We determine that the universe is finite and boundless based on the theory of relativity, but we can never pinpoint where the boundaries of the universe lie. Because our lives are constantly intertwined with the temporal boundaries of spacetime in the universe. Just like the longest chain of $BTC, we know the longest chain is finite and boundless, but we can never determine the longest chain that will be generated at any given moment. Because all the chains of time form the temporal dimension boundaries of the universe, and these boundaries are constantly being refreshed and regenerated. We are a part of this finite and boundless spacetime boundary.