Our home. The only world known to host life, with liquid water oceans covering 71% of its surface and a protective magnetic field.
Earth, the only world known to host life. Image: NASA
Distance
1 AU (150 M km)
Diameter
12,742 km
Year
365.25 days
Day
24 hours
Moons
1
About Earth
Earth is the largest of the four rocky planets and the only one with plate tectonics, liquid surface water and an oxygen-rich atmosphere. Its molten iron outer core generates a magnetic field that shields the surface from the solar wind. The Moon, unusually large relative to its planet, stabilises Earth's axial tilt and drives the tides. Earth formed about 4.54 billion years ago, and life appeared within its first billion years.
Only known world with life
Densest planet in the Solar System
Axial tilt of 23.4° gives us the seasons
Moons
Name
Diameter
Notes
The Moon
3,475 km
Earth's only natural satellite, and the fifth largest moon in the Solar System. Its gravity drives the tides, and it is the only other world humans have walked on, during the Apollo missions from 1969 to 1972.
In pictures
The MoonThe Moon photographed by the Galileo spacecraft as it passed Earth on its way to Jupiter.NASA/JPL/USGSEarthriseEarth rising over the Moon, photographed by Bill Anders from lunar orbit on Christmas Eve 1968 during Apollo 8.NASA/JSCTranquility BaseBuzz Aldrin on the Moon, photographed by Neil Armstrong during Apollo 11 in July 1969.NASA/JSCPale Blue DotEarth is the speck in the sunbeam, photographed by Voyager 1 from about 6 billion km away in 1990.NASA/JPL-CaltechAurora from orbitAn aurora glowing beneath the International Space Station.NASA/JSC
