To get an idea, for every grain of sand on Earth, there are a million stars or more. Our galaxy is just one among hundreds of billions of galaxies. Even so, all the matter in the cosmos is only an exceedingly small part of the universe. The Universe is, above all, an immense, almost empty space.
It is impossible to know the exact size of the Universe. It could even be infinite, although this does not seem likely. Since we do not know its shape, we cannot calculate its size either. Moreover, it is still expanding. We only know the size of the Universe visible from Earth.
Size Of The Visible Universe
The limit of the Universe visible from Earth is 46.5 billion light-years in all directions. That is a diameter of 93 billion light-years. One light-year is 5.88 trillion miles.
The calculation is enormous. Yet, it is only the part of the Universe that we can see. After the Big Bang, the Universe expanded so rapidly that some of its light has not yet reached us, and so we cannot see it.
But if the Universe is only 13.8 billion years old, how can there be objects farther away? Is it possible that they have moved away faster than the speed of light? The answer is the inflation of the Universe.
Inflation is the origin of everything: of space itself, time, and all known physical laws, including the limit of the speed of light. So, the inflation of the Universe is not subject to the limit of the speed of light. Inflation creates new space between objects and pushes them apart.