Expert: Paul Wagner - 11/8/2011

Question
I was asked to explain this phenomenon, why is it that as the sun is setting, or rising, it appeared to be much faster with relative to other times of the day. I was told that the sun rises and sets past the horizon in a matter of minutes while the other part of the day, the sun seems to be moving at a very slow rate. Please enlighten me. Thanks.

Answer
Hi Jack

It's because there is nothing in the middle of the sky to measure the sun's speed against.  If you lie down in the shade of a tree, and watch the sun, you will see that it moves quite noticeably.  But usually we see the sun with nothing near it, and so we don't notice the movement.

When it is on the horizon, the movement is obvious because the horizon gives us a point of reference.

Paul Wagner