China unveils world’s first timekeeping software for the moon, where clocks ticks faster

Chinese researchers have released the world’s first software for lunar timekeeping, a tool designed to support precise navigation and landings as a new global race to the moon gathers pace.

Clocks tick faster on the moon than on Earth due to weaker gravity – by about 56 millionths of a second per day. The effect, predicted by Albert Einstein’s theory of general relativity, is tiny but accumulates over time, making Earth time increasingly unreliable for lunar operations.

To address this, a team from the Purple Mountain Observatory in Nanjing built a model that accounts for both the moon’s weaker gravity and its motion through space, allowing events on the moon to be accurately synchronised with clocks used on Earth.

The researchers reported that their method remained accurate to within a few tens of nanoseconds even over 1,000 years, according to a paper published in the December issue of Astronomy and Astrophysics.

They also packaged the model into ready-to-use software, enabling users to compare lunar and Earth time in a single step instead of relying on complex calculations. The team said the goal was to make lunar timekeeping practical as missions to the moon become more frequent.

Jonathan McDowell, a Harvard astronomer and space historian, said lunar timekeeping was becoming a real engineering need rather than something that could be handled on a case-by-case basis using Earth time, as in the past.

Differences as small as a microsecond could quickly become significant in navigation systems, affecting calculations over timescales of a minute, he said.

South China Morning Post