smooth interface.

If all goes well, attendees at the Supercomputing '98 conference will see the collision displayed live in 3D in Orlando, Florida, next Tuesday and Thursday. Project coordinators hope to maintain speeds of 30 million bits per second (Mbs) throughout the vast data network, says computer scientist John Shalf of the University of Illinois, Urbana-Champaign. That's some 1000 times faster than the sluggish pace most home users of the Internet endure. Shalf hopes to bump that rate to 155 Mbs next year, which would not affect the speed of computation but would allow for faster updates of the 3D displays.

The potential payoffs in relativity theory are exciting, says project leader Ed Seidel of the Max Planck Institute for Gravitational Physics in Potsdam, Germany. "The largest supercomputers are finally approaching the speed and memory required to solve the complete set of Einstein's equations for the first time," Seidel says. Those equations predict that colliding black holes, neutron stars, and other exotic objects should throw off energy in the form of gravitational waves. The simulation, set to last one hour, may help theorists predict the shapes and durations of waves, which would shrink or stretch space as they pass. Sensitive detectors being built on Earth may see these disturbances in the space-time fabric within the next decade.