Say what you will about the Big Bang balderdash, but one must admit that it prompts an immense number of questions and, of course, engenders a great deal of existential anxiety.   (How could the notion of us being part of something that popped out of nothing not induce a little bit of angst?)   One of the more common questions pertains to the "center" of the Universe: where it all started.     The problem many encounter when contemplating the Big Bang is its origin point.   Where in the Universe did the explosion occur and how far is our solar system from this cosmic ground zero?   Such a question seems logical, but is actually unanswerable and therefore problematic.  It is not merely that the question extends beyond our scope and eventually some clever descendant will discover an answer.      Instead, the question, itself, is predicated on a misconception: that the Big Bang is analagous to a conventional explosion happening at a discrete spatial point and expanding radially away from it.  That one should envisage the Big Bang this way is understandable, since we constantly refer to it as the most powerful explosion ever.    Consider that description poetic license if not accurate science.

Big Bang science, properly called "cosmology," begins with sheer ignorance.    Scientists don't know what transpired at the precise "birth" moment because the models tell us the Universe was born from a singularity: a mathematical point of no dimension.       Though quite powerful, theoretical physics is confounded by singularities, just as mathematics goes off the rails when someone tries to divide by zero.    Our inability to understand the conditions within a single point -since the term "within a singularity" is meaningless- precludes us from knowing what happened at time zero.      Physical models begin at something called the "Planck Wall," which is 0.000000000000000000000000000000000000000001 second after the Big Bang event.     This time span is the ultimate eye blink, but is not the same as the initial moment.

Though cosmologists are still ironing out the details, the Big Bang theory tells us that the Universe has expanded since formation and is currently expanding.    The initial theory assumed the Universal expansion would decelerate with time as the matter exerted a gravitational retarding force on it.    Within the last fifteen years, however, astronomers have discovered that the Universal expansion is accelerating!   As they have not yet identified the force responsible for this propulsion, they've ascribed it to 'dark energy,' a mysterious impulse that likely pervades the Universe, but eludes detection.    We know of it only because of its effect on what we can observe: the receding galaxies.

It is possible that the cosmos will expand forever; that ours is an eternal Universe destined to become increasingly more rarefied as the matter within it disperses.   Until we learn more about dark energy, any presumption about our Universe's fate will be speculative.   What we do know (or believe we know) is that we were all born out of nothingness.   Time, space, matter and energy all took form once the Big Bang singularity unfurled the Universe we inhabit today.  

All things: the galaxies within the Hercules supercluster; all the planets within all the galaxies; the Moon; Earth and all the material within it and around it; and every little speck within every little nook were once confined within a negligibly  small volume that ballooned out into the Universe.        There is neither middle nor edge anymore than there is before or after or outside.       Our space-time system is self contained* and any such spatially or temporally relative terms are sensible only when applied to regions within the Universe.  

We cannot define the starting point because it is everywhere.   You are in the middle of the Universe.  Then again, so, too are the phosphorescent ferns tucked away on a planet in the Horologium Supercluster.

*Of course, ours might be just one Universe of many. The notion of multiple Universes, once the sole reserve of science fiction writers, is physically feasible, although we're damned if we know how to prove the existence of other such universes.  They are theoretical constructs; but, then again, from the perspective of beings in an alternate Universe, so are we.     The more one tries to explain the nature, the stranger it becomes.