**EARTH SCIENCE**

**Earth Statistics**

The Earth can be described mathematically as a spherical object with the following parameters:

Average radius:

Equatorial circumference:

Volume:

Mass:

Average density:

The Earth's interior is divided into three parts: the crust, the mantle, and the core. The Earth's crust is 6 km deep under the oceans but about 30 km deep under land. Its mantle extends from 30 km to 2900 km; and its core extends from 2900 km to 6378 km, which is the center of the Earth.

Maximum depth of crust:

Maximum depth of mantle:

The interior temperature of the Earth rises steadily from the Earth's surface to its center. The temperature reaches 6000^{o}C near the center of the Earth.

The Earth is not a perfect sphere; it is flattened out at its poles as a result of rotation. Hence, the radius of the Earth varies with position.

Equatorial radius:

Polar radius:

The Earth rotates around the Sun in an elliptical orbit.

Average Earth-Sun distance:

Average orbital speed:

Average centripetal acceleration:

Rotational period:

in mean sidereal time:

in mean solar time:

Rate of rotation: