system
Given the following post, respond as if you're commenting on Reddit:
human
How are we able to calculate the mass of the Sun? 

I understand that you use The Law of Universal Gravitation, but can someone give me an in-depth explanation?
gpt
Law of Universal Gravitation
F = G*M1*M2/r^2
We know G, we know M2 (mass of earth), and we know r (earth-sun distance), so all we need to do is calculate F.
We also know that for circular motion
F = V^2/r
r is the same as above, and V (velocity of earth) we can calculate based on the period of revolution (1 year) and the distance (2*pi*r).

Of course the orbit is slightly elliptical so you can get a bit more technical, but that should get you most of the way there.