When I try to bend my mind around this I come up with:
The particle started its journey a long time ago and quite a way away. In a fixed environment it travels a fixed distance in a fixed amount of time at a fixed (and limited) speed. So far, so normal.
But while the particle moves, the very space (space-time?) it moves inside expands as more space is created. And because we’re talking a long time, the universe now is a lot larger than it was when the particle started to move. So if you look at the distance travelled and the time this took and still assume a constant ratio between distance, time and speed it looks like the speed is faster than it should be. But what actually changed is not the speed of the particle, but space itself.
The speed of light in a vaccuum is a hard upper speed limit, but the SoL through a given medium is not. It’s pretty common for high-energy particles to exceed e.g. the speed of light in air or water (given by the phase velocity which FGD135 mentioned in their quote) which gives us Cherenkov radiation:
As far as I understand it, redshift/blueshift is about photons (and protons, electrons, and whatnot - matter waves?) and the relative motions/positions of radiation sources and their observers.
But this thing?
Looks like The Guardian’s article was mainly cribbed from this release by the University of Utah
which mentions nothing about the particle travelling faster than light, seemingly or not.
It just says that the particle was extremely energetic and that nobody can satisfactorily explain what it was or where it came from.
Since The Guardian has a well established track record of never ever getting anything wrong at all, the faster-than-light bit reimains a mysterious mystery.
oh dear, I really messed your head up this time, havent I? the deleted part in the guardian wasnt talking about the particle either, but secondary particles, triggered by that event in the upper atmosphere (airshower), which then exceeded atmospheric c (I guess).
This article was amended on 24 November 2023 to clarify some of the wording, based on agency copy, that was used in an earlier version regarding the speed of particles.
The November full moon has also been referred to by the Tlingit as the digging moon, as it is the time when animals begin to prepare for winter. The Cree have called this lunar event the frost moon, and the Anishinaabe have referred to it as the freezing moon since cold winter temperatures are near
I dont get much out of the source-article; is he asking to forbid astrophotography? oh, seems he asked the opposite and seeks acknowledgement for astrophotography as a useful tool.
