In reading the article that was the same sentence I copy-pasted to bring back here for discussion. Anyone have an idea what the reporter garbled into "faster than the speed of light?" I guess just "nearly the speed of light"?
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-detect...
It gets weird because you see evidence of these mesons or whatever way down below the part of the atmosphere where cosmic rays impact. Like, if you multiply the half life of the meson with the speed of light, you get a result that should be way shorter than the actual distance you see mesons (or what have you) actually traveling. Depending on how you look at it, it's like the mesons are traveling faster than the speed of light given how far they're going before decaying.
It turns out these particles are traveling so close to the speed of light that the passage of time is different for the particles than an observer on earth. Their half-life duration occurs within their frame of reference, which is different than ours. So even though the particle was traveling at (fake numbers) 1 kilometer a second and traveled 3 kilometers, it only had a lifespan of 1 second. It plays out this way because 3 seconds on earth transpired during the particle's 1 second in its own frame of reference and thus we saw it travel 3 kilometers during the particle's own 1 second, despite the speed of light being just 1 kilometer per second. So depending on how you look at the numbers it can seem like it was 3x faster than the 1km/s speed of light.
I realize this almost of creates more (and bigger) questions than answers.