Timekeeping on the Moon is a trickier problem than you might think.
Due to the wonky principles predicted in Einstein’s theory of relativity, time itself moves ever so slightly faster on the surface of the Moon than it does on our planet.
The difference is extremely subtle — just 56 to 57 microseconds faster than what atomic clocks on Earth tick at each day.
GPS systems already account for this — but what if we were to set up a GPS system on the Moon?
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It’s not as simple as you might think to keep time on the moon.
It goes beyond the simple fact that one “day” on the Moon is equivalent to roughly 29.5 days on Earth, or that it lacks the diurnal cycle that Earth has.
Time itself appears to move ever so slightly more quickly on the surface of the Moon than it does on Earth because of the quirks in relativity predicted by Einstein.
Just 56 to 57 microseconds faster than Earth’s atomic clocks tick every day makes a very small difference. However, those distinctions become significant when discussing the execution of scientific missions and the launch of spacecraft, all of which call for incredibly accurate computations.
Now, a new study that was just published in the journal The Astronomical Journey describes a method for balancing lunar and Earth time, which according to the study’s authors may be crucial for future space exploration as well as Moon exploration.
An explanation of the work was provided by study co-author Bijunath Patla, a physicist at the National Institute of Standards and Technology. “It’s like having the entire Moon synchronized to one ‘time zone’ adjusted for the Moon’s gravity, rather than having clocks gradually drift out of sync with Earth’s time.”.
GPS systems are one domain where the researchers point out that synchronized timekeeping could be advantageous. For Earth to function, these satellite-based networks need a universal time standard. However, they are also victims of relativity.
At higher altitudes, where the Earth’s pull is slightly weaker, satellites move slightly faster in time than we do on the planet’s surface. This is essentially because, to simplify a lot of very complicated science, stronger gravitational effects cause time to go slower.
Such capabilities, the researchers argue, will be essential to make lunar exploration more efficient in the future. GPS systems already account for this, but what if we were to set up a GPS system on the Moon?
However, this also necessitates balancing the faster timekeeping on the Moon with the GPS networks on Earth, in order to plan flights between the two celestial bodies with precise landing locations in mind, or carry out concurrent experiments on both surfaces.
The essence of the researchers’ approach, which is based on utilizing the center of mass between the Earth and the Moon as a reference frame, is that it involves a great deal of intricate math.
As “time transfer links” between Earth and the Moon, clocks positioned in orbit at Lagrange points—points in space where a small object under the gravitational pull of two larger ones can stay in the same position relative to them—would be useful because, according to the researchers’ study, these orbital sweet spots “provide a low acceleration noise environment” that makes it simple for scientists to adjust for relativity.
The researchers take into consideration a variety of factors that take into account the tidal influence of other planets and the Sun, since there are other factors at work in addition to the gravity of those two celestial bodies. They must also take into consideration the Earth’s and the Moon’s rotations, in addition to dozens of other mind-boggling cosmic puzzles.
The bottom line, though, is that the researchers claim that their work can be applied to other bodies, such as Mars; thus, it may be used for deeper space exploration in addition to serving as a potential solution to our temporal Moon issues.
Additional information about the moon: Biden gives NASA instructions to determine the lunar time.
