It violates the first law of thermodynamics, which says you can’t create or destroy matter or energy. Critics claim that the big bang theory suggests the universe began out of nothing. Proponents of the big bang theory say that such criticism is unwarranted for two reasons.
The first is that the big bang doesn’t address the creation of the universe, but rather the evolution of it. The other reason is that since the laws of science break down as you approach the creation of the universe, there’s no reason to believe the first law of thermodynamics would apply.
Some critics say that the formation of stars and galaxies violates the law of entropy, which suggests systems of change become less organized over time. But if you view the early universe as completely homogeneous and isotropic, then the current universe shows signs of obeying the law of entropy.
Some astrophysicists and cosmologists argue that scientists have misinterpreted evidence like the redshift of celestial bodies and the cosmic microwave background radiation. Some cite the absence of exotic cosmic bodies that should have been the product of the big bang according to the theory.
The early inflationary period of the big bang appears to violate the rule that nothing can travel faster than the speed of light. Proponents have a few different responses to this criticism. One is that at the start of the big bang, the theory of relativity didn’t apply. As a result, there was no issue with traveling faster than the speed of light. Another related response is that space itself can expand faster than the speed of light, as space falls outside the domain of the theory of gravity.
There are several alternative models that attempt to explain the development of the universe, though none of them have as wide an acceptance as the big bang theory:
The steady-state model of the universe suggests the universe always had and will always have the same density. The theory reconciles the apparent evidence that the universe is expanding by suggesting that the universe generates matter at a rate proportionate to the universe’s rate of expansion.
The Ekpyrotic model suggests our universe is the result of a collision of two three-dimensional worlds on a hidden fourth dimension. It doesn’t conflict with the big bang theory completely, as after a certain amount of time it aligns with the events described in the big bang theory.
The big bounce theory suggests our universe is one of a series of universes that first expand, then contract again. The cycle repeats after several billion years.
Plasma cosmology attempts to describe the universe in terms of the electrodynamic properties of the universe. Plasma is an ionized gas, which means it’s a gas with free roaming electrons that can conduct electricity.
There are several other models as well. Could one of these theories (or other ones we haven’t even thought of) one day replace the big bang theory as the accepted model of the universe? It’s quite possible. As time passes and our capability to study the universe increases, we’ll be able to make more accurate models of how the universe developed.
https://science.howstuffworks.com/dictionary/astronomy-terms/big-bang-theory7.htm
The inflationary epoch lasted from 10−36 seconds after the conjectured Big Bang singularity to sometime between 10−33 and 10−32 seconds after the singularity.
Following the inflationary period, the universe continues to expand, but at a less rapid rate.[1]
Inflation theory was first developed in 1979 by theoretical physicist Alan Guth at Cornell University.
It was developed further in the early 1980s. It explains the origin of the large-scale structure of the cosmos.
Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the Universe (see galaxy formation and evolution and structure formation).[2]
Many physicists also believe that inflation explains why the universe appears to be the same in all directions (isotropic), why the cosmic microwave background radiation is distributed evenly, why the universe is flat, and why no magnetic monopoles have been observed.
The detailed particle physics mechanism responsible for inflation is unknown.
The basic inflationary paradigm is accepted by most physicists, as a number of inflation model predictions have been confirmed by observation;[3] however, a substantial minority of scientists dissent from this position.[4][5][6]
The hypothetical field thought to be responsible for inflation is called the inflation.[7]
In 2002, three of the original architects of the theory were recognized for their major contributions; physicists Alan Guth of M.I.T., Andrei Linde of Stanford, and Paul Steinhardt of Princeton shared the prestigious Dirac Prize "for development of the concept of inflation in cosmology".[8]
In 2012, Alan Guth and Andrei Linde were awarded the Breakthrough Prize in Fundamental Physics for their invention and development of inflationary cosmology.[9]
“The other reason is that since the laws of science break down as you approach the creation of the universe, there’s no reason to believe the first law of thermodynamics would apply.”
This also means there is no reason to believe any of their models of what might happen would apply either. You simply cannot extrapolate if you can’t assume that the conditions you are extrapolating based on will remain consistent with what you can observe or infer from experiment. Once you assume those conditions change, if you continue to extrapolate you are just fudging the model to insert whatever conditions produce the results you desire.
“Some critics say that the formation of stars and galaxies violates the law of entropy, which suggests systems of change become less organized over time. But if you view the early universe as completely homogeneous and isotropic, then the current universe shows signs of obeying the law of entropy.”
The law of entropy doesn’t really say that systems become less organized, that is just a consequence. The law actually says that the system will tend to become more homogeneous, with every point in the system tending towards the same, lowest possible energy level. If the system was already completely homogeneous to begin with, then it would require an input of energy from outside the system to change that. However, the Big Bang theory treats the universe as a closed system, with no possible outside input. So there is definitely a contradiction there. Either it can’t start out homogeneous, or it can’t be a closed system. You can’t have it both ways.
“Another related response is that space itself can expand faster than the speed of light, as space falls outside the domain of the theory of gravity.”
Well, if we are talking relativity, space is integral to the theory of gravity, since it is distortion of space itself that produces the phenomenon of gravity. However, according to relativity, space must be able to transmit gravity instantaneously, so space being able to expand faster than the speed of light should not be a contradiction.