Earth
3rd planet from the Sun · The Blue Marble · Our Home
Terrestrial
Habitable
1 Moon
12,742
Diameter (km)
365.25
Days / Year
1 AU
From Sun
~8B
Population
The Moon (Luna)
Earth's only natural satellite — the 5th largest moon in the solar system and the only other world humans have walked on.
Diameter
3,474 km
~27% of Earth
Orbital Period
27.3 days
Tidally locked
Surface Gravity
1.62 m/s²
1/6 of Earth's
Formation
~4.5 Billion yrs
Giant impact theory
🌊 Did you know? The Moon is slowly drifting away from Earth at ~3.8 cm per year — about the rate your fingernails grow!
Key Exploration Missions
🛸
Sputnik 1 · USSR
1957 — First artificial satellite to orbit Earth
👨🚀
Vostok 1 · USSR
1961 — Yuri Gagarin, first human in space
🌕
Apollo 11 · NASA
1969 — First humans to walk on the Moon
🛰️
Landsat Program · NASA/USGS
1972–present — Continuous Earth observation since 1972
🔭
Hubble Space Telescope · NASA/ESA
1990–present — Orbiting Earth, revolutionized astronomy
🏠
ISS · Multi-agency
1998–present — Continuously crewed since Nov 2000
🌙
Artemis Program · NASA
2022–future — Return humans to the Moon, step to Mars
💧
71% Covered in Water
Earth is the only known planet with liquid water on its surface — hence the nickname "The Blue Marble."
🌿
Oxygen-Rich Atmosphere
78% Nitrogen, 21% Oxygen, 1% other. This unique mix supports complex life and shields us from solar radiation via the ozone layer.
🧲
Powerful Magnetic Field
Generated by Earth's molten iron outer core, the magnetosphere deflects harmful solar wind particles, creating the auroras at the poles.
🌋
Tectonically Active
Earth's crust is divided into ~15 tectonic plates that slowly drift, forming mountains, oceans, volcanoes and causing earthquakes.
⏱️
Not Quite Round
Earth bulges at the equator due to its rotation — its equatorial diameter (12,756 km) is 43 km wider than its polar diameter.
🔥
Incredibly Hot Core
Earth's inner core reaches ~5,400°C — about as hot as the surface of the Sun! It's solid iron due to immense pressure despite the heat.
Earth's Interior Structure
Inner Core
Solid iron-nickel · ~5,400°C · 1,220 km radius
Outer Core
Liquid iron-nickel · 4,000–5,400°C · Generates magnetic field
Mantle
Semi-solid silicate rock · 2,900 km thick · Drives tectonics
Crust
5–70 km thick · Oceanic & continental · Where life lives
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