If the centrifugal force of planetary movements did not precisely balance the gravitational forces, nothing could be held in orbit around the sun. Think of a whirlpool effect versus a turntable effect - planets would either fall into the Sun or be cast out of orbit.
Planetary Placement:
If Jupiter were not in its current orbit, we would be bombarded with space material. Jupiter's gravitational field acts as a cosmic vacuum cleaner, attracting asteroids and comets that would otherwise strike earth.
Gravitational Interaction with the Moon/Moon's Distance from Earth:
If Greater?
-
Tidal effects on the oceans, atmosphere, and rotational period would be too severe for life to exist
If Less?
- Earth's orbital obliquity would change too much causing climatic instability
Axial Tilt of 23.5 degrees (not accounting for a possible water canopy atmosphere) - such as what Genesis calls "the firmament"?
Any change would cause surface temperatures differences to be too extreme to support life.