Planets {Earth} can be third nearest to Sun.
properties
Diameter is 7917 miles, or 13,000,000 meters, at equator. Circumference is 24902 miles. Diameter at equator is 26.7 miles more than diameter through poles. Density is 5.5 g/cm^3, highest in solar system. Mass is 10^30 grams. Earth will last 10^16 seconds.
properties: orbit
Earth is 149,000,000,000 meters from Sun. One orbit takes 365 1/2 days in a sidereal year. Speed around Sun is 18 miles/second. In Northern Hemisphere, summer is seven days longer than winter, because Earth is closer to Sun then.
properties: rotation
Rotational speed at equator is 0.3 miles/second. Earth turns 15 degrees each hour, as it rotates every 24 hours west to east. Spin slows through tidal interaction with Moon and Sun. 4 x 10^9 years ago, day was 10 hours long. In Cambrian Era, day was 21 hours long. Axis tilts 23.5 degrees from orbit plane.
properties: temperature
Average surface temperature is 22 C. Heat is half from radioactive decay and half from kinetic energy gained from potential-energy loss as matter gathered by gravity at formation.
atmosphere
Air is 10^-6 of Earth weight. Average surface pressure is one atmosphere. Hydrogen-gas halo {geocorona} goes out to 15 radii, emitting ultraviolet light.
moon
Earth has one moon.
Physical Sciences>Astronomy>Solar System>Planet>Planets
5-Astronomy-Solar System-Planet-Planets
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Date Modified: 2022.0224