Earth
- Diameter and circumference of the earth:
- Equatoral diameter is 7,927 miles (12,757 km)
- Polar diameter is 7,899.83 miles.
- Equatorial circumference is 24,902 miles (40,075 km).
- Polar circumference is 24,860 miles (40,008 km).
- Average distance is 92,900,000 miles (149.6 million km) from the sun --
- Perihelion is at 91,500,000 miles (147,100,000 km).
- Aphelion is at 94,500,000 miles (152,100,000 km).
- Average surface temperature (variable with climate) is 58°F (14°C).
- The Earth has one moon.
- Rotation takes 23 hours 56 minutes.
- Revolution takes 365.26 days.
- Axial inclination is 23.5°.
- Earth's density is 5.522 times that of water:
- The density of water is 1 at 4°C.
- Equivalent to 344.7 pounds per cubic foot.
- The Earth is the densest of all Solar System planets.
- Earth's central core is comprised of a heavy nickel an iron mixture with a relative density of 13 times that of water.
- The weight of the earth is estimated to be 6.586 x 10^21 tons.
- OR 6,586 billion billion tons...
- OR 6586 followed by 18 zeros!!!
- Composition and structure of the Earth:
- The Earth is comprised of a core of nickel and iron, a mantle of molten material, and a crust of lighter, silicate-based material.
- Diameter of the solid inner core is 1,390 miles (2,400 km).
- The temperature at the Earth's core is 6,690°F (3,700°C), though melting of the nickel and iron core is not possibly due to immense pressure.
- The outer core of molten iron and nickel, with smaller amounts of silicon, is 1,400 miles (2,250 km) thick.
- The 1,800 mile- (2,900 km-) thick mantle is comprised of a mixture of molten rock which moves in convection cells as it heats and cools.
- The top layer, or crust, varies in thickness form about 3.75 miles (6 km) thick beneath the ovean floors, to about 40 miles thick in mountainous areas of continental crust.
- Sections of crust above the mantle's convection cells, or tectonic plates, push against one another or separate from each other, causing earthquakes and volcanic eruptions.
- The action of Earth's rotation on the solid metal core and surrounding molten mantle create electromagnetic currents within the Earth.
- These electromagnetic currents form a magnetic field around the Earth in a North-South plane.
- The third planet from the Sun, Earth is the 5th largest and the 5th smallest in terms of volume.
- Earth's atmosphere:
- It is comprised of 78.08% nitrogen, 2094% oxygen, 0.93% argon, varying amounts of water vapor, and other gases.
- Sufficient amounts of water exist in the atmosphere to cover the entire surface of the planet 1 inch (2.5 cm) deep.
- Earth's ionosphere is approximately 100 miles (160 km) above the plaent's surface, reflecting some radio wave transmissions and allowing others to pass.
- The troposphere is the lowest layer of atmosphere where weather and wind occur.
- The troposphere is about 10 miles (16 km) thick at the equator, but only about 5 miles (8 km) deep at the poles.
- Tropics, with their vast rain forests, drive the weather systems feeding the Earth with 368,000 cubic miles (450,000 km3) of water drawn up as vapor from the oceans annually.
- Without this vital water vapor, rain and snow could not precipitate in the higher latitudes and the life cycle on Earth would eventually disappear.
- The only planet in the Solar System capable of life, Earth is also the only highly-colored object in the sky with its blue oceans and white clouds.
- A geologically active planet, Earth has more than 500 active volcanoes today, about 80 of which are beneath the surface of Earth's oceans.
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