The question "why" does not apply to the universe. Language is a system of analogies and induction. You can ask "why did you ask that?" or "why does the apple fall to the ground?" even though people and apples are different, and the "why" is a subtly different kind of question for each of them. In language, we make the analogy unconsciously, and move on. But the universe is not a person or a rock, so perhaps it does not have a "why". Consider the question "what is a rock thinking?". We know that rocks don't think. Well, universes don't have a why. The rock is obvious, because we routinely encounter other things which do not think. However, we have become pretty clever at figuring out "why" for so many things that we forget that "why" might not be a (literally) universal thing. There may be no analogy which actually turns this sequence of words into a real question.
(read Wittgenstein for a deeper discussion of the limitations of language and the emptiness of some traditional philosophical questions).
No. The universe is everything that exists.
The universe is everything that exists. It contains everything.
No. The universe is everything that exists.
The universe is commonly defined as all the time, space, matter, and energy that exist. It does not make sense to ask how something exists outside of what exists. If something exists, it, the space it occupies, and the time it exists in are all a part of the universe by definition.
Yes. The universe is everything that exists.
Gravity is the force of attraction that exists between all objects in the universe.
The real answer is universe
Everything that exists.
Everything that exists.
Everything that exists is either called the Universe or the Cosmos.
No, the word "universe" is typically not capitalized unless it is at the beginning of a sentence or part of a proper noun (e.g., Marvel Universe).
most matter that exists in the universe is in the plasma state