Home » Nature » Earth & Solar Geometry, Celestial Mechanics – Pictures Explain

Earth & Solar Geometry, Celestial Mechanics – Pictures Explain

Earth & Solar Geometry, Celestial Mechanics

The geometrical relationship between the earth and sun is responsible for the earth’s climates.

The two principal movements of the earth are rotation and revolution.

Seasons & Daylength

Without the inclination of the earth there would be no seasons.

Daylength would be exactly 12 hr light and 12 hr dark except at 0º when the sun would always be at the horizon.

At Lafayette Indiana the sun would be always 40º from the zenith (directly overhead) at noon.

Seasonal time (solstice and equinox) is based on the geometry of the earth in relation to the sun during its yearly revolution.

Solstice. The date the sun stands still on its N-S migration.

Because of the inclination of the earth’s axis the sun at its zenith is directly overhead at 23.5º N on June 21 (the summer solstice) and directly overhead at 23.5º S on December 21 (Winter solstice).

Equinox. Refers to date of equal night and day period.

This is the date when the sun at noon is directly overhead at the equator (March 21 = vernal equinox in the N hemisphere and September 23 = autumnal equinox in the N hemisphere)

http://www.hort.purdue.edu/newcrop/tropical/lecture_02/lec_02.html

You must be logged in to post a comment Login