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A Neutrino flux at event horizon

  1. Sep 25, 2017 #1
    Hi, Assuming an average Neutrino mass of 2.0 Electron volts how much mass will a black hole with an event horizon the size of the one at the center of our galaxy accrete in a year? I've seen estimates of how many Neutrinos pass through our bodies each second and it seems like the mas would really add up over the surface area of a black hole.

    Cheers,
    Corby
     
  2. jcsd
  3. Sep 25, 2017 #2

    mfb

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    What do you get if you take this neutrino flux and multiply it with the black hole cross section? Compare it to the mass of the black hole.

    2 eV is above the limits from cosmology, by the way. Stellar neutrinos will have most of their energy as kinetic energy and the neutrino mass is irrelevant for them.
     
  4. Sep 26, 2017 #3
    OK use .2 Electron volts, a radius of 13 million kilometers, and an area of 2.12E+17 square Centimeters. If the Neutrino flux is say 1E+11 per square Centimeter then the total Neutrino flux would be 2.12E+28 per second or 6.68E+35 per year. Looks like this only would increase the black holes mass by 238 grams! Of course my values could be way off?
     
  5. Sep 27, 2017 #4

    mfb

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    The neutrino flux is smaller if you are not near a star, but the neutrino energies are higher. Anyway, the mass is completely negligible, even 20 orders of magnitude more wouldn't have a notable effect.
     
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