posted on Sep, 24 2012 @ 07:10 AM
Originally posted by NewAgeMan
Why does light, in the vacuum of space follow the inverse square law - what's stopping or limiting the photons according to that law, why don't the
photons just continue on..?
They do continue on. There's just not enough of them reaching a particular point in space at that distance to be detectable. The number of photons
given off by a star is enormous, but its still finite and they're traveling in all directions, not just at your eyeball.
Consider a star just 100 light years away. Think of space at that distance as a sphere around the star (a sphere, since any given photon can be
emitted in any direction from the star). What percentage of the surface area of that sphere does the side of the Earth facing that star consist of?
And what about your eyeball? Its ridiculously tiny. That star has to emit an absolutely insane number of photons just to hit the Earth with one of
them, and far, far more to actually hit your eye. What are the odds of that happening for a star or even a galaxy a billion light years away?
There's the problem. Those photons are still there, but since they can be emitted in any direction from the star, they're spread out over an
enormous area, and the odds of them hitting your eye are ridiculously small. There's not enough of them that make it to your eye to activate the
light receptors in your retina.
edit on 24-9-2012 by vor78 because: (no reason given)
edit on 24-9-2012 by vor78 because: (no