Posted: Mar 19, 2012 3:34 pm
questioner121 wrote:z8000783 wrote:Yes, you have said this many times over the last hundred or so pages but you never specify what the issue is. This could be seen as someone simply attempting to muddy the waters without much mud available.
If you feel the issue is a theological one then perhaps you should say so.
John
The issue is not theological but it did originate from there.
One thing that doesn't seem quite right is the gravity of the earth. If the gravity of the earth is zero at the centre of the earth and it gets weaker as you go below the surface of the earth, how did it come together and stay together given that it was rotating from the beginning and actually rotating faster?
Overall gravity at the centre of the Earth (the gravitational centre by the way) necessarily must be 0 because you'll have equal gravitational forces acting.
A simple way to see this is to have a piece of rope, have one person pull one end and another person pull another end; all with the same amount of force. No movement will occur. Add another rope and repeat, add infinite ropes and repeat and you'll have yourself a circle with a definite centre with abolutely no movement occuring.
Also, when you go under the Earths crust and start going to the centre of the Earth the amount of gravity experienced must necessarily be less than what it was at the crust given that, while the radius is decreasing the mass is decreasing also. You can see this even in simple Newtonian gravitational calculations. There is a slight problem of the Earths density not being consistent throughout however, so if we account for densities it may very well be that halfway to the crust there is still an overall gravitational pull is similar to the Crust (Say 75% of what it was probably higher) but once you reach the denser material it will drop off significantly. You also then have to account for the gravitational effects of the mass of Earth that is above you at to the sides of you which is beyond the scope of my physics courses I think. (Some physics and astronomy courses)
Now think about this relative to the formation of the Earth. It wouldn't have mattered if the overall gravitational force in the area that would once become the Earth was 0.00001% that of Earths current gravitational force so long as the gravitational centre points to that area matter will accrete (SP?) in that spot.
So if we think about the formation of a planet and we assume that in the general location of that planets formation area there is a consistent field of matter, so that's to say there is similar sized particles and similar spacing between the particles which are travelling at similar angular velocities. There is necessarily going to be (unless the field goes on forever...) a point in the field that all other gravitational vector sums point to. Doesn't matter how strong of a force that point itself has (if you don't include vector sums and just look at that individual point). If I'm wrong on any of this someone correct me.
