The conclusions of a new scientific survey call into question a long-standing theory that explains how cosmic rays are formed. The leading explanation for this might need some serious updating, or even replacing, investigators in charge of the study say.
Cosmic rays are highly energetic particle streams that contain protons, nuclei and other elements. Until not long ago, it was believed that they were produced when supernova remnants accelerated elementary particles to nearly the speed of light.
But results obtained from a dedicated space observatory appear to indicate that this is not the case. The telescope is called Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), and is operated by the Italian Space Agency,
Space reports.
Experts with ISA and its collaborating universities also believed that supernova remnants could behave like gigantic particle accelerators, spinning atoms and nuclei in a manner similar to how the Large Hadron Collider operates.
But PAMELA data show that this may in fact not be the case. Astrophysicists may need to return to the drawing board, and develop an entirely new theory to explain how cosmic rays are formed.
“Now we don’t know how cosmic rays are accelerated in space,” explains University of Rome astronomer Piergiorgio Picozza, who is also based at the National Institute of Nuclear Physics in Italy.
“Before our data, it seems that the paradigm is supernova remnants. Now we have to think of some refinement of this paradigm, or we need to find some other possibility,” he goes on to say.
The expert is also a coauthor of the new investigation, details of which appear in paper published in the March 4 issue of the top journal Science.
The Italian telescope, which can detect protons and helium nuclei, is capable of analyzing how many particles of different energies slam into it with the help of a spectrometer.
An amazing discovery came when PAMELA's operators found variations in the relationship between abundance and energy for protons and helium nuclei. The two values are different, which shouldn't happen if the two classes of particles were accelerated in the same supernova remnant.
“There is not any reason for nuclei to be accelerated in a different way. I think these results are really very important because they mean we need more-sophisticated processes to accelerate the cosmic rays,” Picozza explains.
“Our results, combined with the results of AGILE and Fermi, can change the way to think about the possibility of acceleration,” the expert concludes.
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