The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein’s theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.
This would be quite interesting if validated. The furthest Hubble can see is about 10-15 billion light years. It seems that if the universe has always existed, then the best evidence would something older than 13.8 billion years old.