Why does the revolution of earth around the sun allow us to see predictable patterns in the seasons?

Answer 1

The seasons are just one factor that provides proof that the earth revolves around the sun. The seasons are caused because the earth's axis (or its central revolution point) is tilted 23.5 degrees from a line drawn perpendicular to the plane of the earth's orbit. As the earth completes its yearly cycle around the sun, there are times when the north pole is either tilted towards the sun (during what we call summer in the northern hemisphere), or tilted away from the sun (during winter in the northern hemisphere). At other times, i.e. spring and fall, the axis is generally parallel to the incoming sun's rays.

For a more complete explanation, I've referred to The Gale Encyclopedia of Science, which explains the seasons like this:

"During summer, two effects contribute to produce warmer weather. First, the sun's rays fall more directly on Earth's surface and this results in a stronger heating effect. The second reason for the seasonal temperature differences results from the differences in the amount of daylight hours versus nighttime hours. The sun's rays warm Earth during daylight hours and Earth cools at night by re-radiating heat back into space. This is the major reason for the warmer days of summer and cooler days of winter. The orientation of Earth's axis during summer results in longer periods of daylight and shorter periods of darkness at this time of year. At the mid-northerly latitudes summer days have about 16 hours of warming daylight and only eight hours of cooling nights. During mid-winter the pattern is reversed."

As you can see, Earth's orbit around the sun, and the changing orientation of Earth's axis, are the reason why seasons exist.

I hope this helps! You can access databases like Gale Virtual Reference Library, where I found this answer, through your local library. Many library web sites even have a link where you can chat online with a librarian 24 hours a day, 7 days a week!

Kathryn Benson

Future Librarian and Slam the Boards! participant

University of Texas at Austin

MSIS expected Spring 2013

Source:

"Seasons." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed. Vol. 5. Detroit: Gale, 2008. 3838-3839. Gale Virtual Reference Library. Web. 10 Oct. 2012.