Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: syhprum on 08/06/2010 20:46:03

Title: How did scientists calculate the mass of the Earth and Sun
Post by: syhprum on 08/06/2010 20:46:03

I could not resist this follow up from the previous question "How did scientists calculate the radius of the Earth and Sun"

Title: How did scientists calculate the mass of the Earth and Sun
Post by: Soul Surfer on 09/06/2010 08:44:16

A set of experiments was done on earth to measure the gravitational attractions between balls of various masses.  This defined the gravitational constant which was found to be the same fro an equal mass of any material.

The distances and orbital periods of the earth moon and sun have been known from earlier measurements and therefore using Newtons law of gravitation and the gravitational constant it is possible to calculate the masses of the earth moon and sun.

Title: How did scientists calculate the mass of the Earth and Sun
Post by: graham.d on 09/06/2010 10:23:50

If I have done the maths right:

Mass of the sun = ω²*r³/G

Where r is distance from sun to planet and ω is angular speed (= 2πf)