The other day I saw a green light emitted from some source far away, and I realised that if I looked at it out of the corner of my eye I perceived it completely white. What is the explanation for this? Should this be more of a biology of the human eye question perhaps?
Take a look at https://xkcd.com/1080/large/. Red and green-sensing cones are mostly found in the center of your visual field. Interestingly, this is not true for blue-sensing cones. It's also not true for rods, which detect black-and-white, so the reason the light appeared white is likely that it was picked up mostly by rods.