The cosmos and the big bang

Our expanding universe, that is, the world we can feel, develops as if it could be embedded in a larger space.

This larger space where our universe is contained exists is not only a mathematical trick used to have an image of the situation. In the simplest way of looking at it we can think in our universe as being a three dimensional sphere (not a three dimensional ball) which is expanding in a larger dimensional space. It is as a two dimensional sphere, a balloon, which lies in three dimensional space, which is expanding leaving the center, the big bang place, away from the universe at a given moment, which are the stars, etc. in the balloon.

The balloon began being a point in the larger space: the big bang. But then as it inflates, the big bang is left out of the balloon. Hence we can not point to the place of the big bang in our universe: the big bang lies in every direction.

We sense what our senses allow us to sense

Of course it is sort of difficult to conceive space and time without our senses. Space exists because there are bodies in it. Where come our senses from? Well, we are more or less convinced that it is through evolution: we don't thing microbes have senses that allow them to "feel" space and time. On the other hand may be there is much more in the universe that sounds, bodies, tastes, smells, colors and what we translate to our senses by means of the instruments we have invented: the full electromagnetic spectrum, the far away galaxies, some evidence of black holes, and so forth. Who tells us this is all the universe? Who tells us there are no other ways to sense or to conceive the universe?