# How do we know that light isn't redshifted by space itself? [duplicate]

Do we know if light is red-shifted by traveling through space? If it isn't, how do we know? I guess my pondering has lead me to wonder if the observed accelerating space-expansion is a misinterpretation. If light is red-shifted by traveling through space, we may be able to re-interpret Hubble's equation (I know, that might be heresy) as

$redshift = SomeConstant*d$ which would imply that distant objects aren't necessarily accelerating, the light we view is increasingly redshifted for more distance objects, independent of them moving away from us. Then, maybe we don't need dark energy anymore.?.

## marked as duplicate by knzhou, ZeroTheHero, Kyle Kanos, Jon Custer, user191954 Feb 28 at 13:36

• @BillAlsept I think there are various proposed mechanisms: scattering I think fails as it would cause distant objects to be blurred, which they aren't in fact. If $E=h\nu$ is correct then there must be a big question about where the energy goes, which is very easily answered by recession, and it's hard to see what the tired light story about that would be. – tfb Feb 23 '16 at 9:20