Do different parts of the world receive different amounts of sunshine during the year? Ignore clouds, or consider only what is received either on the cloud tops or surface, whichever is available. Is it the same at the poles as at the equator? ... the northern and the southern hemispheres?

Consider two interpretations of the above: (1) number of hours per year that the sun is up, (2) the total insolation (total solar energy received per unit of area of the ground) received during the year, weaker when the sun is low near the horizon than when it is high in the sky.

(In reply to re: Unscientific solution by Cory Taylor)

Cory, I disagree that the period of time when the sun never rises is more than twice the period when it never sets. While that may be true if you compare, say, 75N lat. with 85S lat., it cannot be true for a northern and southern latitude equidistant from the equator. Consider a horizontal beam of light hitting a globe spinning with its axis tilted 23.5 degrees. If the 75N lat. line is continuously in shadow, the entire 75S lat. line will be in the light. It's a matter of symmetry.

Posted by Bryan on 2003-03-10 09:51:53