Sun & planets · Space Codex
Earth
The densest planet and the only one known with stable surface oceans, active plate tectonics and life.
The only known world with life
At a glance
Key points
A strong magnetic field shields its atmosphere from the solar wind.
- The densest planet in the Solar System
- The inner core is about as hot as the Sun's surface
- Sunlight reaching you left the Sun 8.3 minutes ago
Interior
A solid iron-nickel inner core 1,221 km in radius, roughly as hot as the Sun's surface, sits inside a 2,300 km-thick liquid outer core whose churning generates the magnetic field. Above that lie 2,900 km of slowly convecting mantle and a crust only about 5 km thick under the oceans and 30 km under the continents.
Atmosphere and climate
Nitrogen and oxygen make up 99% of the air, but trace gases such as water vapour and CO₂ keep the average surface near 15 °C instead of the −18 °C a bare rock at this distance would have. Oceans hold 97% of the planet's water and move heat from the tropics to the poles.
Surface
Plate tectonics recycles the crust: oceanic plates are rarely older than 200 million years, while some continental rocks are four billion years old. No other known planet has this conveyor belt.
From space
City lights trace human settlement on the night side, and auroras ring the magnetic poles in ovals between about 60° and 75° latitude when solar storms arrive.
What we still don't know
When plate tectonics began, how life first started, and whether planets like Earth are common around other stars.
Moons
Earth's moon has its own sourced entry.
- The MoonEarth's only natural satellite
Missions
- 1998–
Continuously crewed since Nov 2000, about 400 km above Earth.
- 2021–
Infrared observatory at Sun–Earth L2, about 1.5 million km from Earth.
First-hand · our 3D model
How we render it
Earth carries the most layers in the model. The day map, a separate cloud deck and a night map of city lights are blended per pixel. Clouds cast shadows projected along the sunlight onto the ground, and sunlight passing through the air reddens towards the terminator. City lights fade in through civil and nautical twilight and dim under clouds. Oceans come from a real land and water mask, with a specular glint tuned to water (reflectance 0.020, roughness 0.44).
The atmosphere is a ray-marched single-scattering shell with Rayleigh, Mie and ozone terms, sampled 16 times per pixel on Explore. Aurora curtains sit on ovals around the geomagnetic pole (80.65°N 72.68°W) and its antipode: about 67° latitude at magnetic midnight and 75° at noon, with green 557.7 nm emission at the base, red 630.0 nm at the top and a faint blue 427.8 nm lower edge. The globe is tilted 23.4°.
Sizes and distances in the model are not to scale, so every world can be seen up close. Colour maps are derived from NASA mission imagery via Solar System Scope (CC BY 4.0). The first frame uses light startup maps; higher-resolution maps stream in after the scene is on screen, decoded off the main thread so the page stays responsive.
Related entries
- The MoonEarth's only natural satellite
- Artemis programmeNASA's return to the Moon
Sources
- JPL Solar System Dynamics: planetary physical parameters (opens in a new tab)
- NASA NSSDC Planetary Fact Sheet (opens in a new tab)
- NASA NSSDC Earth Fact Sheet (opens in a new tab)
- NASA Science: Earth facts (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.