Earth mass
As Earth's mass (abbreviated M ⊕ , sometimes M E ) is defined as the mass of our planet Earth . The earth's mass is an astronomical unit of measurement and is about 5.9722 · 10 24 kg (5.9722 trillion tons). 67 percent of this is due to the earth's mantle , 32 percent to the earth's core and almost half a percent to the earth's crust . The masses of the oceans and the atmosphere are part of the earth's mass.
The earth's mass is often used as a reference to indicate the mass of other celestial bodies. In addition to astronomy, it also plays a major role in geodesy , physics and space travel .
Since the density of the earth by layering toward the center of the earth rises , which is moment of inertia of the earth is less than that of a homogeneous same solid sphere size and mass.
| Reference object | Mass [kg] | Mass [ M ⊕ ] |
|---|---|---|
| moon | 7.349 · 10 22 | 0.0123 (≈ 1 ⁄ 81 ) |
| Mars | 6.419 · 10 23 | 0.107 (≈ 1 ⁄ 9 ) |
| earth | 5.9723 · 10 24 | 1 |
| Jupiter | 1.8986 · 10 27 | 318 |
| Sun | 1.9884 · 10 30 | 333,000 |
determination
Since there are no classical scales for the earth, one has to analyze the effects of its gravitational field GM ⊕ . This can be determined very precisely by observing the orbit of earth satellites as GM ⊕ = 3.986004418 (8) · 10 14 m 3 / s 2 . To calculate the mass M ⊕ (in kilograms), however, one must know the gravitational constant G. At 6.674 30 (15) · 10 −11 m 3 / (kg · s 2 ), however, this is only relatively imprecisely known.
This had Henry Cavendish 1798 a Cavendish experiment determined for the first time, from which one mass and density of the earth (and other celestial bodies) could be calculated. Cavendish determined G with an accuracy of just under 1 percent, but today, with an estimated inaccuracy of 0.002 2 percent, one is only a good 2½ orders of magnitude better.
This leads to the situation that we know the mass relationships between celestial bodies far more precisely than the masses themselves. So we know the ratio of solar mass to earth mass with M ☉ / M ⊕ = 332 946.048 7 (7) to about 10 places.
The earth's mass can be considered a constant , as its mass changes will take place over millennia far beyond the measurement limits of M ⊕ and GM ⊕ . The mass increases are mainly due to the 40,000 tonnes of meteorite dust that fall on the earth every year, as well as mass losses due to the escape of light gases (especially hydrogen ) from the high atmosphere into space .
See also
Individual evidence
- ↑ Earth: Facts & Figures @ solarsystem.nasa.gov / planets, accessed October 29, 2014.
- ↑ IERS Technical Note no.36 Chapter 1 (PDF file; 322 KB).
- ↑ The Cavendish Experiment (PDF; English).
- ↑ Emma Goldberg: How to Cool a Planet With Extraterrestrial Dust . In: The New York Times . September 18, 2019, ISSN 0362-4331 ( nytimes.com [accessed October 26, 2019]).