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   Earth mass
   Earth mass (M⊕) is the unit of mass equal to that of the Earth. 1 M⊕ = 5.9722 × 1024 kg. Earth mass is often used to describe masses of rocky terrestrial planets. The four terrestrial planets of the Solar System, Mercury, Venus, Earth, and Mars, have masses of 0.055, 0.815, 1.000, and 0.107 Ea...
   Found op http://en.wikipedia.org/wiki/Earth_mass
   
   

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