The project uses a technique called "distributed computing," which means it relies on computer time donated by private computer users to search through the data, an approach that is gaining popularity in many scientific fields. In fact, Einstein@Home was constructed with input from the architects of SETI@Home
, a popular distributed computing project that searches radio-telescope data for signals from extraterrestrial civilizations.Searching for gravity waves
Three cutting-edge observatories have been built to find gravity waves. All work by ricocheting laser beams between mirrors as scientists look for minute distortions in the beams' travel time. The Laser Interferometer Gravitational Wave Observatory (LIGO)
has one installation in Livingston, Louisiana, and a twin in Hanford, Washington. The German instrument, GEO 600
, is near Hanover, Germany, and was built in collaboration with the United Kingdom.
These observatories face a difficult task. A typical gravity wave is expected to distort a laser's path by less than a trillionth the width of a human hair. There's no lack of signals in the data from these instruments, but separating spurious noise from the distortions produced by passing gravity waves requires loads of computer processing.
"Our current instruments will be able to see the merger of two neutron stars to tens of millions of light-years," Allen told Astronomy
. But because the system is less sensitive to impulsive events — like exploding stars — he noted, "We will probably only be able to see supernovae within our own galaxy, although this depends upon the detailed physics of what happens during a supernova, which is not fully understood."
Scientists are conducting other searches for signals from these exotic sources, but Einstein@Home focuses on objects producing continuous waves, such as fast-spinning pulsars. This, says Allen, is the most computationally intensive task.
Einstein@Home looks for spinning neutron stars over the entire sky using the best 600 hours of data from LIGO observations made between October 2003 and January 2004. Scientists expect the next science run, to begin later this year, will be at least twice as sensitive.