NASA To Develop Lunar Time Standard for Exploration Initiatives

NASA will coordinate with U.S. government stakeholders, partners, and international standards organizations to establish a Coordinated Lunar Time (LTC) following a policy directive from the White House in April. From a report: The agency's Space Communication and Navigation (SCaN) program is leading efforts on creating a coordinated time, which will enable a future lunar ecosystem that could be scalable to other locations in our solar system. The lunar time will be determined by a weighted average of atomic clocks at the Moon, similar to how scientists calculate Earth's globally recognized Coordinated Universal Time (UTC). Exactly where at the Moon is still to be determined, since current analysis indicates that atomic clocks placed at the Moon's surface will appear to 'tick' faster by microseconds per day. A microsecond is one millionth of a second. NASA and its partners are currently researching which mathematical models will be best for establishing a lunar time. To put these numbers into perspective, a hummingbird's wings flap about 50 times per second. Each flap is about .02 seconds, or 20,000 microseconds. So, while 56 microseconds may seem miniscule, when discussing distances in space, tiny bits of time add up.

Why not UTC?

[bradley13]

It's in the name: "universal". Sure, you have toake minor corrections for gravity. We manage that for satellites, so surely we can manage it for a really big satellite?

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[penguinoid]

There's no such thing as "universal time", that's just completely incompatible with General Relativity. Fundamentally the rate at which clocks tick depends on the length of the path they traveled, so not only do clocks in different circumstances tick differently, but in general bringing clocks together will show them to be unsynchronized. It's a small effect for the Earth and Moon, but not one there's any particular way to fix, so we have to arbitrarily pick a kludge and agree to it, also our clocks are rea

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[zlives]

i didn't realize energy transitions of electrons in the atomic shell of chemical elements was affected by length of the path of clock ticks

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[SteelCamel]

They aren't - time is. Everyone will see their own atom ticking out perfectly timed transitions, and everyone else's atoms ticking at the wrong speed. Who is right? They all are. There's no absolute time, everywhere - down to atomic level - has its own.

It's reaching the point where UTC is getting a bit fuzzy on Earth - the most accurate atomic clocks now tick measurably differently due to gravity and the Earth's rotation. The best you can do is take an average, call that "universal" time, and then try and w

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[penguinoid]

It's easier to see time dilation with Einstein's light clock: a ray of light bouncing back and forth in a box. A moving observer would see the light taking a longer path (diagonal), and with a constant speed of light means their clock is ticking slower. A similar effect occurs with gravitational acceleration, an observer in different gravity would see the light taking a longer, curved path. A clock on Earth would be distorted by Earth's gravity, centrifugal force from the Earth's rotation, and Earth's motio

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[RoccamOccam]

What if we all used a selected group of pulsars as the universal (or galactic) clock?

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[JBeretta]

Pretty sure speed is a bigger factor than distance when it comes to time-dilation.

But I though NASA buildings were crumbling....

[will4]

So which is it, NASA building falling down or we've got money for a luxury project for years (decades?) in the future when men land on the moon again?

So what;s the priority?

Central message

[will4]

Government agencies, especially in science, medicine, space and military always are crying wolf about running out of money / death / destruction / fear / women and children affected / etc / etc.

when in reality they have a sprawling set of haphazardly managed project, programs, facilities and inventories each of which is of 'national importance' and could not ever ever ever have a reduced budget or cut in funding - even cuts in the rate of growth from baseline budgeting.

And they have a PR team who has the mi

Gotta keep ...

[PPH]

... those railroads on schedule.

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[billyswong]

Lunar Time is not about "what time is it on Earth". Imagine a GPS satellite constellation for Moon. They are going to sync with this new LTC, not UTC. Similar for future celestial bodies to be colonized.

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[laughingskeptic]

That is backwards -- which is how we did it on Earth because our time keepers were very worried about what time meant for astronomical observations. We don't need to do that for the Moon. We can let the geolocation satellites of the Moon define time for their purposes.

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[billyswong]

Those "geolocation satellites of the Moon" need to synchronize time together right? The clock they synchronize towards is going to be the new Coordinated Lunar Time, not UTC.

Computing and smearing the relativistic effect from Earth UTC may look doable for Moon, but things will go ugly soon when you project the same scheme for Mars, Venus, Titan etc. They are varying their distance from Earth a lot. Putting such smearing logic within the geolocation satellite system is going to be error-prone.

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[laughingskeptic]

The smearing is an effect of the laws of physics, not an algorithm.

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[billyswong]

You need an algorithm to implement the smearing, especially when you are not on a fixed height orbit around Earth. The physics effect is not a constant factor. Without sophisticated algorithm, atomic clocks on satellite around Moon cannot report UTC.

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[necro81]

This is completely unnecessary. If scientists on the moon need super accurate times, they can do the same thing scientists on earth do and buy something like this https://www.microchip.com/en-u [microchip.com]... which is free of network latency issues.

The fundamental problem though is that, while entirely consistent for experiments on the lunar surface, the "ticks" coming out of that time reference will not agree with the "ticks" coming from any clock on Earth. For phenomena that are confined to the Moon (which is clos

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[ceoyoyo]

Lunar GPS systems are in advanced planning: https://www.wired.com/story/mo... [wired.com]

You don't technically need to define a unified time standard to implement GPS, but it makes things a lot easier and it pretty much pops out for free once you implement all the things that are required.

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[mydn]

It's likely so that it is consistent with the way that Universal Time is abbreviated (Coordinated Universal Time is abbreviated UTC). From Wikipedia https://en.wikipedia.org/wiki/Coordinated_Universal_Time#Etymology [wikipedia.org]:

The official abbreviation for Coordinated Universal Time is UTC. This abbreviation comes as a result of the International Telecommunication Union and the International Astronomical Union wanting to use the same abbreviation in all languages.[4] The compromise that emerged was UTC,[5] which confo

Is this related to cislunar time?

[mmell]

So, the same exact well understood spatial distortions that affect the flow of time on Earth's surface (which have to be accounted for if GPS is to work) also apply on the moon, but at only a fraction of the force. It was accepted as back in the sixties when we were only beginning to measure time with the kind of accuracy needed - and that with rooms full of heavy, bulky, delicate equipment - that time would flow differently on the Moon than it does on Earth. If you're planning to stay on Earth, no troubl

China will happily ignore it

[BigFire]

All of China runs on Beijing Standard Time, no exceptions.

Time passes slower when you visit your relatives..

[maudlins11]

And the far side cartoon where Einstein proves time = money

WTF

[skogs]

If only we had some sort of computer protocol that could synchronize clocks that drift slightly due to gravity. Barring the creation of that impossible technology, perhaps we could create some sort of space based clock protocol to fit our needs. That too is probably impossible.

I guess that's it. Throw away the watches. You will stay awake on the moon as long as the sun is up. You will sleep as long as it is down. While people on earth go through 365 days a year, you'll only age 13 days.

Really...UTC, coo