Question

Generally describe what forces ultimately shaped the earth into its modern form

Answer 1

The force of gravity is a major force that created the earth.  As rocks and ice clumped together as they spun around the newly formed star (sun), the force of gravitational pull increased and attracted more debris (rocks and ice). The clumps of rocks, debris, and ice, therefore, grew into a planet.  

Another is electromagnetic force. The spinning currents in the outer core of the earth create a dynamo effect that forms a magnetic field around the earth. This shields the earth from the solar storms of the sun hence protects life and the atmosphere.

Weak nuclear force is responsible for maintaining the heat of the earth’s interior which is critical for maintaining the dynamo  effect of the outer core so the earth is protected by its magnetic field.