Home PCs to find Einstein's gravity waves
The downtime of a million computers is to be harnessed in the biggest search for never-seen-before gravity waves as they ripple through the cosmos.
US scientists at the Laser Interferometer Gravitational Wave Observatory (LIGO), working with colleagues from the around the world including Australia, are inviting home computer users to take part in the Einstein@Home project.
Like previous distributed-computing projects such as SETI@home this one relies on private computer users donating computer time to analyse huge amounts of scientific data.
But instead of searching for signals from extraterrestrials, modelling climate change or protein folding as others have done, the goal of this latest project is finding gravity wave-emitting compact stars.
Distorting space and time
According to Einstein's general theory of relativity, gravity distorts space and time. To test his theory Einstein predicted that waves of gravity would result from major distortions in space such as exploding stars, spinning neutrons, colliding black holes, even the Big Bang.
Scientists have spotted such waves indirectly, from observations of how paired neutron stars influence each other's orbits. But nobody has seen them directly.
Measuring them for the first time would tell scientists about the universe immediately after it formed.
The international team of scientists has been analysing LIGO data for the past two years.
They are trying to measure the exact frequency and shape of gravity waves and what this reveals about the objects that emit them. Were they neutron stars, black holes, waves from the early universe or unknown cosmic entities?
LIGO's observatories use perpendicular pairs of laser beams to measure the gravitational waves detected.
When a gravitational wave passes by, it can change the lengths of the paths the laser beams follow by tiny amounts. Scientists observe gravitational waves by comparing these changes in the laser beam paths.
Sharing computing power
The problem is that LIGO generates an enormous amount of data. A computer big and powerful enough to search through it simply isn't available. That's why scientists have turned to home computer users for help.
Anyone can download a special screen saver to automatically analyse a small chunk of LIGO data on his or her computer, using its idle time to search particular frequencies for a gravity wave source.
Given the huge amount of data and the smallness of the signals being sought, the more computers enlisted the better, the scientists say.
Professor David McClelland, at the Australian National University's Centre for Gravitational Physics, says detecting gravitational waves would open a new window to the universe.
"Until now it's only been possible to observe the universe using light. Detecting gravity waves would be like hearing for the first time. It would tell us much more about the universe and reveal new objects that we didn't know were there because they don't emit electromagnetic [light] waves."