6 ms·

I wish the article included a bit more info about the significance of the particle, instead of just describing how energetic it was. For example, it never expan

I wish the article included a bit more info about the significance of the particle, instead of just describing how energetic it was. For example, it never expands on this, which is IMO the most interesting sentence on the page: > The particle's energy was unexpected and called into question theories of that era about the origin and propagation of cosmic rays.

brucethemoose2 3y ago
Yeah... It makes more sense when this article is linked from other Wikipedia pages. See the linked article: > The Greisen–Zatsepin–Kuzmin limit (GZK limit or GZK cutoff) is a theoretical upper limit on the energy of cosmic ray protons traveling from other galaxies through the intergalactic medium to our galaxy. The limit is 5×1019 eV (50 EeV), or about 8 joules (the energy of a proton travelling at ≈ 99.99999999999999999998% the speed of light). The limit is set by the slowing effect of interactions of the protons with the microwave background radiation over long distances (≈ 160 million light-years). The very highest energy cosmic rays are theorized to come from Active Galactic Nuclei (very hot stuff around the giant black hole at the center of galaxies) or supernovae (large exploding stars), or even from the magnetic fields of galaxies themselves, all which are mostly outside the Milky Way. The implication is that some of these particles could be coming from smaller, closer sources, close enough to not be slowed by the MBR. This is unusual because it seems like closer phenomenon shouldn't be able to accelerate a proton that much.
- simonh 3y ago
  Some black holes spin at more than 90% the speed of light. Shock waves driven by magnetic fields in the plasma close to the event horizon would probably do it.
- twic 3y ago
  8 joules is the kinetic energy of a British one-penny coin travelling at 150 miles per hour. You'd feel that!
  - huytersd 3y ago
    That’s so insane to think about a single proton feeling like a bullet fired at you!
    - deleted 3y ago
      [deleted]

brucethemoose2 3y ago

Yeah... It makes more sense when this article is linked from other Wikipedia pages. See the linked article: > The Greisen–Zatsepin–Kuzmin limit (GZK limit or GZK cutoff) is a theoretical upper limit on the energy of cosmic ray protons traveling from other galaxies through the intergalactic medium to our galaxy. The limit is 5×1019 eV (50 EeV), or about 8 joules (the energy of a proton travelling at ≈ 99.99999999999999999998% the speed of light). The limit is set by the slowing effect of interactions of the protons with the microwave background radiation over long distances (≈ 160 million light-years). The very highest energy cosmic rays are theorized to come from Active Galactic Nuclei (very hot stuff around the giant black hole at the center of galaxies) or supernovae (large exploding stars), or even from the magnetic fields of galaxies themselves, all which are mostly outside the Milky Way. The implication is that some of these particles could be coming from smaller, closer sources, close enough to not be slowed by the MBR. This is unusual because it seems like closer phenomenon shouldn't be able to accelerate a proton that much.

simonh 3y ago
Some black holes spin at more than 90% the speed of light. Shock waves driven by magnetic fields in the plasma close to the event horizon would probably do it.
twic 3y ago
8 joules is the kinetic energy of a British one-penny coin travelling at 150 miles per hour. You'd feel that!
- huytersd 3y ago
  That’s so insane to think about a single proton feeling like a bullet fired at you!
  - deleted 3y ago
    [deleted]