sen-no-sen wrote:The Big Bang was made of energy, at a theoretically zero volume and at an infinite temperature (I insist on the theoretically, because in reality there was certainly a limit).
We agree, but if there is a limit, what is behind it, that is the question, and it is this notion that makes you dizzy !!
sen-no-sen wrote:To be in the middle of something you need a preliminary space ... which did not exist!
This is the concern, how is it possible that nothing exists, and that suddenly everything starts to exist ...
sen-no-sen wrote:Well if at the start the universe was concentrated in an infinitely dense and hot point, why did it suddenly expand?
This is still unknown, why a volcano explodes?
Your comparison with the volcano does not seem great to me, if the volcano explodes, we know why, overpressure!
sen-no-sen wrote:You have to know what we are talking about, what is time?
Has time always existed?
Has time had acceleration or even deceleration phases?
The notion of beginning and end requires time, except if we admit that time appeared at a time 0, there can be no "before", unless invoked a pre-time, or an a-time , a kind of eternity that escapes all calculation.
In my opinion time has always existed since otherwise we would never have arrived there !! Because if there is no time, time has no reason to start at a specific time. It is almost as paradoxical and fascinating as the fact that infinity can exist.
sen-no-sen wrote:The fact that there was a universe in contraction does not invalidate the fact that our current universe is expanding.
Not having all the data, we do not know if this is possible or not.
In any case, I really think I read somewhere that against all odds the expansion of the universe was accelerating, how is this possible since it contradicts the very principle of gravity and mutual attraction of the masses?