# Is the sunlight reflected off of either the atmosphere or surface of a planet polarized?

Is the reflecting off of the surface of the terrestrial planets (those with or without an atmosphere), or the gas- or ice-giants, polarized, or unpolarized like the sunlight before it is reflected?

• It's really hard to make non-normal reflection completely unpolarized or completely polarized, so the answer is going to be "ya, somewhat, depending." Can you explain why this question is related to Space Exploration in some way? It's a great fit in Astronomy SE, but a one-sentence question about the interaction of light with rock, gas, and aerosols doesn't seem to have any Space Exploration aspects at all.
– uhoh
Mar 23 '20 at 0:53
• Also, for the latter two see the polarization aspects of Rayleigh scattering and Mie scattering/
– uhoh
Mar 23 '20 at 0:56
• @uhoh I was thinking it fit under planetary sciences, but I forgot to include the tag. Mar 23 '20 at 3:14

The answer is "it's complicated." If you start with Snell's Law(s) , they show that the degree of polarization at an interface depends both on the ratio $$\frac{n_2}{n_1}$$ and on the angle of incidence.