Cosmic ray

"Cosmic radiation" redirects here. For some other types of cosmic radiation, see Cosmic background radiation and Cosmic background (disambiguation). For the film, see Cosmic Ray (film).

Cosmic flux versus particle energy at the top of Earth's atmosphere
Left image: cosmic ray muon passing through a cloud chamber undergoes scattering by a small angle in the middle metal plate and leaves the chamber. Right image: cosmic ray muon losing considerable energy after passing through the plate as indicated by the increased curvature of the track in a magnetic field.

Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy,[1] and from distant galaxies.[2] Upon impact with Earth's atmosphere, cosmic rays produce showers of secondary particles, some of which reach the surface, although the bulk are deflected off into space by the magnetosphere or the heliosphere.

Cosmic rays were discovered by Victor Hess in 1912 in balloon experiments, for which he was awarded the 1936 Nobel Prize in Physics.[3]

Direct measurement of cosmic rays, especially at lower energies, has been possible since the launch of the first satellites in the late 1950s. Particle detectors similar to those used in nuclear and high-energy physics are used on satellites and space probes for research into cosmic rays.[4] Data from the Fermi Space Telescope (2013)[5] have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernova explosions of stars.[6][better source needed] Based on observations of neutrinos and gamma rays from blazar TXS 0506+056 in 2018, active galactic nuclei also appear to produce cosmic rays.[7][8]

  1. ^ Sharma, Shatendra (2008). Atomic and Nuclear Physics. Pearson Education India. p. 478. ISBN 978-81-317-1924-4.
  2. ^ "Detecting cosmic rays from a galaxy far, far away". Science Daily. 21 September 2017. Retrieved 26 December 2017.
  3. ^ Cite error: The named reference HessNobelPresSp was invoked but never defined (see the help page).
  4. ^ Cilek, Vaclav, ed. (2009). "Cosmic Influences on the Earth". Earth System: History and Natural Variability. Vol. I. Eolss Publishers. p. 165. ISBN 978-1-84826-104-4.
  5. ^ Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; et al. (15 February 2013). "Detection of the characteristic pion decay-signature in supernova remnants". Science. 339 (6424): 807–811. arXiv:1302.3307. Bibcode:2013Sci...339..807A. doi:10.1126/science.1231160. PMID 23413352. S2CID 29815601.
  6. ^ Pinholster, Ginger (13 February 2013). "Evidence shows that cosmic rays come from exploding stars" (Press release). Washington, DC: American Association for the Advancement of Science.
  7. ^ Abramowski, A.; et al. (HESS Collaboration) (2016). "Acceleration of petaelectronvolt protons in the Galactic Centre". Nature. 531 (7595): 476–479. arXiv:1603.07730. Bibcode:2016Natur.531..476H. doi:10.1038/nature17147. PMID 26982725. S2CID 4461199.
  8. ^ Aartsen, Mark; et al. (IceCube Collaboration) (12 July 2018). "Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert". Science. 361 (6398): 147–151. arXiv:1807.08794. Bibcode:2018Sci...361..147I. doi:10.1126/science.aat2890. ISSN 0036-8075. PMID 30002248. S2CID 133261745.