MoonSync — Lunar Clock & Site Selector

Frequently Asked Questions

What is Lunar Coordinated Time (LTC)?

LTC is a proposed Moon-based time standard. Because lunar gravity is weaker (gravitational blueshift) and the Moon's orbital speed is lower (transverse Doppler redshift), Moon clocks run approximately +56.02 µs faster per Earth day than Earth clocks. MoonSync cumulates this offset from J2000.0 (Jan 1, 2000, 12:00 UTC) to display the total LTC lead over UTC at any moment.

Why is the lunar surface temperature so extreme?

The Moon has no atmosphere to distribute or retain heat. In direct sunlight, temperatures reach +127 °C (400 K) at the sub-solar point; on the nightside they fall to −173 °C (100 K) — a 300 °C swing driven purely by the presence or absence of solar radiation. MoonSync estimates temperature using the Stefan–Boltzmann model: T (K) = 400 · sin(altitude)^0.25.

What is a Permanent Shadow Region (PSR)?

PSRs are polar craters on the Moon that have never received direct sunlight, due to the Moon's low axial tilt (1.54°). Temperatures can fall to −230 °C — cold enough to preserve water ice for billions of years. NASA's LCROSS mission (2009) confirmed water ice at the lunar south pole. MoonSync classifies any polar site (|lat| ≥ 87°) with negative solar altitude as a PSR.

How accurate are MoonSync's calculations?

MoonSync uses simplified Keplerian orbital elements and geometric optics suitable for education and illustration — not for navigation. Earth–Moon distance accuracy is ±3,000 km; LTC offset uses NASA's 2023 value of +56.0205 µs/day; phase timing drifts ≈±30 min over a synodic month. For navigation-grade results, consult JPL Horizons or USNO data.