On the question of snow or clouds: I have also heard that the flourescence
from UV
light enhances the blue end of the spectrum (when you shine UV on "white"
things,
they glow blue), thus making the "yellow" light from the sun look "white".
The
argument goes that if the sun really were "white", the extra component
from the
UV-reaction would make white things like snow or clouds look blue. In
order to
take this effect into account, the original solar color would have to seem
slightly
redder than white, hence yellow.
This argument is not refuted by the articles at the scientific blogging
link, because
he was still looking at an unfiltered image of the sun on a white surface,
so the
UV effect would still have been present. Has anyone ever looked at an
image of the
sun on a "white" surface with the UV filtered out? Is it still white?