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planet · home planet

What is Earth?

Our home: the only planet known to have life, oceans of liquid water and moving tectonic plates.

Worth knowing about Earth

Sidereal rotation: 23.93 hours. Solar day (noon to noon, on average): exactly 24 hours by definition — what a clock actually measures.

Why it stands out
Stand on a beach, eyes about 1.25 m above the sea, and the horizon is roughly 4 km away; on a hilltop about 125 m above the land around it, roughly 40 km. That is an impression, not a measurement, and round on purpose: enough to show that the Earth is big, but not unimaginably big, and that it does not go on for ever. Light takes 1.282 seconds on average to reach the Moon — anything from about 1.2 to 1.35 seconds, because the Moon’s path is not a circle and its distance changes through the month — and 8 minutes 19 seconds to reach the Sun.
Its weather
A nitrogen-and-oxygen atmosphere, a water cycle and every kind of climate.
How far it is from the Sun
1 AU = 149,597,870.7 km, exact by definition since 2012.
How we know: For nearby planets, scientists bounce radar signals off them and time the echo (light-speed × time ÷ 2 = distance, because the signal goes there and back); Kepler’s laws then give every other planet’s distance, and Newton’s law of gravitation explains why. Masses are found by watching how strongly a planet’s gravity tugs on a moon, another planet, or a passing spacecraft. Rung 3 of the cosmic ladder — how the solar system is arranged
Earth — Rendered from a map, not photographed.
The numbers
Across12,742 km
Distance from the Sun, on average1 AU · 149.6 million km · sunlight takes 8 minutes 19 seconds
Once round its orbit365¼ days
Sunrise to sunrise24 hours
Temperature15 °C (from −89.2 to 56.7)
Also found therenitrogen, water, carbon dioxide, iron, rock, sulphur, tin, lead, methane

How anyone knows this

Games it appears in

Show Earth in the model🕒 When can I see Earth?☀️ Everything the Sun holds🌙 Plan an evening outside