According to mainstream science, the universe began approximately 13.8 billion years ago, after expanding from a singularity in the Big Bang. Buddhism traditionally teaches that the universe is incalculably older than this, undergoing countless cycles of creation and dissolution.
While mainstream science can tell us the universe expanded from a singularity, where did that singularity come from, and what existed before it expanded? The Buddhist answer might be that there have been countless Big Bangs, followed by countless Big Crunches.
Buddhism also traditionally teaches about the existence of countless planets inhabited by intelligent life, with countless Buddhas from countless eons before the Big Bang. The idea that we’re alone in the universe is foreign to a traditional Buddhist perspective.