BING BANG
The universe in which we live is expanding. We know it because we are watching galaxies and groups of galaxies moving away from us in the universe. This expansion began as soon as the universe was formed, some 14 billion years ago, during a hot, dense phase called the Big Bang.
The universe has no center, because it has no edge. In a finite universe, the space is bent so that if you could travel billions of light years in a straight line, you would end up coming back to where you started. It is also possible that our universe is infinite. In both cases, groups of galaxies completely fill the universe and move away from each other in every respect, following the expansion of the universe
It is often said that the Big Bang was an explosion in an empty space, and that this explosion developed in this empty space. This is wrong.
The Big Bang has created space and time. At the beginning of the universe, space was completely filled with matter. The material was originally very hot and dense, then expanded and cooled to give the stars and galaxies we see today in the universe.
Although space may have been concentrated in a single point at the time of the Big Bang, it is also possible that it was infinite from its origin. In both scenarios, space was completely filled with matter at its beginning.
There is no center to this expansion, the space 'swells' just in every way. An observer in any galaxy sees most of the other galaxies in the universe moving away from him.
The only answer to the question "Where did the Big Bang take place" is that it has happened in every corner of the universe.
The Earth is not expanding, nor is the solar system any more than the Milky Way. These objects formed under the influence of gravitation and ceased to expand. Gravitation also holds galaxies together in groups and clusters. It is mainly the groups and clusters of galaxies that move away from each other in the universe.
The space was created by the Big Bang. Our universe has neither edge nor border - there is no 'outside' to our universe (see question 1). It is possible that our universe is only one of an infinity of universes (see question 4), but these universes do not necessarily need a 'space' to exist.
Time was created by the Big Bang - we do not know if it existed before the Big Bang. However, it is very difficult to answer such a question. Some theories suggest that our universe belongs to an infinity of universes (called a 'multiverse') in perpetual creation. This is possible, but extremely difficult to prove.
It is likely that our universe is infinite, and filled with matter everywhere since the Big Bang (see question 2). There is also serious evidence that in the early days of the universe, the universe experienced an expansion whose speed was much greater than that of light. It is possible to create such an expansion, in which the particles do not move at high speed, but where the space between the particles increases considerably.
We can imagine galaxies as balls placed on a rubber sheet that represents space. If we stretch the leaf, the balls move away from each other. Two balls close will only move slowly. Balls very far away will seem to run away at high speed. There is no limit to the expansion speed of the space.
Space is the geometry of our universe. Changes in the size or shape of space can occur because of movement of matter or energy in the universe, or because of changes in the content of the universe in terms of matter and energy.