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Earth mass (M⊕, where ⊕ is the symbol for planet Earth) is the unit of mass equal to that of Earth. 1 M⊕ = 19±0.0006)×1024 kg . (5.972 Earth mass is often used to represent masses of rocky terrestrial planets.
One Earth mass can be converted to related units:
- 568±0.000003 81.300lunar mass (ML)
- 9.35 Mars mass (Mars has 0.107 M⊕)
- 0.0583 Neptune mass (Neptune has 17.147 M⊕)
- 0.0105 Saturn mass (Saturn has 95.16 M⊕)
- 0.00315 Jupiter mass (MJ) (Jupiter has 317.83 M⊕)
- 0.000 003 003 solar mass (M☉) (The Sun has 332946 M⊕)
History of measurement
The GM product is determined using laser ranging data from earth orbiting satellites.
using earth's gravity, g as the acceleration and combining the equations gives
Solving for M⊕ gives the relationship
With this method, the values for Earth's surface gravity, radius, and G were measured empirically.
Even earlier attempts[when?] to "weigh" the earth involved estimating the mean density of the earth and its volume.
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Earth's mass is constantly changing due to many contributors. Currently, the mechanisms responsible for the loss of mass exceed the mechanisms associated with mass gain. A number of factors are involved, but can be classified into two categories; net transfer of matter, and mass which is gained or lost through the absorption or release of energy due to the Mass–energy equivalence principle. Several examples are provided:
- "Solar System Exploration: Earth: Facts & Figures". NASA. 13 Dec 2012. Retrieved 2012-01-22.
- The Astronomical Almanac for the Year 2014. St. Lois, MO 63197: U.S. Government Printing Office. 2014. p. K7. ISBN 978-0-7077-41420. Retrieved 5 February 2016.
- "Solar System Exploration: Neptune: Facts & Figures". NASA. 5 Jan 2009. Retrieved 2009-09-20.
- "Solar System Exploration: Saturn: Facts & Figures". NASA. 28 Jul 2009. Retrieved 2009-09-20.
- Williams, Dr. David R. (2 November 2007). "Jupiter Fact Sheet". NASA. Retrieved 2009-07-16.
- Ries, J.C.; Eanes, R.J.; Shum, C.K.; Watkins, M.M. (20 March 1992). "Progress in the determination of the gravitational coefficient of the Earth". Geophysical Research Letters 19 (6). doi:10.1029/92GL00259. Retrieved 5 February 2016.
- "Spacecraft Measurements of the Cosmic Dust Flux", Herbert A. Zook. doi:10.1007/978-1-4419-8694-8_5
- Carter, Lynn. "How many meteorites hit Earth each year?". Ask an Astronomer. The Curious Team, Cornell University. Retrieved 6 February 2016.
- Sulzman, F.M.; Genin, A.M. (1994). Space, Biology, and Medicine, vol. II: Life Support and Habitability. American Institute of Aeronautics and Astronautics