A new mystery on the origin of cosmic rays

IceCube Neutrino Observatory architecture diagram
IceCube Neutrino Observatory architecture diagram

Cosmic rays are energetic charged particles, typically protons, coming from space. The effects of cosmic rays were already detected at the end of the nineteenth century by various researchers including Antoine Henri Becquerel, Marie Curie and Pierre Curie. At the beginning of the twentieth century Domenico Pacini and Victor Franz Hess independently carried out research on the origin of cosmic rays and with various experiments they showed their extraterrestrial origin. In 1936, Hess won the Nobel Prize for physics for his research on cosmic radiation.

The research to reach an understanding of the origin of cosmic rays continue to this day. There are probably several sources of cosmic rays and the according to one of the theories they’re created as a result of gamma-ray bursts.

Fluxes of neutrinos should be produced along with cosmic rays by the interaction of protons and photons, therefore astrophysicists Nathan Whitehorn and Pete Redl tried to detect tehm with the IceCube Neutrino Observatory with (or simply IceCube) (photo ©NASA-verve).

IceCube is a neutrino detector built in recent years in Antarctica by dipping in the ice at various depths a series of detectors containing spherical geometry of photomultiplier tubes (PMT). These optical sensors are a total of 5,160 and are intended to detect the rare neutrino interactions with the common matter. Initially, they built the Antarctic Muon And Neutrino Detector Array (AMANDA), a smaller detector that was later integrated in the bigger IceCube.

The detection of neutrinos that should be associated with cosmic rays coming from from three hundred gamma ray bursts observed gave negative results. A few years go, the IceCube was not yet completed but now it’s working at full capacity therefore it will keep on collecting data.

However, the results already obtained make the scientist think that it’s necessary to review the current theories on the origin of cosmic rays. Using the IceCube and other highly advanced instruments built in recent years a lot of new important data can be acquired to solve this mystery.

For example, the Large Area Telescope (LAT) of the Fermi Gamma-ray Space Telescope has been studying gamma rays sources for nearly four years identifying many of them. The research also covers cosmic rays and about two years ago researchers announced that the shock waves in supernova remnants act as accelerators for cosmic rays.

In short, any research in which new instruments can be used extend our knowledge with often surprising discoveries that force scientists to revise their theories. On the other hand, this is exactly how the scientific method works.

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