Sunday, September 22, 2013

Science Lesson: Autumn Equinox

Today is the Autumn Equinox, and that means it is the first day of fall. On the equinox, the sun's rays fall directly onto the equator perpendicular to the earth. As a result, sunlight covers the earth equally from north to south pole (the same thing happens on the Spring Equinox). All over the world, day and night are the same length (12 hours) and the sun will set at due west on the horizon and rise due east.

As time moves forward heading to the Winter Solstice, which usually occurs around December 21st, the days in the northern hemisphere will begin to get shorter and the nights will get longer by about a minute every day. The opposite will happen in the southern hemisphere. Then it will reverse after the Winter Solstice and the days will get longer in the northern hemisphere until the Summer Solstice, which occurs usually around June 21st. This is what causes the seasons.

No comments:

Post a Comment


Related Posts Plugin for WordPress, Blogger...