The 18th century was the era of Newtonian mechanics' absolute time and space. The 19th century was the era of Maxwell's electromagnetic unification. The 20th century was the era of Einstein's geometric spacetime and quantum uncertainty coexisting. So, the 21st century is undoubtedly: Satoshi Nakamoto's new era of decentralized, irreversible time evolution. It holds the hope of achieving Einstein's dream of a unified theory, using the time chain to unify the major laws of physics.