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Comment by snowwrestler | Hacker News Reader

There is one more complimentary answer, which is that the night sky is not as dark as it seems, but our eyes cannot see all the wavelengths of light that populate the night sky.

If we could see deep into the infrared, we might see more faraway stars and galaxies, whose light has been red-shifted by the expansion of space.

If we could see wavelengths in the single cm range, we might perceive a dim uniform glow in the night sky: the cosmic background radiation.

If we could see radio waves we might see all sorts of light sources in the night sky.

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Yep, explained here: http://www.physics.org/facts/sand-dark.asp

Of course, if there were an infinite amount of light (visible or not) reaching Earth, you'd be dead.

Suppose that the Energy distribution for a certain amount of light (as seen by earth) was given by

          /- 1 if f < f0  
   E(f) = >
          \- 1/f^2 if f > f0

Then we would have light "at all frequencies" which could be said to be "an infiinite amount of light" but the total amount of energy would still be finite.

Most of these explanations don't seem to first figure out whether if you had a uniform distribution of stars (at discrete points) in an infinite (Euclidean) space, if the amount of radiated energy seen at an arbitrary point would diverge if you summed over all available frequencies. If it doesn't, it seems like lack of sensitivity is the main issue here, and the cosmological arguments are simply additional reasons for why it doesn't happen.

Pity someone down-voted you.

From what I take it, you were basically simply asking, "what if the 'infinite amount' at 'all frequencies' were reaching you in a non-uniform distribution of frequencies? - would the original arguments and premises still stand?"

This assumes a minimum energy from each photon. If you could red-shift indefinitely you could end up with ex: 1 + 1/2 + 1/4 + 1/8 +... which sums to 2.

I believe the minimum energy of a photon is directly bound by the age of the universe, so if the universe was twice as old you could have photons at 1/2 the energy. You do get more light sources as you increase distance, but the inverse square law balances that. So Sum (1/n) from 1 to N which really slowly grows to infinity. As in 10^100 = 230.84

I thought this was the obvious answer.

The sky is not dark at night when you use the right telescope. So either the sky changes when you point a telescope at it, or the 'sky' as we see it, is just an artefact of what our primitive eyes and mammalian brain sees.

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