Convert Hour (h) to Planck Time (tₚ) instantly.
About these units
Hour (h)
An hour, defined as 60 minutes or 3,600 seconds, is one of the most universally recognized time units. It emerged from ancient Egyptian timekeeping, where daylight was divided into 12 equal segments, a tradition that eventually influenced Greek and Roman clocks. The hour structures human activities: work schedules, travel planning, academic periods, medical dosing intervals, and astronomical observations. Its widespread adoption across cultures demonstrates the human tendency to organize life into consistent, predictable cycles. Even in scientific contexts where seconds dominate, the hour persists in fields like meteorology, orbital mechanics (e.g., solar time), and industrial processes. It bridges the gap between precise atomic time and everyday human experience.
Planck Time (tₚ)
Planck time is the smallest meaningful unit of time in known physics, defined as the time it takes light to travel one Planck length. It equals approximately 5.39 × 10⁻⁴⁴ seconds. Below the Planck time, current theories of spacetime—General Relativity and Quantum Mechanics—break down, and we enter a regime where quantum gravity dominates. Planck time defines the theoretical boundary of the earliest moments of the universe, immediately after the Big Bang, before classical spacetime emerged. It is not a unit we can measure directly; rather, it represents a fundamental limit set by nature's constants, including the speed of light, the gravitational constant, and Planck's constant. The Planck time is the frontier where physics transitions from the known into the speculative—where time itself may become granular, discontinuous, or fundamentally different from the human conception.