The visible universe, also known as the observable universe, refers to the portion of the universe that we can observe from Earth or any other vantage point within our cosmological horizon. It is limited by the distance that light has had the opportunity to travel since the Big Bang, given the age of the universe and the finite speed of light.
Estimates suggest that the visible universe has a radius of about 46.5 billion light-years. However, it is important to note that the universe is expanding, so the distance to objects at the edge of the observable universe is increasing over time.
As for the entire universe, its size is not definitively known. It could be infinite, or it could have a specific size beyond what we can observe. The visible universe is just a tiny fraction of the entire universe, and its actual size remains a topic of ongoing scientific research and investigation.
It's worth noting that the concept of size becomes challenging to grasp when discussing the universe, especially if it is infinite or exists in higher-dimensional space. Our understanding is limited by our current observational capabilities and the theories we have developed to explain the cosmos.