Is there more than universe?

It is not a useful exercise to ask questions whose potential answers cannot be verified experimentally.

The extent of space and time is fully contained within an N-dimensional (N = 11?) universe described by general relativity, quantum mechanics, and is consistent with a big bang at t=0.

People just can't seem to get past the assumption that this N-dimensional universe sits within some M-dimensional (M > N) "hyperspace" in which other N-dimensional universes might exist. There is no need for this complexity. It's totally fabricated from our obsession with curved space having to reside within some Euclidian space having a higher dimensionality. But again, that's a totally unnecessary crutch.

There is only one Universe. Big Bang is just a Theory. One Theory says the Big Bang was NOT the creation of the Universe just an event that repeats itself.

Depends on your definition of universe. The classical definition of the universe means everything therefore by definition there can't be more than one universe.

There are some branches of cosmology that believe our universe is just one universe in a multiverse of course that requires a different definition of the word universe.

It is widely believed amongst cosmologists that there is an observable horizon to the universe that is to say there is more to the universe than can be seen with the even the biggest telescope imaginable.

Unverse is infinite. First we believed that sun is the big mass. But later it was proved that there is an existence of many massive structures than the size of sun. First we thought of our milkyway galaxy constitute the universe. Later we found about andromeda galaxy. Its not easy to predict thae size of universe. George gamov , one who said about big bang thoery told that primary nebula was shattered into many peices by the process called second separation to form heavenly bodies like planets and stars. The size of universe is unimaginable. Yep there may be something which is more than universe.

yes. our ability too understand what exists, and how to use that understanding to improve our way of life. so, get to school, and learn what is out there, so you can understand why things are the way they are. and how we got to where we are today, and where we would like to go tomorrow.