There are various theories to explain the origin of the Universe. Notably among them are the standard Big Bang model, the Steady State theory, Oscillating models, Vacuum Fluctuations, Chaotic Inflationary model and Quantum Gravity model.
According to the modern observations, the Universe is expanding. As one reserves the expansion and extrapolates back in time, space-time curvature increases, ultimately becoming a singularity. This singularity implies an infinite curvature constituting an edge. According to Big Bang theory, the Universe came out of nothing, an ex nihilo creation.
The steady state theory tries to avoid singularity by proposing that Universe is in an isotropic cosmic expansion state and as the galaxies recede new matter forms in the interstices of space created by the galactic recession. Extrapolations do not give infinite density instead it remains constant. No observations support this theory.
The oscillating theory does not presume an isotropic and homogeneous Universe. According to this theory, gravitational pull may overcome the force of expansion of the Universe and the Universe may start contracting, a Big Crunch. The collapsing Universe might not coalesce at a point and the material contents of the Universe might pass each other by owing to non-isotropic and non-homogeneous property.
According to Vacuum Fluctuation model, the Universe is a primordial vacuum existing in a steady state. Throughout this vacuum subatomic fluctuations constantly occur and mini-Universes are born. It presumes an indefinite number of the Universes.
According to Chaotic Inflationary model, inflation never ends. Each inflating domain of the Universe after reaching a certain value gives rise to another domain, and so on.
According to Quantum Gravity model the Universe needs to be defined by a wave function. This model eliminates the singularity by transforming the conical hyper-surface of a classical space-time into a smooth curved surface of quantum-relativistic space-time.
The most of the Physics community believe in Big Bang theory or Quantum Gravity model whereby the need for a creator is eliminated. The important point is out of nothing. The law of the Universe should be to evolve; to evolve even before Big Bang. Why can’t the law of Universes be scale dependent and space-time dependent? Why should the laws of nature be universal? Why can’t they be co-ordinate dependent? Why should conservation of mass-energy be always followed?
It is possible that before the arrival of time, there was space. The mixing of space-time may be an approximation, a recent phenomenon in our galaxy or ultimately incorrect theory. The space just by its existence (since the Universe had to evolve) deformed. After a certain degree of distortions and deformations the mass start producing and this process was highly non-linear and cascading. The mass produced may be ‘cosmon’ or combinations of gluons and leptons or their constituents. These masses coalesce to form Big Bang or combinations of Big Bang initial masses. There should be only one Universe. The initial Big Bang was too big for its constituents and too complex. The time taken for initial inflation, from the size of atom to the size of the grapefruit was also significant. One can not measure the time of the initial Universe from present clocks.
Infinity should be considered as absurd and range of any interaction should not be considered infinite. The force of gravity may scale down to exact zero well before infinity and for this to happen, the partners of graviton; scalars, vectors need to be incorporated into.
The bottom line is that there can not be any entity called God. Hypothetically, if it is believed that there was one, the God should also follow laws; laws of Physics. There is only one law that is, the Universe evolves and it is finite. The only thing that might not have an end is the age of the Universe.