From Penn State: “Mystery solved: Super-energetic space particles crash to Earth from far away”

Penn State Bloc

Pennsylvania State University

September 21, 2017

An image of the Earth showing the continent of South America, with faint white streaks representing cosmic rays streaming toward the Pierre Auger Observatory in Argentina. Image: Pierre Auger Observatory

Super-energetic space particles, which were thought to have been blasted toward Earth from somewhere outside our solar system, now have been discovered to be from very far away indeed — from far outside our Milky Way galaxy. The discovery was made by an international team that includes Penn State scientists and the Pierre Auger Collaboration, using the largest cosmic-ray instrument ever built, the Pierre Auger Observatory in Argentina. A paper describing the discovery will be published in the journal Science on Sept. 22.

This animation illustrates the long journey of high-energy cosmic waves from the time they are shot into space from powerful events in galaxies far away from our Milky Way Galaxy until they eventually crash on Earth, leaving clues among the large array of cosmic-ray detectors in western Argentina, the Pierre Auger Observatory. Penn State scientists are members of the Pierre Auger Consortium.
Pierre Auger Collaboration

“After more than a century since cosmic rays were first detected, this is the first truly significant result from our analysis of the detections, which now have revealed the distant origin of these ultra-high-energy cosmic rays,” said Miguel Mostafá at Penn State. He and Stephane Coutu — both professors of physics and of astronomy and astrophysics and Fellows of the American Physical Society — lead teams of students and post-doctoral scientists in research at Penn State’s Pierre Auger Collaboration group.

Pierre Auger Observatory in the western Mendoza Province, Argentina, near the Andes

“Now we know that the highest-energy particles in the universe came from other galaxies in our cosmological neighborhood,” Mostafá said.

Mostafá and Coutu have been working on the project since 1996 and 1997, respectively, with support from the U.S. National Science Foundation. Mostafá has been a coordinator of the Auger team in charge of this analysis of cosmic-ray arrival directions, and is one of the corresponding authors on the Science article.

Although the Pierre Auger Collaboration’s discovery clearly shows an origin outside our Milky Way galaxy, the specific sources that are producing the particles have not yet been discovered. “We are now considerably closer to solving the mystery of where and how these extraordinary particles are produced, a question of great interest to astrophysicists,” said Karl-Heinz Kampert, professor of physics at the University of Wuppertal in Germany and spokesperson for the Pierre Auger Collaboration.

See the full article here .

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