Revolution & Seasons

Dolphins sleep with one eye open! Fact: Dolphins sleep with one eye open!

Is the movement of the earth around the sun. Revolution Is the movement of the earth around the sun.

Earth travels at 67,000 mph in it orbit! The earth does not orbit the sun in a perfect circle. It is oval or elliptical. Earth travels at 67,000 mph in it orbit!

Aphelion/Perihelion

The most observable proof that the Earth revolves is the seasons The most observable proof that the Earth revolves is the seasons. But the proof that the Earth in fact does revolve is the parallax shift in the distant stars.

Suns rays striking a non tilted Earth.

B/c of Earth’s tilt (23.5o), the suns rays strike the earth with varying intensities and length.

When the earth is in perihelion the Northern hemisphere is tilted away from the sun. Therefore there is less of the sun’s intensity and time striking the earth. During this time it is winter in the No. Hemisphere.

Tropic of Capricorn 23.5os This is the shortest day of sunlight Winter Solstice: Occurs on Dec. 21/22. The suns rays strike the earth at 90o along the Tropic of Capricorn 23.5os This is the shortest day of sunlight

During aphelion The seasons are the opposite During aphelion The seasons are the opposite. Because the Suns intensity is strongest in the Northern Hemisphere.

This is the longest day of sunlight. Summer Solstice: Occurs on June 21/22. The suns rays are striking the earth at 90o along the Tropic of Cancer 23.5on. This is the longest day of sunlight.

This is the beginning of the Spring. Vernal Equinox: Occurs on March 21/22. The suns rays are striking the earth at 90o along the equator. This is the beginning of the Spring.

It is the beginning of fall. Autumnal Equinox: Occurs on Sep. 22/23. The suns rays strike the earth at a 90o along the equator. It is the beginning of fall.

Brain Teaser:

From the beginning of eternity, To the end of time and space, To the beginning of every end, And the end of every place. What am I?