oc Your late friend Wolter would like to theorize that there is Planck
gravity,and its the source of all gravity created forces(the other 3)
and is bring its force home we see and measure this push as gravity
holding stuff in place(inertia) and pushing stuff together as
gravitation. That give the reason why inertia,and gravity are two sides
to the same coin. Maybe not exactly right,but nothing is exact. bert