PAMELA detector casts doubt on cosmic-ray origins
MAR 08, 2011
DOI: 10.1063/PT.5.025115
Universe Today : High-energy particles called cosmic rays are constantly bombarding Earth from all directions, and have been thought to come from the blast waves of supernova remnants, writes Nancy Atkinson for Universe Today. But new observations from the PAMELA cosmic-ray detector show an unexpected difference in the momenta (per unit charge) of protons and helium nuclei, the most abundant components of cosmic rays. The difference is extremely small, but if they both come from the same kinds of accelerators, their spectra should be very similar. Oscar Adriani and his colleagues, who used data from the PAMELA instrument, say their new findings are a challenge to our current understanding of the acceleration and propagation of cosmic rays, which may be controlled by unknown and more complex processes. Their results were published in Science.
© 2011 American Institute of Physics
