Looking at the Huygens pictures, it was something of a surprise to me that so much sunlight gets through. Does anyone have any good numbers? I'm sure that it would be possible to calculate such numbers from Huygens's data.
And has anyone tried to find out how much sunlight makes it to Titan's surface without being scattered?
At first glance, the shadows of the surface rocks in Huygens's pictures may imply some sizable fraction, but when looking out my room's window at the overcast sky, I have second thoughts.
The sky looks bright, but the Sun cannot be seen behind the clouds. And the sky casts shadows, though rather diffuse ones and not sharp-edged ones.
And my attempts at radiative-transfer calculations show that this is the expected situation when the scattering of light is much greater than the absorption of light -- the light gets scattered out of its initial direction, but persists.
Is that also the case with Titan's atmosphere?
It also seems to be the case with Venus's atmosphere, at least judging from the Venera surface pictures.