Ask someone what causes the seasons to change, and you'll very often get the wrong answer.

Could it be that in winter Earth is farther away from the sun, and in the summer it is closer? People living on the other side of the planet wouldn't agree with that, since winter in the Northern Hemisphere is summer in the Southern Hemisphere.

The truth is that Earth's orbit around the sun is nearly circular. Earth's distance from the sun doesn't account for much of the difference in the seasonal variations in climate.

So what could be causing the seasons?