The non-observable universe, also known as the unobservable or unreachable universe, refers to regions of the universe that are beyond our current ability to observe due to the limitations imposed by the speed of light and the finite age of the universe. It is important to note that the non-observable universe is a theoretical concept and cannot be directly measured or observed.
The observable universe is the portion of the universe from which light has had enough time to reach us since the Big Bang, considering the finite speed of light. It is estimated to have a radius of approximately 46.5 billion light-years, which corresponds to a diameter of about 93 billion light-years.
However, the size of the non-observable universe is not precisely known. It is theorized to be much larger than the observable universe. According to the current understanding of cosmic inflation, a period of rapid expansion in the early universe, the universe could be significantly larger than what we can observe. Inflation suggests that regions of space that are currently beyond our observable horizon were once within it, but due to the expansion of space, they are now forever beyond our reach.
The exact size of the non-observable universe is uncertain and subject to ongoing research and theoretical investigations. It is a topic of active study in cosmology and theoretical physics, and scientists continue to refine our understanding of the universe's size, structure, and ultimate fate.