ICRAR: Ten Trillionths of Your Suntan Comes from Beyond Our Galaxy

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bystander
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ICRAR: Ten Trillionths of Your Suntan Comes from Beyond Our Galaxy

Post by bystander » Fri Aug 12, 2016 5:16 pm

Ten Trillionths of Your Suntan Comes from Beyond Our Galaxy
International Centre for Radio Astronomy Research (ICRAR) | 2016 Aug 11

Lie on the beach this summer and your body will be bombarded by about sextillion photons of light per second.

Most of these photons, or small packets of energy, originate from the Sun but a very small fraction have travelled across the Universe for billions of years before ending their existence when they collide with your skin. ...

Where Your Summer Suntan Comes From:
  • Sun:
    • 1x1021 photons per square metre per second
    Reflected off the sky:
    • 3x1020 photons per square metre per second
    Leftover from the Big Bang:
    • 1x1016 photons per square metre per second
    Reflected off dust in the solar system:
    • 1x1014 photons per square metre per second
    Extragalactic background light:
    • 1x1010 photons per square metre per second
Extra-galactic background light measurements from the far-UV to the far-IR
from deep ground and space-based galaxy counts
- Simon P. Driver et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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neufer
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Re: ICRAR: Ten Trillionths of Your Suntan Comes from Beyond Our Galaxy

Post by neufer » Fri Aug 12, 2016 6:53 pm

bystander wrote:Ten Trillionths of Your Suntan Comes from Beyond Our Galaxy
International Centre for Radio Astronomy Research (ICRAR) | 2016 Aug 11
Lie on the beach this summer and your body will be bombarded by about sextillion photons of light per second.

Most of these photons, or small packets of energy, originate from the Sun but a very small fraction have travelled across the Universe for billions of years before ending their existence when they collide with your skin. ...

Where Your Summer Suntan Comes From:
  • Sun:
    • 1x1021 photons per square metre per second
    Reflected off the sky:
    • 3x1020 photons per square metre per second
    Leftover from the Big Bang:
    • 1x1016 photons per square metre per second
    Reflected off dust in the solar system:
    • 1x1014 photons per square metre per second
    Extragalactic background light:
    • 1x1010 photons per square metre per second
My back of the envelope calculation shows the TOTAL # of photons as:
  • Sun:
    • 1x1022 photons per square metre per second
    Black Body radiation off the ground (to compensate):
    • 2x1023 photons per square metre per second
    Leftover from the Big Bang (~100 times colder than ground):
    • 2x1017 photons per square metre per second
I can sort of believe that perhaps 1 in 10 Solar photons are capable of producing a suntan.

But I can NOT believe that 1 in 20 Big Bang photons are capable of producing a suntan :!:
  • (Nor are 1 in 2 million Big Bang photons capable of producing a suntan.)
Art Neuendorffer