A team of astronomers from the Pierre Auger Observatory in Malargue, Argentina, has made an astonishing discovery - that the rare ultra-high energy cosmic rays which come to Earth from space arrive from specific areas far outside the Milky Way galaxy.

Axar.az reports that, in a new study published in Science, Pierre Auger Collaboration, an international astronomy team searching for answers about the cosmic origins of extremely high-energy cosmic rays (i.e. subatomic particles traveling at speeds close to the speed of light), have come up with an answer.

After observing the arrival patterns of over 30,000 particles with the highest energy using the Pierre Auger Observatory's array of 1,600 cosmic ray detectors, researchers were able to create a map of their distribution along the sky. Their map finds that most of these particles seem to come from particular areas of galaxies far outside our own.

The source of these particles, which have energies a million times greater than that of the particles accelerated by the Large Hadron Collider in Switzerland, remains unknown, but the Pierre Auger Collaboration's findings give astronomers insight into where to search.
"
We are now considerably closer to solving the mystery of where and how these extraordinary particles are created, a question of great interest to astrophysicists," said professor Karl-Heinz Kampert, spokesman for Auger Collaboration, a project which involves more than 400 scientists from 18 countries.

According to astrophysicist Bruce Dawson, the findings are significant, because "this is the first conclusive evidence that real atomic material, not just starlight, arrives at Earth from distant galaxies."

Paolo Privitera, professor of astronomy and astrophysics at the University of Chicago, said that the study "unequivocally establishes that ultra-high-energy cosmic rays are not just random wanderers of our nearby universe. The imprint detected in their arrival directions – a tantalizing evidence for extragalactic origin –required several years of observations with a detector working…'like a Swiss clock,'" he said.

Scientists still aren't sure what's causing the particles to be charged up with such immense power, but the study serves as an important first step in finding out. Some researchers postulate that the high-energy particles may have come from galaxies densely packed with stars, or those that have massive, explosive black holes in their centers.

Figuring out the origin and mechanisms behind these ultra-high-energy cosmic rays may help to explain how galaxies form, and what it is about them that leads to these particles' creation.