NASA / ADBOE STOCK / RYAN WILLS
Our universe is developing, so it must have been smaller in the past. Indeed, if we rewind our cosmological film, we see the universe shrink almost at a point – the big bang – about 13 billion years ago. When when did the time started? Alas, things are not so simple. The general theory of relativity of Albert Einstein tells us that the backdrop of the universe is a fluid continuum, space-time, in which neither space nor time have absolute meaning. In addition, in Big Bang, space-time deforms at a point of infinite density called singularity. We cannot say that this is where time begins, only that it marks a break beyond which we cannot extrapolate.
Despite this, some cosmologists believe that there was a “before” the Big Bang. Some suggest that another universe preceded ours and that it has contracted and then “Abundance” At the Big Bang, causing the expansion era that we observe now. More radically, cosmologist Roger Penrose proposed that new universes can emerge from those who do not contract, thanks to a spectacular “replay” of all space-time.
In these two scenarios, time is eternal, but it is only a possibility. Cosmologists Stephen Hawking and James Hartle suggested that time was once an ordinary dimension like space, which derailed the Big Bang in space-time. Another bizarre idea is that space-time is made of particle pieces. If this is the case, these could be arranged in different phases, similar to steam and liquid water. Maybe the Big Bang was the point to which they “condensed” in the fluidThe continuous space-time that we observe today. …
