Did you ever wonder why we have the changing seasons in North and South America. If you did I will try to give a simple as possible scientific explanation of what is happening.
The Earth is in constant motion. It is spinning on it's axis which is tilted at 23.5 degrees. It turns one rotation in 24 hours so you are facing the Sun for approximately 12 hours a day. The earth is also rotating around the Sun. It keeps a circular motion around the Sun because of the gravitational pull of the Sun on the Earth. It takes a year for the earth to travel around the Sun. The circular motion and the tilt is what causes the change of seasons.
We have four main position in relationship to the Sun. In the spring (March 21 this year) you have what is called the Vernal Equinox. The Sun shines on the earth and the tilt of the Earth is of no effect. The Sun shines on the Northern and Southern Hemispheres equally. This is the beginning of Spring.
As the earth continues around the Sun the tilt of the earth comes into effect and as the earth moves 1/4 of the way around the sun until the earth's tilt is at 23.5 degrees and the Sun shines more on the Northern Hemisphere. This takes place on the first day of Summer (June 21 this year) at the Summer Solstice. This is the beginning of Summer. This is the longest day of the year for us.
The Earth then continues 1/2 of the way around the Sun. In the Fall (September 23 this year) you have what is call the Autumnal Equinox. The Sun shines on the earth and the the tilt of the Earth again has no effect. The Sun shines on the Northern and Southern Hemispheres of the earth equally. This is the beginning of Fall.
As the earth continues around the Sun the tilt of the earth comes into effect and the earth moves 3/4 of the way around the Sun until the earth's tilt is at 23.5 degrees and the Sun shines more on the Southern Hemisphere. This takes place on the first day of Winter (December 22 this year) at the Winter Solstice. This is the beginning of Winter. This is the shortest day of the year for us.
The earth continues the final 1/4 of the way around the Sun and the cycle is ready to begin again. The Southern Hemisphere is going into Summer now as we go into Winter. This should explain the changing seasons throughout the year.
1 comment:
This is fascinating, and information I didn't know. It's a very good explanation too.
By the way, I'm still downtown and have access, so I'm trying to catch up on your blog before I have to leave.
Post a Comment