Below is a picture of a typical sunset that I have been observing lately at an undisclosed location in the Southern Hemisphere:

enter image description here

Given that the base of the picture is parallel to sea level, you can see that the line where the dark blue meets the red in the sky, is on an angle of elevation of approximately 7 - 8 degrees.

Is there an explanation for this phenomenon (which I have observed for the past few days) and is it related to my position on the Earth, or the time of year?

  • $\begingroup$ It makes some sense, given the incidence angle of the rays with the atmosphere would vary according to season a latitude. No idea where I would confirm this. Physicist, maybe? $\endgroup$
    – mtb-za
    Commented May 8, 2015 at 5:36
  • $\begingroup$ Which direction are you looking? Towards the setting sun, or at an angle? $\endgroup$ Commented May 11, 2015 at 7:44
  • $\begingroup$ Hill shadows? Is it the same if you move a few kilometers north or south? $\endgroup$
    – naught101
    Commented Apr 7, 2016 at 3:45

1 Answer 1


Looking at your picture I would say it was most likely not taken facing in the direction of the setting sun, but perpendicular to it. What you see as a colour gradient is most likely the shadow of the Earth. I suspect if you took a series of pictures you'd see the shadow (your gradient) moving upwards and becoming steeper while the sun sets deeper behind the horizon.


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