Convert Planck Time (tₚ) to Hour (Sidereal) (h (sidereal)) instantly.
About these units
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.
Hour (Sidereal) (h (sidereal))
A sidereal hour is 1/24 of a sidereal day, approximately 59 minutes and 50.17 seconds of solar time. Astronomers use sidereal hours to measure right ascension and to coordinate telescope pointing systems. Because stars return to the same apparent position after exactly one sidereal day, sidereal hours offer a stable celestial reference frame. While not used in daily life, sidereal hours are indispensable for precision observation of the universe.