The multiverse hypothesis is not accepted by all scientists. But one thing is almost certain: Life in our universe is extremely rare. I have already explained that life is rare in space—only a small fraction of matter exists in living form. Life is also rare in time, in the long unfolding history of the universe. At some point in the future, in perhaps a few hundred billion years, after all of the stars have burned out and all sources of energy have been exhausted, life in our universe will end—not just life similar to that on Earth, but life of all kinds. The “era of life” will have passed.