APS News

Use Your Computer to Help Find Gravitational Waves

Einstein@HomeChances are your computer spends much of its lifetime doing practically nothing. While you're at lunch, in meetings, or stuck in traffic, the PC on your desk sits idly marking time at billions of clock cycles per second. At best, it might run a diagnostic test now and then, or generate oddly-hypnotic, but essentially useless, screensaver graphics. Perhaps you've wondered if there's something better that the beige box can do with its time. If so, you're in luck; your computer will soon be able to while away the hours crunching numbers for astrophysics research thanks to Einstein@Home.

The project is part of the World Year of Physics 2005 (WYP2005), which celebrates the importance and vitality of physics in the new millennium and marks the 100th anniversary of Einstein's miraculous year.

The Laser Interferometer Gravitational Wave Observatory (LIGO) Scientific Collaboration (LSC) and the APS are working to develop Einstein@Home to allow anyone with a broadband Internet connection to contribute their computer's spare clock cycles to cutting-edge, gravitational wave research.

It is a distributed computing project that relies on donated computational power to search for signs of gravitational waves in data from LIGO's four kilometer, interferometric gravitational wave detectors in Hanford, WA and Livingston, LA, as well as in data from GEO, a 600 meter interferometer in Hanover, Germany.

Most signals that will be the focus of gravitational wave observations at LIGO and GEO involve brief, catastrophic events, such as black hole mergers and supernova explosions. Einstein@Home, on the other hand, is specifically intended to search for less transient, sinusoidal signals coming from rapidly rotating, aspherical, massive bodies such as some neutron stars. Because the locations of only a few likely sources are currently known, Einstein@home will conduct of a whole-sky search for wave sources.

These types of searches require enormous amounts of computational time, at levels that currently can only be achieved with massive supercomputing systems or through distributed computing projects that involve tens to hundreds of thousands of participants.

Distributed computing is rapidly gaining popularity as a method to address problems ranging from protein folding, to searches for radio emissions from extraterrestrial civilizations, to high precision calculations of pi.

Einstein@Home is among the first, publicly available, distributed computing efforts dedicated to a significant physics experiment. Although strong, indirect evidence of gravitational waves already exists in studies of the spin-down of a binary pulsar, it is possible that Einstein@Home will lead to the first direct observation of the gravitational waves predicted by Einstein's general theory of relativity.

Einstein@Home will primarily be designed to run data analysis algorithms when participants' computers are idle, and will include a screen saver that displays computational progress. Calculations can also be run continuously as a background process to make more complete use of excess computational power.

Bruce Allen of the University of Wisconsin-Millwaukee's LSC group is responsible for leading the development of Einstein@Home. He and his colleagues are hopeful that as many as a million people will dedicate spare CPU cycles to the gravitational wave search, but even with only tens of thousands of participants, Allen is confident that Einstein@Home will lead to important and interesting results.

The Einstein@Home client application will be available for download in early 2005. In the meantime, further information and an online pre-registration form are available at the WYP website.

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Editor: Alan Chodos
Associate Editor: Jennifer Ouellette