Space project may unravel mysteries of the universe (Re-issue)November 18th, 2007 - 11:32 am ICT by admin
Washington, Nov 18 (ANI): Astrophysicists have started work on an international project to look into space for gravitational waves, which may hold secrets to the nature of black holes, the unknown properties of nuclear material and maybe even how the universe began.
Gravitational waves are travelling ripples in space-time, which are produced when massive objects in space move violently. The waves carry the imprint of the events that cause them. Scientists already have indirect evidence that gravitational waves exist, but have not directly detected them.
But now with the LIGO (Laser Interferometer Gravitational-wave Observatory), consisting of detectors at two US sites, physicists from UWM (University of Wisconsin Milwaukee) have started searching for these waves.
The LIGO observatories use lasers to accurately monitor the distance between a central station and mirrors suspended three miles away along perpendicular arms. When a gravitational wave passes by, the mirror in one arm will move closer to the central station, while the other mirror will move away.
“The change in distance caused by stretching and squeezing is what LIGO is designed to measure,” said Alan Wiseman, associate professor from UWM.
LIGO records a series of numbers and feeds them to several supercomputer clusters around the country, including UWM’s Nemo cluster.
The computer’s job is to sort out the numerical patterns representing gravitational waves buried in ambient noise produced by lots of other vibrations.
These vibrations range from internal vibrations of the equipment itself, to magnetic fluctuations from lightning storms, to seismic vibrations from trains rolling along the tracks a few miles from the observatory, or from earthquakes on the other side of the world.
“There are thousands or even millions of different signals that could be emitted from space,” said Wiseman. “So you have to take each segment of data individually. That turns out to be a formidable computational problem,” he added.
“The strings of numbers from LIGO are like tracks on a compact disk,” said Patrick Brady, associate professor from UWM. “That means, once detected, gravitational-wave signals can be converted into sound,” he added.
In fact, scientists have already simulated, based on mathematical predictions, what certain events in space will sound like. Those analyzing the data from space could actually listen to the data.
The best hope is to detect events relatively close to Earth.
“The events we are looking for may only happen once every million years in our galaxy,” said Wiseman. “But if our instrument is sensitive enough to see such events in, say, one million galaxies, then the probability of detecting something is much larger,” he added.
“We’ve only been able to find out about the universe since it became cool,” said Xavier Siemens, a UWM physicist. “But with gravitational waves, we’ll see the universe when it was much younger and hotter,” he added. (ANI)
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