It was determined by RE'ers who used the following formulas:
F = G*((m1*m2)/r^2)
F = m2*g
Substituting one into the other gives us:
g=G*(m1/r^2)
Low and behold, it uses the earths radius.
nope. Other way around, you can measure gravity quite easily by looking at how fast things fall. Newtons law of spherical gravitation is what you use to calculate the radius of the earth from that number (it did not happen the other way around).
In what universe was Newton born before Erastosthenes?
In no universe.
Also, Newtons law of universal gravitation states the following F = G (m1/m2)/(r^2) in which r is not the radius but the distance between two point masses. How did you determine the radius of the earth with that formula? Also as you can see it uses G not g (Gravitational constant, not the earth's standard gravity), so either clarify what you meant or stop naysaying without arguments
G (m1/m2)/(r^2) is wrong.
I am not determining any 'radius' of anything with any formula.
You are being rather frustrating, for you do not elaborate on anything T_T.
I quoute: spherical gravitation is what you use to calculate the radius of the earth from
How is that not determining any 'radius'?
Also G*(m1/m2)/(r^2) is not "wrong", it is the formula that goes along with Newtons law of universal gravitation, the law you brought up to start with. So start clarifying and stop contradicting yourself.
It is simply the wrong equation...
The 4 most important progression of approximations for gravity are:
- (1) Uniform downward force field
- (2) Keplers law (predicts circular)
- (3) Newtons laws (predicts elliptical orbits)
- (4) Einsteins correction to newtons laws (which predicts and elliptical spirograph like orbit)
Now it happens that (1) is used in pretty much all physics on the earth but according to round earth theory (3) is more accurate (the difference is completely insignificant and just makes calculations harder)
Also you should study a bit more of the classical celestial mechanics before working on this stuff because I think you are stuggling with it a lot..
You realize you are saying that you are wrong? The eqaution is wrong as in "it isn't the eqaution you are supposed to use". This was what I was trying to point out, the fact still remains that you were the one who first started bringing it up (you mentioned Newtons law of universal gravitation, not me)
Newtons law of spherical gravitation is what you use to calculate the radius of the earth from that number (it did not happen the other way around).
You said that, not me. (and for someone who is telling me I need to learn "classical celestial mechanics" it is quite ironic that you provide the wrong name, it is universal, not spherical law of gravitation)
Now you say Newton's laws predict eliptical orbits, they don't, that goes under the Kepler's law part. So please get your facts right before trying to correct me. All you are doing is saying X isn't possible because of law Y Z and Q. "FET isn't possible because of Heisenberg's uncertainty principle!", nobody would buy that either. As to your little gibe at the end, all I would like to present you with is the following:
"Take the log out of your own eye, and then you will see clearly to take the speck out of your brother's" eye.
I am not saying I am right, but the way you are going about to try and disprove me is flawed and rude.