The Big Bang and the original size of Universe

[Martyn Arthur]

TL;DR

If the Universe occurred and expanded (plum pudding model say) how much 'space' did it occupy at the outset?

I am trying to understand / visualise, recognising that the Big Bang is not thought of as an explosion, how the Universe could have come into existence as a 'point' but came into existence 'everywhere'?
Is it a concept that such a point was then everywhere, and that the mass of the Universe, as is now, was coalesced into that point?
I am just in my first year of the physics degree and my maths does not extend to any great degree, but is it the case that the maths quantifies an opening situation?
Martyn

 

[PeroK]

The big bang model does not extend all the way back to the universe as a single point. In fact, such a singularity is really a sign that we need a new model to study the universe when it becomes sufficiently dense.

If you are a physics student, you could try:

https://www.wiley.com/en-gb/An+Introduction+to+Modern+Cosmology,+3rd+Edition-p-9781118502143

Although, you might want to concentrate on your course syllabus.