GalacticStorm
Smart Alec Know-It-All
Originally posted by yahman
How many types are there ?As far as I know there's the many worlds theory and the one associated with String Theory ? 🙂
Admittedly what little knowledge i have on the subject comes from online sources. Here are the others:
Open multiverse
Alexander Vilenkin with Jaume Garriga and others, have recently argued that there are an infinite number of regions of space the same size as our observable universe that is, that one can travel forever in any direction and always continue to reach new points. This assumption relies on the theory that at some stage in the past matter was distributed fairly evenly across space, and later condensed to form objects dense enough to become the source for a big bang. However, in this situation we would expect that rather than there being only a single big bang, matter would condense in a number of places separated by astronomical distances, forming a network or lattice of big bangs all exploding and then contracting like a network of beating hearts or the atoms in a crystal. Thus, rather than having a single big bang and a single universe, there would be a collection of universes, or a multiverse.
Bubble Theory
The formation of our universe from a "bubble" of a multiverse was proposed by Andre Linde. This Bubble universe theory fits well with the widely accepted theory of inflation. The bubble universe concept involves creation of universes from the quantum foam of a "parent universe." On very small scales, the foam is frothing due to energy fluctuations. These fluctuations may create tiny bubbles and wormholes. If the energy fluctuation is not very large, a tiny bubble universe may form, experience some expansion like an inflating balloon, and then contract and disappear from existence. However, if the energy fluctuation is greater than a particular critical value, a tiny bubble universe forms from the parent universe, experiences long-term expansion, and allows matter and large-scale galactic structures to form.
Big bounce
According to some quantum loop gravity theorists, the Big Bang was merely the beginning of a period of expansion that followed a period of contraction. In this oscillatory universe hypothesis, (originally attributable to John Wheeler,) the universe undergoes an infinite series of oscillations, each beginning with a big bang and ending with a big crunch. After the big bang, the universe expands for a while before the gravitational attraction of matter causes it to collapse back in and undergo a Big bounce. Although the model was abandoned for a time, the theory has been revived in brane cosmology as the cyclic model.