Quote from riffrafffpatrol:
A vehicle that doesn't require a stop loss? Do you seriously think that exists?
This is equivalent to someone saying-- "you've got to find those areas on earth that don't have gravity".... and then asking "can you be more specific on those exact locations?" LOL
The exact center of the Earth has zero gravity. Here is why.
The force of gravity on some test mass of mass m located at distance r from the center of the Earth is given by F = G M m/r^2
Here M is the total mass *inside* the sphere of radius r. So if we are at the surface of the Earth or higher up than M = M_Earth.
Let's call the mass inside of r, M(r). Let's reduce r. The total mass inside the sphere of radius r will reduce too. Assuming the Earth has uniform density d the mass M(r)=d * volume of sphere = d * (4pi/3) r^3.
So M(r) = constant *r^3 and F(r)= G M(r) m/r^2 = G constant *r^3/r^2.
Therefore F(r) is proportional to r, and will be zero in the center of the Earth.