M-THEORY - 3
The Ekpyrotic Cyclic Model, from the Greek "out of the fire", tries to describe the structure of our Universe according to the M-Theory.
In our cosmos, only four of the eleven dimensions have expanded at the expense of the others. It would be placed on a 3-brane very close to a parallel universe, the two of them are separated from the eleventh dimension and are both flat and four-dimensional. They collide about every trillion years generating the Big Splat, a phenomenon that we refer to as the Big Bang, and that, due to the collision between these two universes, releases a large amount of radiation equal to that present in the first instant of our Universe. Due to quantum fluctuations, however, some parts of the two universes would collide earlier than the others, forming an uneven amount of radiation that generates the non-heterogeneous mass distribution from which comes the creation of galaxies: clusters and super-clusters separated by immense empty spaces.
This type of multiverse would then consist of the following stages:
Endless duration of time (which therefore pre-exists the Universe) and universes
Clash between branes
Big Splat
Inflation
Formation of universes
New clash with the destruction of the previous universes and creation of new ones
Dark matter would then be nothing more than the force of gravity of the cosmos close to us, while dark energy is a repulsive energy that empties the branes from the universes produced on it, dispersing the matter, and arranging it to a new collision. Also, acting as a stabilizer, ensures that the two branes that contain the two universes do not stray too far after the collision. It is, therefore, a residue of the gravitational attraction of previous collisions, also present in the void but it does not auto-generate itself. It increases the acceleration when the branes, once the thrust of the collision is exhausted, come back closer. Destroying and regenerating universes for infinite times, a perfectly balanced universe, suitable to host life like ours, would finally appear.
3-dimensional parallel branes composed of 2-d branes, which contain the strings. On the branes, two universes, linked by a string: when the two branes collide, so the universes, and the Big Splat happens
Although apparently absurd, this hypothesis can be falsified: in fact, the oscillation of the inflaton that expanded the Universe, according to the standard theory in the first instants, should produce distortions in the spacetime perceptible through gravitational waves, while the Big Splat would not cause them. Data from 2014, however, seem to point towards the inflationary theory, but supporters of the Big Splat argue it does not contradict the Big Bang and inflation, but simply explains their origin: at the time, however, no gravitational wave had yet been observed. The first observation happened in 2015.
PIC CREDITS
D3-brane et D2-brane - Rogilbert