Time on the Moon runs faster than on Earth by 56 microseconds. This discrepancy can potentially cause positioning errors of up to 17 kilometers each day.
A research team from the Jet Propulsion Laboratory at the California Institute of Technology (Caltech) has calculated the relative speed of time on the surface of the Moon, Earth, and the barycenter of the Solar System—where the planets, moons, and stars orbit.
Future lunar missions require Coordinated Lunar Time (CLT) – (Photo: NASA).
The researchers found that time on the surface of the Moon drifts faster by 0.0000575 seconds per day compared to Earth. In simpler terms, it would take 100,000 days (approximately 274 years) for a person on the Moon to age 5.75 seconds more than someone on Earth.
According to theoretical physicist Bijunath Patla from the National Institute of Standards and Technology (NIST) in the U.S., this occurs because the Moon’s motion relative to our motion causes clocks to run slower compared to Earth’s standard.
However, the Moon’s lower gravity causes clocks to run faster. “These are two conflicting effects, and the result is a difference of about 56 microseconds each day,” Patla explained.
Although a difference of 56 microseconds is extremely small by human standards, it is crucial for space missions that require high precision, as well as for ensuring communication between Earth and the Moon.
“When it comes to navigation, a 56 microsecond delay in one day between a clock on the Moon and one on Earth is a significant difference,” shared Cheryl Gramling, a systems engineer at NASA.
It will take many years or even decades before the Moon has enough people and robots to necessitate this level of measurement precision. Nevertheless, scientists and engineers have already recognized the importance of establishing a standard lunar time framework.
Without this calculation, future lunar exploration missions could encounter significant issues, according to IFLScience on July 10.
The time discrepancy between Earth and the Moon is critical for space missions requiring high precision (Photo: Getty).
Currently, there is no unified time zone on Earth’s satellite. This poses a problem for the National Aeronautics and Space Administration (NASA) and other space agencies, as humanity aims to establish bases on the Moon and Mars.
Uncrewed missions use the time corresponding to the origin of the spacecraft executing the mission, while Apollo missions utilized Ground Elapsed Time (GET)—measured from the moment of launch. As the Moon becomes more crowded (with robots and potentially humans), several issues will arise that the U.S. hopes to address by establishing Coordinated Lunar Time (CLT).
According to new research, establishing a standard lunar time is essential for synchronizing activities and operations of landers, rovers, and orbiting spacecraft on the Moon. Particularly, the activities of docking, storing, and landing of spacecraft require extremely precise timing.
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Coordinated Lunar Time Still Not Established Although the new research has accurately calculated the time on the Moon compared to Earth, NASA and other space agencies will need to discuss further before officially establishing Coordinated Lunar Time. Earlier in April, the head of the White House Office of Science and Technology Policy (OSTP) sent a memo requesting NASA to work with other agencies, both domestic and international, to establish a reference frame centered on the Moon. NASA has until the end of 2026 to establish Coordinated Lunar Time (CLT)—a time reference framework completely centered on the Moon. |
