As someone else has said, the article should say "faster than the speed of light in air". The Guardian article says: > Some charged particles in the air showe

As someone else has said, the article should say "faster than the speed of light in air". The Guardian article says: > Some charged particles in the air shower travel faster than the speed of light, producing a type of electromagnetic radiation that can be detected by specialised instruments. > One such instrument is the Telescope Array observatory in Utah, which found the Amaterasu particle. The Telescope Array actually has two different types of instrument for detecting the particles. Fluorescence Telescopes and Scintillation Detectors. According to the paper the "fluorescence detectors were not operating at the time (owing to bright moonlight)". Instead the particles were detected by the plastic scintillator surface detectors. I have found more information about the surface detectors here: http://www.telescopearray.org/index.php/about/surface-detection http://www.telescopearray.org/index.php/about/surface-detect...