There are two theories as to what the universe was like some 3.5 billion years ago that I am somewhat willing to entertain as possibilities for what matter, anti-matter and black matter (if the latter two exist) were doing. One is the inflationary model. It basically states that there was a big bang, some no longer existing inflationary force caused the universe to expand from a singularity to millions of light years across but relatively extremely flat, in a few seconds. Since then anti-matter has been propelling the universe’s matter into nothingness until the universe is so big that it will essentially be totally empty and a fraction of a degree above absolute zero. The End. There is a second theory that the universe is cyclic, going through periods of expansion that last for around 11 billion years and then contraction for around the same amount of time. As the universe contracts, gravity and heat tears apart matter to sub-atomic particles or perhaps to strings. Then when the pressure is too much there is a big bang sized explosion that propels the universe back out. If the first is correct there is no explanation of what is before and this is the only portion of time that life can exist, so every moment should be savored. If the second is correct and I suspect it is at least closer to the truth then this or something very much like this has already happened.