Asking what came before the Big Bang may be a meaningless question, if time itself began with the universe. The measured part is solid enough: the universe is 13.8 billion years old, yet the edge of what we can observe lies some 46 billion light years away, because space kept expanding while that light was in transit. Push back to the very first instant and every equation we have breaks down, while eternal inflation, a cyclic bounce and the Hartle–Hawking quantum origin are models that no observation can currently tell apart.
Asking what came before the Big Bang may be a meaningless question, if time itself began with the universe. The measured part is solid enough: the universe is 13.8 billion years old, yet the edge of what we can observe lies some 46 billion light years away, because space kept expanding while that light was in transit. Push back to the very first instant and every equation we have breaks down, while eternal inflation, a cyclic bounce and the Hartle–Hawking quantum origin are models that no observation can currently tell apart.
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