Open Closed or Flat

To understand the creation of gravity, energy and mass (atom) you would have to have the understanding the process of the expansion and contraction of the universe. Currently there are three theories of how the universe is either open closed or flat based on the critical density of the universe. The critical density is the value or mass needed for the universe to collapse on itself.

If the average density of matter in the universe is greater than the critical density, the force of gravity will eventually rein in expansion and cause the universe to collapse upon itself (closed). Conversely, if the average density of matter in the universe is less than the critical density, gravity will lose its grip on matter and the universe will expand forever (open). If the average density of the universe is equal to the critical density--then the universe will expand to a maximum density and remain there for eternity (flat).

In simple terms, if the universe was open, it would be forever expanding and flat the universe will be in a perfect balance between the expansion and contraction. A closed universe means it will expands and collapse. Due to the calculations of the amount of matter in the universe, current theories point to the universe being open to be forever expanding because of mass of the universe is higher than the critical density.