Over 19,000 – 24,000 years, the direction of Earth’s tilt shifts (spins). Over approximately 100,000 – 400,000 years, gravitational forces slowly change Earth’s orbit between more circular and elliptical shapes, as indicated by the blue and yellow dashed ovals in the figure to the right.

Over long periods of time, the gravitational pull of other members of our solar system slowly change Earth’s spin, tilt, and orbit. As the Earth orbits the Sun, the Earth is pulled by the gravitational forces of the Sun, Moon, and large planets in the solar system, primarily Jupiter and Saturn.

Daily changes in light and temperature are caused by the rotation of the Earth, and seasonal changes are caused by the tilt of the Earth.