What’s all this about NASA working on a time zone for the moon?
Time zones are important. They make it easy to know that if it’s 3pm in New York, it’s noon in Los Angeles. But what time is it on the moon? In April the the Biden-Harris administration asked NASA comes up with a time zone exclusively for the moon.
A lunar time zone would be beneficial, among other things, for making accurate calculations when planning lunar missions. That’s why NASA started work on Coulated Lunar Time, which would be shortened to LTC, even though the letters aren’t quite in that order.
The timing setup could come in handy for the space agency Artemis Missions in the works for years to come. The Artemis III mission, which would return humans to the lunar surface for the first time since the Apollo spaceflights more than 50 years ago, is currently scheduled for launch no earlier than September 2026.
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According to NASAThe LTC plan is intended to standardize time, similar to Coordinated Universal Time, the global time standard that regulates Earth’s clocks. UTC is determined by the weighted average of atomic clocks on Earth. LTC will be determined by the weighted average of atomic clocks on the moon. It seems simple enough, but NASA still needs to make some calculations before it can start sending clocks to the moon.
The biggest problem NASA will have to address is best explained by Einstein’s theories of relativity. Basically, 1 second on Earth is slightly faster than 1 second on the moon, due to differences in gravity and speed.
This effect is called time dilation, and the time difference is about 56 microseconds per day, or just over 20,000 microseconds per year. For reference, a single human blink lasts on average between 100,000 and 350,000 microseconds.
Although this variation over time is imperceptible to humans, it is of great importance for space work. NASA says this small time difference could disrupt calculations enough to jeopardize future missions.
“For something traveling at the speed of light, 56 microseconds is enough time to travel the distance of about 168 football fields,” said Cheryl Gramling, timing and standards leader at NASA. “If someone were orbiting the moon, an observer on Earth who did not compensate for the effects of relativity for a day would think that the astronaut orbiting the moon was about 168 football fields away from where the astronaut actually is located.”
NASA scientists are working on the problem and are facing a deadline. The White House wants the lunar time zone to be known by December 31, 2026. Even time zone projects, it seems, have a time limit.
