JusticeMachine

May be a glaring over simplification but I will ask the questions:

Is inertia an infinite source or a finite one?
Is gravity an infinite source or a finite one?

I have heard of gravity's range described as infinite. If this is so and inertia is finite, then there will be a point in which gravity will overcome the inertia of the big bang and suck everything back in again. Then once it has all been pulled back in, it will reach critical mass again and explode outward again. This will go on and on but each time the explosive force will be weakened until, there will not be a big bang again.

Are there theories out there that follow there lines?

Philosoft

See: Dark energy.

Shadowy Man

You don't need to invoke cosmology to know that inertia can overcome gravity.

Gravity may be infinite in reach but it isn't infinite in strength.

You can launch a rocket off the earth at greater than escape velocity and it will never fall back down.

Same goes for the expansion of the universe, even without dark energy and accelerating expansion.

JusticeMachine

Never.....then that rocket will never succumb to the force of gravity, it's inertia is indefinite?

I know it may never come down in your life time, and it may not succumb to the earth's gravitational pull, but it will succumb, unless inertia is indefinite.

Shadowy Man

Why would it come back? Why does inertia have to be inifinite.

Try thinking of it in terms of energy rather than inertia.

A rocket on the Earth has a gravitational potential energy to overcome in order to leave Earth. If you give it kinetic energy that is greater than its potential energy it will leave and not come back, while still having a *finite* kinetic energy.

This effect is readily observed. For example, there are comets with hyperbolic orbits; they will leave the solar system and never come back.