As confusion elsewhere on this page illustrates, one also needs to clarify absorption. "It's just blue" sky and "it's just blue" stained-glass have quite different behavior. Both side scatter some blue, but while one mostly transmits the rest, the other mostly absorbs the rest, for very different experiences peering through it.
replySo perhaps "clear with a blue tint"?
Yes, I came here to say this. The whole topic drives me crazy. Air is just blue. Everything is a color because of some physics reason. Some birds have blue wings due to microscopic structures and how light interacts with them, rather than pigment.
replyIf you took a large column of air into space and shined white light through it, it would be blue.
No, it would look red. The weird thing about air is that it's not reflection or absorption that gives the color, but scattering, and that means the color is strongly dependent on what direction you are looking at it from in a way that most transparent mediums aren't.
replyOk, so the air would be red from one angle, blue from another. In each case, that is what color the air “really” is, in the same sense that a butterfly’s wings are blue (but not from every angle)
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