How Big Is Earth?
Our planet as seen from space.
Credit: NASA/JPL

Earth, the third planet from the sun, is the fifth largest planet in the solar system; only the gas giants Jupiter, Saturn, Uranus and Neptune are bigger. Earth is the largest of the terrestrial planets of the inner solar system, bigger than Mercury, Venus and Mars.

The radius of Earth at the equator is 3,963 miles (6,378 kilometers), according to NASA's Goddard Space Flight Center. However, Earth is not quite a sphere. The planet's rotation causes it to bulge at the equator. Earth's polar radius is 3,949 miles (6,356 km) — a difference of 14 miles (22 km).

Using those measurements, the equatorial circumference of Earth is about 24,900 miles (40,070 km). However, from pole-to-pole — the meridional circumference — Earth is only 24,812 miles (39,931 km) around. This shape, caused by the flattening at the poles, is called an oblate spheroid.

Earth's density is 5.513 grams per cubic centimeter, according to NASA. Earth is the densest planet in the solar system because of its metallic core and rocky mantle. Jupiter, which is 318 more massive than Earth, is less dense because it is made of gases, such as hydrogen.

Earth's mass is 6.6 sextillion tons (5.9722 x 1024 kilograms). It volume is about 260 billion cubic miles (1 trillion cubic kilometers).

The total surface area of Earth is about 197 million square miles (510 million square km). About 71 percent is covered by water and 29 percent by land.

Mount Everest is the highest place on Earth above sea level, at 29,028 feet (8,848 meters), but it is not the highest point on Earth — that is, the place most distant from the center of the Earth. That distinction belongs to Mount Chimaborazo in the Andes Mountains in Ecuador, according to the National Oceanic and Atmospheric Administration (NOAA). Although Chimaborazo is about 10,000 feet shorter (relative to sea level) than Everest, this mountain is about 6,800 feet (2,073 m) farther into space because of the equatorial bulge.

The lowest point on Earth is Challenger Deep in the Mariana Trench in the western Pacific Ocean, according to the NOAA. It reaches down about 36,200 feet (11,034 meters) below sea level.