Have you ever thought what time it is on the moon? Soon there will be an answer to this question as the moon is going to get its own time reference system.
The US White House has officially directed the National Aeronautics and Space Administration (NASA) to create a time standard for the Moon and other celestial bodies, which different international bodies and private companies can use to coordinate their activities on the lunar surface.
According to a report first published by Reuters, the head of the White House Office of Science and Technology Policy (OSTP) has instructed the space agency to work with other parts of the U.S. government to finalise the strategy by the end of 2026 for establishing a Coordinated Lunar Time (LTC). The prospect of a lunar time-zone comes as the U.S. and private companies are rushing to send astronauts to the moon in the coming years.
How Does Earth’s Standard Time Work?
Most of the clocks and time zones — a geographical region which uses the same standard time — of the world are based on Coordinated Universal Time (UTC), which is set by the International Bureau of Weights and Measures in Paris, France. UTC is essentially internationally agreed upon standard for world time.
It is tracked by a weighted average of more than 400 atomic clocks placed in different parts of the globe. Atomic clocks measure time in terms of the resonant frequencies — the natural frequency of an object where it tends to vibrate at a higher amplitude — of atoms such as cesium-133. In atomic time, a second is defined as the period in which a caesium atom vibrates 9,192,631,770 times. As the vibration rates at which atoms absorb energy are highly stable and ultra-accurate, atomic clocks make for an excellent device for gauging the passage of time.
To obtain their local time, countries need to subtract or add a certain number of hours from UTC depending on how many time zones they are away from 0 degree longitude meridian, also known as the Greenwich meridian. If a country lies on the west of the Greenwich meridian, it has to subtract from the UTC, and if a country is located on the east of the meridian, it has to add.
Why is the Lunar Standard Time Needed?
UTC cannot be used to determine time on the Moon. The time zone in space is not quite the same as on Earth due to differences in gravity and other factors. Time on the moon moves 58.7 microseconds, or millionths of a second, faster each day than on Earth. This is because of Einstein’s Theory of General Relativity which tells us that gravity bends space and time. As there is less gravity on the Moon, time ticks slightly faster there relative to the time on the Earth.
The discrepancy may seem small but it can create problems for situations such as a spacecraft seeking to dock on the Moon, data transferring at a specific time, communication, and navigation. Currently, handlers of each lunar mission use their own timescale that is linked to UTC.
Several countries, including India, are looking to inhabit the Moon in the coming years. While NASA’s Artemis program aims to send astronauts back to the lunar surface by around September 2026, China has announced plans to land its astronauts by 2030, and India intends to arrive by 2040. There are also proposals to build a long-term human outpost on the Moon. Therefore, a unified lunar time standard is much needed.
How will LTC be Established?
The specifics for creating a time standard for the Moon are not clear yet. An OSTP official, however, told Reuters that like on the Earth, atomic clocks can be deployed on the lunar surface to set a time standard.
According to a 2023 report by the journal Nature, there will be a need to place at least three atomic clocks on the lunar surface that will tick at the moon’s natural pace, and whose output will be combined by an algorithm to generate a more accurate virtual timepiece. These clocks have to be placed on the moon at different locations since the moon’s rotation and even local lumps of mass beneath the crust of the moon affect the flow of slightest time.
NASA is not the only government agency working to devise a universal timekeeping system for the moon. The European Space Agency has also been developing a lunar time zone to help aid future lunar explorations. The White House memo says that establishing a new lunar time zone will require international agreements through “existing standards bodies” and among the 36 nations participating in the Artemis Accords, which outlines guidelines for activities in space and on the moon.
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