system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: They say the big bang started it all. How was the stuff that started it there in the first place..?
gpt
We don't know, but one of the easiest to comprehend theories is that the universe we are currently in is just one in a long series of expansion/contraction cycles. In this theory, eventually the universe will stop expanding, and start collapsing, all the way back into the singularity which the big bang started from again, to be a singularity for an indeterminate and irrelevant amount of time, before another big bang occurs. Of course that doesn't solve the original problem of where it came from, kinda chicken and egg there. 

Our minds have a problem comprehending how something could just "be", without something originally creating it or putting it there. That doesn't mean it isn't possible though. The Singularity could "just be". It could be the ultimate "omega point" of time and space together. An eternal egg. Where everything comes from, and where everything returns to.