• atx_aquarian@lemmy.worldEnglish
    6·
    1 year ago

    Based on one of your comments clarifying what you’re wondering, I don’t know that this helps you in what you’re looking for, but the “OMG particle” came to my mind. It was traveling at such high energy when it hit our atmosphere that…

    If the proton originated from a distance of 1.5 billion light years, it would take approximately 1.71 days in the reference frame of the proton to travel that distance.

    …

    The energy of the particle was some 40 million times that of the highest-energy protons that have been produced in any terrestrial particle accelerator.

    …

    In the center-of-mass frame of reference (which moved at almost the speed of light in our frame of reference), the products of the collision [with a particle in our atmosphere ] would therefore have had around 2900 TeV of energy, enough to transform the nucleus into many particles, moving apart at almost the speed of light even in this center-of-mass frame of reference. As with other cosmic rays, this generated a cascade of relativistic particles as the particles interacted with other nuclei.

    I don’t know if that cascade is the same as the Cherenkov radiation it produced, but that radiation is how they detected this particle, and it’s interesting a.f.

    [It is] emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity (speed of propagation of a wavefront in a medium) of light in that medium. … Its cause is similar to the cause of a sonic boom…

    I.e., (layman’s understanding here) the particle, having a dual particle- and wave-like nature, is propagating through the vacuum of space “close” to the max speed of propagation of causality itself. As it encounters a medium, our atmosphere, it is going faster than causality itself can possibly propagate through that medium. But the energy is still there and isn’t going to just vanish, so it has to split out into multiple particles that would, with their fraction of the original energy, then be able to propagate through the medium. Or something amazing like that?

    Edit: My layman’s understanding of Cherenkov radiation requires a bigger disclaimer, like a strike-through. :)

    • Cosmicomical@lemmy.worldEnglish
      2·
      1 year ago

      I have never heard that causality slows down in a medium. I understand the use of “speed of causality” to refer to the speed of light in a vacuum, and while I’m aware that light slows down in air, water, etc I’m not sure it has ever been shown that causality itself slows down. My understanding is that also light slows down just because it’s captured and re-emitted by other particles. Though I would be happy to learn something new if my understanding is wrong.

      That said, the OMG particle stuff was very interesting, thank you for sharing.