Earth's Structure and Atmosphere

Earth's Key Characteristics

• Earth is the third planet from the Sun and the only known planet to support life.

Size and Structure

• Earth's diameter is approximately 12,742 kilometers (7,918 miles).
• The planet is composed of the crust, mantle, outer core, and inner core.

Atmosphere

• The atmosphere is made up of 78% nitrogen, 21% oxygen, and traces of argon, carbon dioxide, and other gases.
• The atmosphere supports life by providing oxygen, absorbing ultraviolet solar radiation, and reducing temperature extremes.

Hydrosphere

• 71% of Earth's surface is covered by water, primarily oceans.
• Water is essential for all known forms of life.

Biosphere

• The biosphere includes the regions of Earth where life exists, from deep ocean trenches to the upper atmosphere.
• It contains diverse ecosystems with millions of species.

Geological Activity

• Earth's surface features tectonic plates that move, causing earthquakes, volcanic activity, and mountain building.
• Continents drift due to plate tectonics.

Climate

• Earth's climate varies widely from polar ice caps to tropical rainforests.
• Latitude, altitude, and proximity to water bodies influence the climate.

Orbit and Rotation

• Earth orbits the Sun at an average distance of about 93 million miles (150 million kilometers).
• It takes 365.25 days to complete one orbit around the Sun.
• The planet rotates on its axis once every 24 hours, causing day and night.

Magnetic Field

• The magnetic field is generated by the movement of molten iron in the outer core.
• It protects the planet from harmful solar radiation.