Question: Why is the sky blue?
Answer: Because that's what it looks like.
Philip has been exercised by this question. It turns out that the standard response, to do with the dependence of scattering intensity on wavelength, actually comes up with the answer "It isn't; it's purple".
But interestingly, our eyes are more sensitive to blue light than purple, and so the sky only appears blue. This fascinates me in much the same way that no two people ever perceive the same rainbow (for certain values of 'same'). Our reality is indeed influenced if not determined by our perception.
Comments
I tend to find the sky looks a bit more purple above 3500m, so I would think the scattering of light in the lower troposphere probably plays a greater role. But that's just me, of course...
Posted by: MG | May 19, 2007 01:37 PM
Very interesting. And of course there's the sex difference because the "red cone gene" as I once it horribly described, is X-linked. one would assume my pale blue is a lot deeper through female or Klinefelter eyes...and congrats on the Nature pick-up. All publicity is good publicity. Although, as you yourself have opined frequently, no one reads blogs anyway >:)
Posted by: tideliar | May 22, 2007 07:16 AM