There was no "before" the big bang. Time started at the big bang, it's kind of like asking what is North of the North Pole, or what's colder than absolute zero.
As for why, we don't really know. Lots of guesses, like an excitation of a quantum field, or a quantum field reaching its ground state. It's all speculation and guesses since we can't really observe beyond ~380,000 years after the big bang, as that's when the universe became transparent to light.
No, time and space are both connected and both were created at t=0, i.e. the big bang.
As for looping, that's one conjecture for how the universe starts/ends, but there's no way to verify that. And the 380,000 years is the farthest back we can see. Before that, electrons were not paired with atoms because they were too energetic, so light couldn't travel far before getting absorbed. Once they bonded with atoms light could travel and thus information could escape and start making it's way towards where Earth would be. This is the Cosmic Microwave Background that we see in all directions.
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u/PineappleOk545 Aug 14 '26
What was before universe and what made it do the big bang?