I was thinking about why the poles are colder and I came out with three possible explanations.
1. The atmosphere blocks light beams coming to poles
The Sun is seen only slightly over the horizon at the poles, so the light beams have longer way to the poles. If only this case were true, then the total difference between the poles and the equator would be the same as the energy that was absorbed by the atmosphere.
2. Sun is only slightly over the horizon at the poles.
Poles are often in shadow of the parts of the Earth which are closer to the equator.
3. Poles are farther from the Sun
The longer is the way to Sun the lower is the chance to catch a light from the Sun.
Please, correct me wherever I'm wrong. I'd like to know
Which of these three is most correct?
How significant are the described effects of the other explanations?