Traditionally, scientists believe that the universe is incredibly great. The most distant light that we can see is the cosmic microwave background, whose light has come to us for more than 13 billion years. This is the boundary of the observed universe. Although, at first glance, this may seem a gigantic space, many cosmologists are sure that the size of the universe is much larger, perhaps even endless.
However, the recently published article on the preliminary publication server arxiv claims the opposite – that the universe observed we mainly is everything that exists.
Why do scientists think that the universe is so great? Firstly, this is the distribution of galactic clusters. The observed universe is homogeneous and isotropic. Secondly, spatial time is flat. Based on our observations, this suggests that the Universe is at least 400 times more observed.
Further there is a fact that the space microwave background is almost perfectly black. This led astronomers to the assumption of early cosmic inflation expansion after the Big Bang. If this model is true, then the Universe exceeds the observed part by 10^26 times.
Nevertheless, the arguments in favor of the “small” universe are associated with the theory of strings. Stan theory is mainly mathematical methods that are sometimes difficult to associate with physical models due to the lack of observed data. But some models of strings theory are more promising, especially those that are compatible with quantum gravity.
In conclusion, scientists add that questions about the size of the universe and possible theories of its structure are still open. If in the near future it is possible to detect traces of early cosmic expansion through gravitational waves, this may become a key argument. If not, maybe it’s time to carefully study the models of string theory.