A New Mystery – Powerful Cosmic Rays
An artist’s illustration of a cosmic ray entering the atmosphere above H.E.S.S. (Image credit: MPIK/H.E.S.S. Collaboration)
As Cosmic Rays travel through space they lose energy interacting with magnetic fields and light. Thus, it is theoretically rare that very high-energy cosmic rays reach Earth.
A new observatory in Namibia -High Energy Stereoscopic System (HESS) is specialised for detecting cosmic rays by observing and analysing the Cherenkov radiation from showers of particles produced as the cosmic rays hit the atmosphere. Surprisingly they have detected electrons and positrons with such high energy (<40 TeV) that they must have originated nearby – calculated as within a few thousand light-years i.e. within the local part of our galaxy.
At present it is unknown what and where the source of these rays could be – they can be produced by highly energetic objects like supernovas and pulsars and presumably other unknown objects, but…
