What is Earth

Earth is the third planet from the Sun in a solar system located in a galaxy called the Milky Way. It is the only planet known to support life — which is why it’s so crowded.

Basic Stats

Fact	Detail
Age	~4.5 billion years old
Diameter	~12,742 km (about 7,918 miles)
Surface	71% water, 29% land
Atmosphere	Mostly nitrogen (78%) and oxygen (21%)
Day length	24 hours (one rotation)
Year length	365.25 days (one orbit of the Sun)
Moons	1 (simply called “the Moon”)

The Surface

Earth’s land is divided into 7 large masses called continents:

Africa — the oldest inhabited continent, enormous diversity
Antarctica — frozen, almost no permanent human population
Asia — the largest continent, home to ~60% of all humans
Australia/Oceania — includes Australia, New Zealand, and Pacific islands
Europe — small but historically very influential
North America — includes the US, Canada, Mexico, and more
South America — includes Brazil, Argentina, Colombia, and more

These continents are surrounded by five oceans: the Pacific, Atlantic, Indian, Southern, and Arctic.

The Atmosphere

The thin layer of gas surrounding Earth is called the atmosphere. It does several vital things:

Provides oxygen for breathing
Blocks harmful radiation from the Sun
Traps warmth (the greenhouse effect) — life depends on this, though humans have been accidentally overdoing it lately (Climate & Environment)
Creates weather — rain, wind, snow, storms

Day and Night

Earth spins on its axis. The side facing the Sun experiences day (light, warm). The side facing away experiences night (dark, cooler). This 24-hour cycle governs when most humans sleep, work, and eat.

Seasons

Earth orbits the Sun on a tilted axis. This tilt causes seasons:

When your half of Earth tilts toward the Sun → Summer (warmer, longer days)
When your half tilts away → Winter (colder, shorter days)
In between → Spring and Fall (Autumn)

Seasons are opposite in the Northern and Southern Hemispheres.

Life on Earth

Earth is teeming with life — an estimated 8.7 million species of plants, animals, fungi, and microorganisms. Humans are just one of these. They have, however, had an outsized impact on nearly all the others.

🌍 Everything Chad will encounter — every human, building, tree, ocean, and cloud — exists on or above this one small rock.