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Terrestrial planet

Earth

The blue planet

Earth is the third planet from the Sun and the only world known to harbor life. About 71% of its surface is covered by liquid water, which gives Earth its famous blue color from space. A protective atmosphere rich in nitrogen and oxygen, a magnetic field that deflects harmful solar particles, and a stable distance from the Sun all combine to make Earth habitable. It is the largest of the four rocky inner planets.

Quick facts

Distance from Sun
150 million km (1 AU)
Diameter
12,742 km
Day length
24 hours
Year length
365.25 days
Moons
1 (the Moon)
Avg. temperature
15 C

What's it like there?

Earth is the reference point for every other world: mild average temperatures, breathable air, liquid water oceans, and weather driven by sunlight and a dynamic atmosphere. Its surface is constantly reshaped by plate tectonics, volcanoes, erosion, and life itself. Earth is the only planet where water is stable in all three states — solid ice, liquid oceans, and atmospheric vapor — a key ingredient in its ability to support millions of species.

Fun facts

  • Earth is the only planet not named after a Greek or Roman deity.

  • Earth is the densest planet in the solar system.

  • Earth's rotation is gradually slowing by about 1.7 milliseconds per century.

  • The highest point from the center of Earth is not Everest but Mount Chimborazo, due to the equatorial bulge.

  • Around 3,000 tonnes of cosmic dust falls to Earth every year.

Exploration history

  1. Sputnik 1 1957

    First artificial satellite to orbit Earth.

  2. Apollo 8 1968

    First crewed mission to see the whole Earth from lunar orbit ("Earthrise").

  3. Earth Observing System 1999+

    NASA satellite fleet continuously monitoring climate, oceans, and land.

Scientific Sources & Provenance

All data is verified against official space agency records (NASA, ESA, and IAU).