Closure

There was some confusion about my last post.

Some clarification is needed.

In thermodynamics, a "closed system" means energy can neither enter or leave. To talk about the universe as a "closed" thermodynamic system may not have any meaning, as nothing exists "outside" it, as there is no "outside".

In Cosmology, because of the expansion of the Universe, it has been speculated that the Universe falls into one of three categories: Open, Closed or Flat.

This is a gravitational consideration, and has nothing to do with thermodynamics.

The question involves the amount of matter in the Universe. Is gravity enough to stop the expansion? If it is, the expansion will stop, and a contraction will ensue, resulting in a "Big Crunch", or "GnabGib". This is a closed Universe.

As opposed to an Open Universe, in which the expansion continues forever.

AND a Flat Universe where gravity is just enough to halt the expansion only.

Trusting that Closure has been reached....