Posted by Davin Flateau on 22 Sep 2005 at 12:00 am.
Filed under Event.
Fall officially beings with the autumnal equinox today at 5:32 p.m.
Since the summer solstice back in June when it reached its highest (northmost) point in the sky at noon, the sun has been slowly moving lower in the sky. Today, the sun has reached the celestial equator.
The sun rises directly in the east and sets directly in the west, and the amount of daylight and night are equal. The sun will continue to get lower (southward) in the sky until the winter solstice on December 21, where it reaches its lowest point, and begins to rise again.
This solar dance in our sky is due to the 23.5 degree tilt of the earth’s pole with respect to our orbit around the sun. As we orbit around the sun during the year, the tilt points certain parts of the earth “toward” the sun or “away” from the sun, resulting in different parts of the earth receiving more solar energy for a given surface area than other parts of the earth. This causes the seasons we experience during the year.
