If neutrinos are everywhere, why isn't Cherenkov's Radiation?

  1. Why isn't all water being infiltrated by neutrinos and giving off a blue glow?

    P.S: I know they're not literally everywhere.
  2. jcsd
  3. mathman

    mathman 6,754
    Science Advisor
    Gold Member

    There is no interaction (almost) between the neutrinos and water. More important, they are uncharged.
  4. Neutrinos react very weakly with ordinary matter and usually pass through virtually unaffected.

  5. Did not realize this volume:

  6. Actually, they ARE, pretty much. See the post directly above.

  7. So is this video completely wrong then?!
    Last edited by a moderator: Sep 25, 2014
  8. No. The Cerenkov radiation only happens when a neutrino actually interacts with another particle, and comes from an electron given off by the interaction that moves faster than light in the water. These interactions are very rare. All water would give off occasional blue glows, but so few they're not noticeable without special detectors.
  9. The standard understanding of Cherenkov radiation is that it is produced when a (electrically) CHARGED particle passes through a medium at a speed faster the the speed of light in that medium. So neutrinos do not produce this type of radiation simply because they are not charged.

    Interestingly however one of the more favoured arguments for why the supposed observation of superluminal neutrinos by the OPERA experiment is wrong is the argument by Cohen and Glashow that if neutrinos did move superluminally they would then emit a kind of cherenkov radiation and thus lose energy and would therefore not arrive at the OPERA experiment with the observed energy. However note that this is not really the same as cherenkov radiation as the dominant radiation is to electron-positron pairs. The details of all this are in the original short paper http://arxiv.org/abs/1109.6562 and also there is a really nice review of all this by Matt Strassler here.
  10. Could you put a really good telescope in the deep ocean and detect it? If it's deep enough wouldn't photons/cosmic rays/etc be blocked leaving only neutrinos? Volcanoes and strange glowing creatures might be a problem. Could they be avoided?

    Google search shows I'm not quite as dumb as I think I am:


    And this:


    Interesting stuff!
  11. ZapperZ

    ZapperZ 30,744
    Staff Emeritus
    Science Advisor
    Education Advisor

    But one also needs to consider the logistic when designing an experiment, and also one other important factor: how much it will cost! If we live in an ideal world, I can easily tell you a bunch of amazing experiments that we can do. But we are not living in that world.

    For example, the DUESL lab at the Homestake mine is already having issues with getting funding for LBNL experiment. And this is in a place that's already built (pre-existing mine deep underground) with some existing infrastructure. Think of the hurdle to do such a thing in some place new.

  12. Actually, they're doing a not-all-that-dissimilar experiment at the south pole, but using a stretch of ice-cap rather than liquid water. See http://icecube.wisc.edu/.
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