The Physics Factbook
Edited by Glenn Elert -- Written by his students
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|Cutnell, John D., & Johnson W. Kenneth. Physics- 3rd Edition.New York: Wiley, 1995: inside front cover.||"Sun, Mass, 1.99 × 1030kg"||1.99 × 1030 kg|
|"Solar System." Microsoft Encarta Encyclopedia. Microsoft Corporation, 1995.||"Although this nuclear fusion is destroying 600 million metric tons of hydrogen each second, the sun is so massive (2 × 1030 kg, 4.4x1030 lbs) that it can continue to shine at its present brightness for 6 billion years."||2 × 1030 kg|
|Davison, E. Soper. Mass of the Sun. University of Oregon.||"M ~ 2 × 1030kg."||2 × 1030 kg|
|Weast, Robert C. Handbook of Chemistry and Physics. Florida: CRC Press, 1980: F-178||"Mass (kg), 1.991 ± .002E30"||1.991 × 1030 kg|
|Hamilton, Calvin J. Sun. PlanetScapes.||"Mass in kg 1.989E+30"||1.989 × 1030 kg|
The sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass. To measure the mass of the sun we will use Newton's laws of motion together with his law of gravity. Those laws give a relation between the period (T) of a planet's orbit, the distance (a) from the planet to the sun, and a constant (G) measured in laboratory experiments. To measure the mass of the sun we will assume that the orbits are circles, and that the mass of a planet is tiny compared to the mass of the sun.
M = 4π2a3/GT2
Using this relation with T for the earth we get the mass of the sun. The period of the Earth is 31,536,000 seconds and the distance from the Earth to the sun is 1.496 × 1011 m.
M = 4(3.14)2(1.496 × 1011 m)3/((6.7 × 10-11N·m2/kg2)(365*24*60*60 s)2)
The mass of the sun is thus 1.99 × 1030 kg
Leon Vaysburd -- 2000
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