Earth (planet)

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The Earth is the third planet from the Sun in the Solar System.  As a planet, it took a while before it was even realised it was even a planet or it's relationship to the solar system. For the humans on it it took quite some clever thinking to realise where it was.

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View of the Earth from the International Space Station. Hurricane Ike. image: NASA


Orbit basics:

  • Distance from sun: between 147,098,291 and 152,098,233  km (the average is called 1 AU (astronomical unit)
  • Orbital period (it's year):  365.26 Earth days
  • Moons (natural satellite):


Planet basics:

  • Type of planet: The original rocky/terrestrial
  • Length of day: 23.934 hours
  • Average radius: 6,371.00 km
  • Mass: 5.9722 x 1024 kg
  • Surface gravity: 1 g or 9.80665 m/s2
  • Mean density: 5.515 g/cm3
  • Surface temperature: min of−89.2 °C average of 14 °C maximum of 57.8 °C
  • Atmosphere: Substantial enough
  • Pressure: 1 bar or 101.325 kPa (Mean Sea Level)
  • Atmospheric composition: 
    • 78.08% nitrogen (N2) (dry air)
    • 20.95% oxygen (O2)
    • 0.93% argon
    • 0.038% carbon dioxide
    • About 1% water vapor (varies with climate)
    • wide range other chemical traces, such as NOx(nitrous oxides), SO (sulphur oxides), O3 ozone (safer and essential in the ozone layer, but a health hazard at lower altitudes)