What time is it on the moon? Scientists want to create a ‘shared’ lunar clock

ASPEN PFLUGHOEFT

February 28, 2023

Photo from Ganapathy Kumar via Unsplash

When the moon hits your eye like a big pizza pie that’s — actually 07:36 lunar time.

Or at least, it hypothetically could be.

Most of us admire the moon, photograph it and occasionally sing a song about it. We don’t often think about lunar timekeeping.

But what time is it on the moon? Does the moon have its own lunar timezone? How do we tell time there? Scientists are grappling with these mind-melting questions, and some have an idea how to answer them.

“A new era of lunar exploration is on the rise, with dozens of Moon missions planned for the coming decade,” the European Space Agency (ESA) said in a Monday, Feb. 27, news release.

To allow these lunar missions to coordinate and communicate with each other, the moon “needs a shared clock” and “common timing system,” the agency said on Twitter.

Currently, the moon does not have an independent timekeeping system. Instead, previous missions to the moon used their timezone from Earth, ESA officials said. Astronauts would be synchronized with Houston, Moscow or whatever timezone in which the mission headquarters was located.

With more lunar missions on the horizon, that system won’t work, the ESA said. Instead, space organizations are trying to decide on a standardized way to keep time on the moon. This timekeeping system will also aid in navigation on the lunar surface and within the lunar orbit.

A standardized timekeeping system and, by extension, navigation system have been established for Earth. The same can be done for the moon, Jörg Hahn, an ESA advisor for the lunar timekeeping project, said in the release.

“The experience of this success can be re-used for the technical long-term lunar systems to come,” Hahn said, “even though stable timekeeping on the Moon will throw up its own unique challenges.”

Time passes at different rates on Earth and on the moon because of variations in gravity, ESA officials said. Clocks on the moon tick faster than clocks on the Earth because of the decreased gravitational pull. For this same reason, clocks tick at different rates on the lunar surface and the lunar orbit.

Accounting for these different rates of time is one of the challenges scientists face in developing a lunar clock.

A “shared” lunar clock faces an additional set of challenges, officials said in the release. Scientists have a lot of complicated questions left to answer, such as:

• Who sets and maintains time on the moon? One organization? Multiple organizations?

• Will lunar time be independent of Earth time? Or will the two be linked and kept in sync?

• In practice, what technology will need to be built or developed to keep time on the moon?

• How can a lunar timekeeping system be made practical for astronauts?

• What will the reference point be for setting time and, by extension, for lunar navigation?

“Throughout human history, exploration has actually been a key driver of improved timekeeping and geodetic reference models,” ESA official Javier Ventura-Traveset said in the release. “It is certainly an exciting time to do that now for the Moon.”

Solving the challenge of a lunar timekeeping system has another benefit, ESA official Bernhard Hufenbach said in the release. “Having established a working time system for the Moon, we can go on to do the same for other planetary destinations.”

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