It’s been 50 years since humans walked on the surface of the moon — but our half-century of lunar longing is quickly coming to an end. Space agencies and private companies are preparing a deluge of missions to our celestial neighbor, with the ultimate goal of establishing a base camp on its surface. While scientists are trying to solve the myriad issues presented by living on the moon (food, water, and shelter being chief among them), there’s another not-insignificant question that needs answering: What time is it on the moon? Moon missions in the past have operated on their own various timescales in relation to Coordinated Universal Time (UTC), but the short answer is: We don’t really know, because we haven’t decided yet.
In November 2022, representatives of space agencies around the world gathered at a European Space Agency facility in the Netherlands to answer this very question, but creating a time for the moon isn’t easy. For one thing, a day on the moon lasts 29.5 Earth days. Time itself also flows differently on the moon, as explained in Albert Einstein’s general theory of relativity, which notes that time moves more slowly in stronger gravitational fields. Because the moon’s force of gravity is weaker than Earth’s, a lunar clock would gain an estimated 56 microseconds (a microsecond is one millionth of a second) compared to Earth clocks every Earth day. That may seem like a small discrepancy, but it’s one that would prove disastrous for any lunar GPS system, which would be extremely reliant on accurate timekeeping. One idea is to synchronize the moon to UTC, or to create a wholly independent lunar time — a framework that could also work well for future human settlements on Mars and beyond. For now, the moon’s time remains mysterious, but soon Earth’s only natural satellite will be brought into the temporal fold.
Media Release/Interesting Facts
