February 16 2004 at 06:00AM
Argentine region may help unlock celestial secret
By Alistair Scrutton
Malargue, Argentina - In this desolate corner of Argentina, scientists are using a network of observatory stations spread over an area 10 times the size of Paris to uncover one of the universe's deepest secrets.
Researchers have littered 3 000 square kilometres with hundreds of UFO-like containers to scour the heavens for mysterious, rare and powerful cosmic rays that bombard Earth.
'We are on the very edge of science and the unknown'
Subatomic particles known as "cosmic bullets" are one of science's great unknowns. They pack more energy than any known particle in the universe, and determining what propels the "cosmic bullets" could challenge the laws of physics, such as the theory of relativity.
It could "make Albert Einstein turn in his grave", said Carlos Hojvat, an astrophysicist who manages the project funded by nations including the United States, Argentina and Brazil.
"We call these rays messengers from the cosmos. They could tell us about universe's origins. We are on the very edge of science and the unknown," he said.
The $50-million Pierre Auger Observatory in western Argentina was originally a project of the 1980 Nobel Prize-winner James Cronin of the University of Chicago.
Observatory construction began in Malargue, Argentina, in 2000. This year, the observatory started to measure particles blasted onto the atmosphere from outer space.
Scientists are unsure from where these tiny, but powerful, rays come. The rays are so rare that one hits an area the size of a football stadium every century.
The size of this observatory will give researchers unparallelled access to the "cosmic bullets" by allowing the measurement of about 50 rays every year.
Some scientists say the rays may be left over from the start of the universe, split seconds after the Big Bang. Others say they could be emitted from black holes.
Either way, discovering how the rays work will help explain how the universe operates, Hojvat said.
Low-energy particles constantly rain down on Earth, generating a background radiation long known to science. But it is the punch the "cosmic bullets" pack that baffles scientists.
"Physics offers us no explanation. These rays shouldn't exist,' said Xavier Bertou, a French astrophysicist who works on the Malargue project.
In 1991, US researchers discovered a subatomic particle travelling toward Earth with energy inside it six times more powerful than Einstein's theory of relativity allowed.
According to the observatory's Web site, it was as if "they went out to catch butterflies and caught an F-111" fighter plane that can travel at supersonic speeds.
"One possibility is Einstein's laws may not work," Bertou said.
So the observatory was built on the plains of Malargue to study the cosmic ray phenomenon. The area's flat land, clear skies and location - about 1 200 metres above sea level - made it an ideal spot to take accurate measurements of the "cosmic bullets."
By 2006, about 1 600 particle recorders - roundish containers filled with tonnes of pure water - will be spread over the plain. More than 200 recorders, set about one and a half kilometres apart, are up and running already.
Each of the 1 600 particle recorders act as a sensor. When a cosmic ray hits the Earth's atmosphere it "sprays" particles. The more powerful the ray, the bigger the "spray of particles," which are detected by the sensors.
When a ray hits the sensors, information about the size and direction of the ray is transmitted to a computer so scientists can later analyse it.
"We can guess within about 40 metres where the particle would have fallen. We'll go... and place a flag and of course drink some more champagne," Bertou said with a laugh.
Researchers say the immense power of these particles could be harnessed one day as a new energy source.
"It was the discovery of electrons that was crucial for electricity use," Hojvat said. "Practical impact often follows theory."