The emergence and early evolution of life may have been fundamentally shaped by the synchronization of environmental rhythms. Here, we propose the Tidal- Thermal Synchronization Theory (TTST), which posits that life's basic physio- logical systems emerged through the coupling of high-frequency thermal rhythms from hydrothermal vents with periodic tidal forces from the early Moon. This dual rhythmic system, combined with the solar day-night cycle, created a hierarchical temporal framework that guided the evolution of biological timing mechanisms. We present mathematical models describing this multi-scale environmental forc- ing and demonstrate how these rhythms could have provided templates for the development of fundamental biological systems including circulation and neural os- cillations. The theory o ers new perspectives on the Snowball Earth events and the subsequent Cambrian explosion, suggesting that disruption and restoration of rhythmic coupling may drive major evolutionary transitions. TTST provides a unifying framework for understanding how life internalized cosmic rhythms into its fundamental architecture.