Nutation is a small cyclical motion superimposed upon the steady 26,000-year precession of the Earth's axis of rotation. It is mainly caused by the gravitational effect of the 18.6-year rotation period of the Moon's orbit. The main...

Discover interesting facts about Earth's partner, the moon, which is more like a double planet than a planet and a moon.

Discover 10 interesting things about Earth, including its shape, its seasons, rotation, Ice Ages, the Atacama Desert, gravity, changing sea levels, and the Moon.

Learn how Greek mathematician Eratosthenes used geometry to estimate the circumference of the Earth.

The concept of jet streams is explained on this site. Read about why jet stream winds blow from west to east, what the polar jet and subtropical jet are, the role that the rotation of the Earth plays, etc.

[Free Registration/Login Required] This Article-A-Day-Set provides six articles related to "time." Students will learn about the days of the week and months of the year.