What Time Is It On the Moon? (nature.com) 193
Satellite navigation systems for lunar settlements will require local atomic clocks. Scientists are working out what time they will keep. From a report: It's not obvious what form a universal lunar time would take. Clocks on Earth and the Moon naturally tick at different speeds, because of the differing gravitational fields of the two bodies. Official lunar time could be based on a clock system designed to synchronize with UTC, or it could be independent of Earth time. Representatives of space agencies and academic organizations worldwide met in November 2022 to start drafting recommendations on how to define lunar time at the European Space Research and Technology Centre of the European Space Agency (ESA) in Noordwijk, the Netherlands.
Decisions must be made soon, says Patrizia Tavella, who leads the time department at the International Bureau of Weights and Measures in Sevres, France. If an official lunar time is not established, space agencies and private companies will come up with their own solutions, she says. "This is why we want to raise an alert now, saying let's work together to take a common decision." The most pressing need for lunar time comes from plans to create a dedicated global satellite navigation system (GNSS) for the Moon, similar to how GPS and other satellite navigation networks enable precise location tracking on Earth.
Space agencies plan to install this lunar GNSS from around 2030. ESA approved a lunar satellite navigation project called Moonlight at its ministerial council meeting on 22 and 23 November 2022 in Paris, and NASA established a similar project, called Lunar Communications Relay and Navigation Systems, last January. Until now, Moon missions have pinpointed their locations using radio signals sent to large antennas on Earth at scheduled times. But with dozens of missions planned, "there's just not enough resources to cover everybody," says Joel Parker, an engineer who works on lunar navigation at the Goddard Center.
Decisions must be made soon, says Patrizia Tavella, who leads the time department at the International Bureau of Weights and Measures in Sevres, France. If an official lunar time is not established, space agencies and private companies will come up with their own solutions, she says. "This is why we want to raise an alert now, saying let's work together to take a common decision." The most pressing need for lunar time comes from plans to create a dedicated global satellite navigation system (GNSS) for the Moon, similar to how GPS and other satellite navigation networks enable precise location tracking on Earth.
Space agencies plan to install this lunar GNSS from around 2030. ESA approved a lunar satellite navigation project called Moonlight at its ministerial council meeting on 22 and 23 November 2022 in Paris, and NASA established a similar project, called Lunar Communications Relay and Navigation Systems, last January. Until now, Moon missions have pinpointed their locations using radio signals sent to large antennas on Earth at scheduled times. But with dozens of missions planned, "there's just not enough resources to cover everybody," says Joel Parker, an engineer who works on lunar navigation at the Goddard Center.
china will say that the moon has one time zone (Score:3, Funny)
china will say that the moon has one time zone.
and others will just try to cut it in to there own system.
Indiana has that floating line as well.
Re: (Score:2)
Re: (Score:2)
Since cesium does what it does everywhere, a second can remain a second, and 60 of them can remain a minutes.
But doesn't time itself behave differently in different gravitation?
Re: (Score:2)
Yes, but within every gravitational field time flows "normally" according to the SI definition of a second. It is only when you try to compare clocks running in different kinetic and gravitational frames that strange things start happening.
Re: (Score:2)
you actually find that forced, artificial and loaded retort ... funny?
no, it's not really a question, more of an observation.
Re: (Score:3, Insightful)
Honest question (Score:2)
On the night of a full moon over the prime meridian, when the moon is at the top of its arc, is the center of the visible disc at the same longitude each time?
Re: (Score:2)
No.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Re: (Score:2)
i don't think that's even related to his convoluted (but supposedly honest) question.
Re: (Score:3)
I can't be absolutely sure because of the convoluted wording, but the way I read it is that the GP was asking whether, when the moon is at an apoapsis that lines up with the Earth's prime meridian and also moon opposition to the sun (a full moon), a unique point on the moon is closest to Earth.
That doesn't happen, and doesn't happen for pretty much any specific point in either orbit you care to specify, because of libration. That's what libration is. The moon's orbit and rotation aren't perfectly synchronou
Re: (Score:2)
a unique point on the moon is closest to Earth
that's where i think the answer deviates. he means the "center of the visible disc" as a reference of the moon's position in the sky relative to the earth observer, and i assume the orientation (and which specific point of the moon's surface is center at that moment) is irrelevant. mind you, the orbital math for his question escapes me and i'm not even sure he isn't trolling us :'-D
Re: (Score:2)
I assumed he said "centre of the visible disc" because he doesn't know about libration. If you leave that in, the question is tautological.
Lunar song (Score:2)
On the night of a full moon over the prime meridian, when the moon is at the top of its arc, is the center of the visible disc at the same longitude each time?
Would you offer your trachea to the canus lupus with the red rosacea?
Re: (Score:2)
Re: (Score:2)
This is so easy to answer. The time on the moon is "now". It's always "now", and has always been "now".
MUST be one time zone (Score:5, Insightful)
The case for having a single time zone for the Earth only fails because we're used to 0900 being morning, 1200 when the sun is near its highest point, etc etc. On the moon there is no such constraint, so let's go for one now. UTC does seem the obvious solution, though its link to the British Empire may be an issue for the Chinese.
Re: (Score:2)
Re: (Score:2)
When exactly is Earthrise on a tidally locked body that shows is parent body constantly the same side?
Re: (Score:2)
Re: (Score:2)
The moment that the New Earth ends and the Waxing Crescent Earth begins. Obviously.
Re: (Score:2)
Can't they just use Unix Time ?
Why does it matter to a satellite whether it's dark on the ground below it or not?
Re: MUST be one time zone (Score:2)
Re: (Score:2)
>>because we're used to 0900 being morning, 1200 when the sun is near its highest point, etc etc. On the moon there is no such constraint
The moon has sunrise and sunset just like earth. The only difference is that days are about a month long.
Re:MUST be one time zone (Score:4, Insightful)
The problem isn't the time zone. The problem is that *time actually flows at a difference rate* on the moon, because of the difference in the gravitational field. It's not a big difference, but it's going to play hob with things that require split-second accuracy.
Re: (Score:2)
Which would screw up scientific data.
If you run an experiment and it takes 0.02 seconds. Is that 0.02s from the frame of reference of the observer on the moon or from the frame of reference of the earth where the experiment wasn't ran.
Re: (Score:3)
Yeah, I'm trying to think of an argument for not keeping it in sync with UTC, and I can't think of anything. If they keep a different standard, they're going to have to create a bunch of functions (or systems) for converting it to UTC anyway. Might as well just keep it simple until there is a real-world need for a different system (like people waking up in the morning on the moon, which also would be kind of weird).
Re: (Score:2)
use UTC (Score:2)
Yeah, I'm trying to think of an argument for not keeping it in sync with UTC, and I can't think of anything. If they keep a different standard, they're going to have to create a bunch of functions (or systems) for converting it to UTC anyway. Might as well just keep it simple until there is a real-world need for a different system (like people waking up in the morning on the moon, which also would be kind of weird).
If there is a concern about keeping clocks on Luna synchronized to UTC, the National Institute of Science and Technology (NIST) will rent you a clock that is kept within 10 nanoseconds of UTC. Their information doesn't have any requirement for keeping the Disciplined Clock (NISTDC) close to Earth. Check it out [nist.gov].
Re: (Score:3)
Which won't work on the moon. That's the point. A perfect clock will run at different speeds on the moon and on Earth due to relativity.
Re: (Score:3)
Which won't work on the moon. That's the point. A perfect clock will run at different speeds on the moon and on Earth due to relativity.
NIST disciplines the clock so it should still work, just as an NISTDC at high altitude on Earth will still work.
Re: (Score:2)
After looking up at how it works... How are they going to "discipline" it once it's on the Moon and no longer connected to either the Internet or the GPS satellites that it relies on? This is a device for keeping precise time on Earth, used by stock exchanges and such. Space travel is not mentioned in any context linked to it...
Re: (Score:2)
After looking up at how it works... How are they going to "discipline" it once it's on the Moon and no longer connected to either the Internet or the GPS satellites that it relies on? This is a device for keeping precise time on Earth, used by stock exchanges and such. Space travel is not mentioned in any context linked to it...
A station on the near side of Luna will have visibility to lots of GPS satellites, which are in medium Earth orbit. As for Internet accvess, NASA has the Deep Space Netowrk which can carry internet packets to support a manned Lunar station.
If there were GPS satellites for Luna, as is proposed, a control station on the Nearside can keep them synchronized to UTC, and thereby provide UTC to Farside manned stations.
If it turns out that the Nearside surface is too far from Earth to get reliable signals from the
Re: (Score:2)
There's two usages, which are both called time measurement. The one that is kept in sync with the UTC doesn't drift enough to cause synchronization problems. The one where you measure elapsed times to the split nanosecond doesn't need to be synchronized with anything else...that's "synchronized" as in "aligned". You need to know the size of the second quite precisely, but you don't need to tie it into a calendar (except to the degree that that would affect the size of the second).
Re: (Score:2)
There's two usages, which are both called time measurement. The one that is kept in sync with the UTC doesn't drift enough to cause synchronization problems. The one where you measure elapsed times to the split nanosecond doesn't need to be synchronized with anything else...that's "synchronized" as in "aligned". You need to know the size of the second quite precisely, but you don't need to tie it into a calendar (except to the degree that that would affect the size of the second).
NIST claims that the NIST Disciplined Clock is continuously disciplined to UTC(NIST) with a time uncertainty of about 10 nanoseconds and a frequency uncertainty of less than 1 times 10 to the -14 power at an averaging time of one day.
Re: (Score:3)
Re: (Score:2)
Re: (Score:2)
Isn't it easier to say "what time is it in Japan" rather than "what time do people wake up in Japan"?
Re: (Score:2)
Re: (Score:2)
You have to ask one of those two things. There's no way around it. Unless of course you don't want to know.
Time zones are easier. Deal with it.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
There's no way to avoid exceptions. Using UTC doesn't avoid exceptions.
You are trying to avoid the complexity of time but you can't because time is complex.
Re: MUST be one time zone (Score:2)
Re: (Score:2)
Re: (Score:2)
May Need Different Calendars though... (Score:2)
The case for having a single time zone for the Earth only fails because we're used to 0900 being morning, 1200 when the sun is near its highest point
The same applies oto the Moon. The only difference being that the time when the sun nears its highest point can be ~14 days different between two points on the Moon's surface. So you could have the same time zone on a daily basis but you'll need different days instead of hours - so perhaps calendar zones? - for people to be able to tell when it will be light or dark outside which is the reason we have different time zones on Earth.
Re:MUST be one time zone (Score:4, Insightful)
The case for having a single time zone for the Earth only fails because we're used to 0900 being morning, 1200 when the sun is near its highest point, etc etc. On the moon there is no such constraint, so let's go for one now.
The conclusion is correct: people will wake and sleep 29 or 30 times in one solar day on the moon, so it doesn't make sense to peg time there to the sun. So humans should all use one time zone, linked to some zone on earth. That will make it easy to coordinate activity around the moon and also predict when people back home on earth will be awake/asleep, etc. (e.g., people on the East Coast of the U.S. are generally awake at 12:00-04:00 UTC).
However, I disagree with the implication that we should do away with time zones on Earth. It is fairly simple to ask, "what time is it in Chile?" and work from your standard knowledge of working hours when scheduling a meeting. If everyone was on UTC, you'd have to ask "when are working hours in Chile?" and work from that. Not necessarily more complicated, but not any simpler. And with everyone on UTC, if you actually visited Chile, you'd have to keep reminding yourself what time people go to work, eat, sleep, etc., i.e., keep doing time zone math until you become a local. On the other hand, with time zones, if you visit Chile, you just set your clock to local time, and you'll be in sync automatically.
I guess my point about time zones on Earth is that they allow us to use only one unfamiliar piece of information (the time zone offset) when scheduling across zones and none at all when moving to a new zone. If everyone ran on UTC, we'd need to keep track of many pieces of information for each zone -- when is breakfast, when is dinner, when are work hours? -- whether we were scheduling across zones or moving across zones.
The only people who gain anything with universal UTC are the people trying to keep track of time in databases. That may be a majority of people on Slashdot, but it is definitely not in the rest of the world.
Re: (Score:3)
If everyone was on UTC, you'd have to ask "when are working hours in Chile?"
It gets worse than that. If we truly get rid of timezones, then eventually cities that were in the same timezone will most likely start to drift. For example St Louis and Kansas City are in the same timezone, but KC is about 20 minutes behind St Louis when it comes to sun rise and sunset. Without any time zones, people will naturally start to want to drift to solar time to maximize daylight for activities. Not right away, but 15, 20, 30 years after the change, you bet you will see it. So eventually you woul
Re: (Score:2)
I don't think the Chinese care, they already use UTC and the Gregorian calendar.
Japan does too, but also uses emperor eras for years. I actually can't think of any country that doesn't use UTC and a 24 hour clock as the base, and Gregorian dates, off the top of my head. I bet the is at least one.
Re: (Score:2)
Much of SE Asia uses the Buddhist calendar combined with the Chinese Zodiac 12 year cycle. Generally with a country-specific New Year date. In a capital city you'll find lots of people who were educated in the Gregorian calendar, but in most small cities and villages they use the Buddhist calendar exclusively.
Re: (Score:2)
Or we could have the moon use the 13 month International Calendar [rd.com] while we are imposing our world view on a natural object.
Re: (Score:2)
If you take an atomic clock set to UTC from Earth to the Moon and back, you'll discover that it's no longer perfectly synchronized to a similar clock that was on Earth the whole time. Relativity is funny. Synchronizing clocks across the light-second distance (which also varies) would also be a challenge.
This won't matter a whole lot for human-readable things like clock and calendar displays, but it will for science (and maybe GPS satellites etc). The Moon probably will need its own "Lunar-UTC" standard and
You're Stupid (Score:3)
Problem #1: GNSS needs to know what "time" it is on the astronauts watches. Because Relativity. Solution: That's now how this works. That's not how any of this works. Don't you have a World Clock app on your smartphone?
The satellites and receivers will tick their clocks and calculate the relativity (gravity/motion adjustment) without translating into human timezones. When the humans want to know what time it is, the devices will translate it into whatever timezone you wish.
Problem #2: Previous lunar missions used earth-time on their watches. And those were kept in sufficiently in sync even though they do tick at different rates. Solution: Those were mechanical clocks. Now we have electronic ones that can automatically compensate. You know, like the GNSS are doing. The GNSS that these same wristband clocks will already be listening to for navigation. So you'll have a magic compensating watch on your wrist, which will also get a backup sync from the satellites.
Problem #3: "There aren't enough resources". Solution: Create some hype about tangential issues that is meaningless but sounds like a dire problem that must be addressed before the possibility that the various human settlemenets by different countries on the lunar surface decide they are in different times zones or something, which would be a disaster. SEND MORE MONEY NOW PLEASE.
By Your Command (Score:2)
The time units on the moon will be displayed in Yearens and Centons and Elons.
Re: By Your Command (Score:2)
So say we all
Re: (Score:2)
You are mixing your series. Time units of Yarans and Centons were in the original but not the 2003 reboot. "So say we all" was only in the reboot.
Political not Scientific Issue (Score:2)
Re: (Score:3)
Just the opposite. This isn't about time zones or when people wake up, or anything else. It's about how the time standard that nobody actually sees works.
Choice 1: sync lunar standard time with UTC (or TAI rather). Pro: timestamps on Earth and the moon are synchronous. Con: local atomic clocks don't count time to the standard, and clocks that do count to the standard can't be used for measuring intervals accurately.
Choice 2: Define a local lunar standard. Now you need to convert timestamps, but you can use
Magic compensation can obscure problems (Score:2)
I'd want to take a careful methodical look at the implications of having different definitions of a second in different places.
TDB is the same everywhere and there's no-charge software to do conversions, but it has very few users.
why not GMT? (Score:2)
It just seems to be an obvious choice to me to use GMT. ("zulu time" or whatever you want to call it) And no I don't live in England. It'll simplify things when trying to adjust for earth time since you'll only have to consider the earth timezone, and not some additional moon time zone.
There are really only two reasons for time zones - to keep time the same when not traveling east-west, and to maintain daylight orientation when traveling east-west. And neither of these will be issues with the moon. The
This isn't primarily about time zones (Score:2)
It's about time itself, and how it is different in the moon's lower-gravity environment than on the earth's surface.
Defining lunar time is not simple. Although the definition of the second is the same everywhere, the special theory of relativity dictates that clocks tick slower in stronger gravitational fields. The Moonâ(TM)s gravitational pull is weaker than Earthâ(TM)s, meaning that, to an observer on Earth, a lunar clock would run faster than an Earth one. Gramling estimates that a lunar clock would gain about 56 microseconds over 24 hours. Compared with one on Earth, a clockâ(TM)s speed would also subtly change depending on its position on the lunar surface, because of the Moonâ(TM)s rotation, says Tavella. âoeThis is a paradise for experts in relativity, because you have to take into account so many things,â she adds.
Re: (Score:2)
Re: (Score:2)
Slashdot isn't really a site for tech nerds anymore, it's just for political bickering. And there's nothing like timezones and daylight savings time to kick off political bickering.
Re: (Score:2)
Re: (Score:2)
Not quite. The Special Theory of Relativity deals with one special case: unaccelerated linear motion. (That's why it's called "special," if you were wondering.) It only covers time dilation caused by velocity. For gravitational effects, you need General Relativity.
Re: (Score:2)
That's a very common misperception. Special relatively includes accelerated frames: https://math.ucr.edu/home/baez... [ucr.edu]
In special relatively, accelerating frames are a special case. In general relativity they are not.
Re: (Score:2)
Re: (Score:2)
Both special and general relativity have effects on GNSS satellites, because their orbital velocity is faster than a receiver (observer) on the ground, and because the satellites are further away from the gravitational field of the receiver.
Both of these effects will be different for GNSS satellites around the Moon, because they'll be in different orbits (so different orbital velocity relative to the Moon's surface), and they'll be affected differently by the Moon's different gravity.
I guess already a secon
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Does it matter? (Score:2)
Exercising my google fu, it appears the moon rotates every 27 days. So now what? Will the moon have 24 hour (ish) hours to account for 1 sunrise and 1 sunset? If it moves so slow, is it really practical to try to sync up a clock with time zones? Especially since it would be "all over the place" as it relates to earth time/time zones. It s not like you can say "if it is 4P UTC the time on the moon (based on its rotation) is ___________. "
I think you set it to UTC across the entire surface, it would make sens
natural rate (Score:2)
The article says that atomic clocks on Luna tick at a different "natural rate" from clocks on Earth. This is nonsense: atomic clocks do not have a natural rate. The SI second is defined as he duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom when it is at rest with respect to the Earth, at a temperature of 0 Kelvin, and located at mean sea level. There is nothing natural about 9 192 631 770. To m
Re: (Score:2)
The article says that atomic clocks on Luna tick at a different "natural rate" from clocks on Earth. This is nonsense
Gravity is less on the moon, thus relativistic effects will cause clocks to tick faster there than they do on the surface of the Earth. Time does not move at the same speed in all reference frames! It depends on relative speed and spacetime curvature.
Now is the time ... (Score:2)
Re: (Score:2)
"cesium 133 atom when it is at rest with respect to the Earth, at a temperature of 0 Kelvin, and located at mean sea level."
An atomic clock must be expensive if it has to be at 0 Kelvin on Earth at sea level...
Re: (Score:2)
"cesium 133 atom when it is at rest with respect to the Earth, at a temperature of 0 Kelvin, and located at mean sea level."
An atomic clock must be expensive if it has to be at 0 Kelvin on Earth at sea level...
I think they compensate for the temperature and altitude.
Re: (Score:2)
Fudging the periods/second of an atomic clock to make seconds longer on the Moon in an attempt to match the length of a second on Earth is silly. Anything that happens on the Moon happens in that particular reference frame, so something that takes exactly a second would take exactly 9 192 631 770 periods on a cesium clock sitting next to it. There aren't too many things that require such precision, but on the off chance that someone's doing Special Time Science(tm) on the Moon I'd be willing to live with my
Who cares? (Score:2)
There are many problems in this world. A time standard for a non-existent moon base is not one of them.
We'll just pick one, maybe UTC. Days on the moon last ~28 days so it really doesn't matter. The more interesting question (which still doesn't matter, but is at least interesting to consider) is what standard a Mars base would use. A day on Mars is a bit less than 25 hours, so matching a day on earth would be strange.
Re: (Score:2)
There is for Mars, like the Darian Calendar [wikipedia.org], although for timekeeping I'd prefer the Mars Trilogy system, see https://en.wikipedia.org/wiki/... [wikipedia.org] clocks retain Earth-standard seconds, minutes, and hours, but freeze at midnight for 39.5 minutes
We've come far (Score:5, Insightful)
I recall reading a SciAm article about how when the first GPS satellite hardware was being launched back in the '60s. It turns out that enough of the engineering staff did not have faith that relativity was "real," so the project had to include a software switch that would turn on or off the adjustment required by the relativity equations.
To me the story is a good illustration of the dividing line between science and engineering.
Now that the science is settled, we now have to decide what to do about it. I honestly have no idea which approach would be better.
Re:We've come far (Score:5, Interesting)
I recall reading a SciAm article about how when the first GPS satellite hardware was being launched back in the '60s. It turns out that enough of the engineering staff did not have faith that relativity was "real," so the project had to include a software switch that would turn on or off the adjustment required by the relativity equations.
Similarly, when the Stanford Linear Accelerator was built, there was some uncertainty about whether an electron, moving at nearly the speed of light, would fall as it traversed the two-mile-long accelerator. There was no way to do a software switch, so the physicists convinced the engineers to build the device assuming that electrons do feel gravity. It turned out the physicists were right.
Irrelevant / Non-issue (Score:2)
Anyone drumming up controversy over this topic is a complete idiot. Our current technologies have no trouble tracking time/position between different relativistic reference frames.
For a great many years to come, anyone working and living on the moon will keep schedules according to whatever is optimal for the country hosting the lunar expedition. By the time anything more complex would be necessary, such as standardizing work schedules between multiple teams, I'd suspect the desired changes would be rather
Are they stupid? (Score:2)
Even considering the use of lunar time independent of Earth time is really dumb for MANY reasons. In fact it's scary to think about the mental state of leaders that would even suggest doing that. 1. The astronauts will be dealing with Earth a lot and having to convert their time (lunar 27-day?) to an Earth 24 hour clock would be idiotic and prone to (potentially disastrous) error. 2. Humans operate on a 24 hour clock (for now), we evolved to live by a 24 hour clock .. lunar colonists will still be human, w
evening (Score:5, Funny)
Re: (Score:2)
Of course, if it's 9 o'clock then you'll always be in time for morning tea.
Re: (Score:2)
Always 4:20 [wikipedia.org].
Re: (Score:2)
AKA "Martini Time". I like it.
Re: (Score:2)
It should also be permanently April 25th there. Because itâ(TM)s not too hot, not too cold. All you need is a light jacket.
Please give us all a break ... (Score:2)
You definitely want to synchronize the passage of human-scale time to UTC so that all humans have one common clock based upon which they can all accurately coordinate their actions.
If you instead allow human-scale clocks on the moon to run at their natural rate according to the SI definition of a second, then you will simply be creating heartache for everyone else down the line as calendars on Earth and Moon slowly become dissociated from one another. Please don't do that without very, very good reason.
Obvi
Re: (Score:2)
To clarify, there are two independent issues here:
1) Disciplining clocks to mark the passage of time on Moon the same way they do on Earth in a synchronized fashion -- effectively ignoring / compensating for relativistic gravitational effects.
2) Choosing a particular Earth timezone that (all) people on the Moon will use.
To me, doing anything other than 1) is just plain crazy. I don't see any good reason for not keeping in-sync with the passage of time on Earth. The relative relativistic effects are tiny and
Good heavens, just look at the time (Score:2)
https://knowyourmeme.com/memes... [knowyourmeme.com]
New time zone completely! (Score:2)
In all seriousness time is an earth-centric thing. Measurement has to serve a purpose, and the 24-hour time zone is useful if you're on Earth, but perhaps there should be a super-time zone system that's solar system centric.
LST: Lunar Standard Time = GMT (Score:2)
UTC just like the ISS (Score:2)
There's really no reason to not continue using Earth UTC, just like they use on the ISS right now. Arguably, the Chinese would probably prefer China Standard time.
Arguing about relativity is just silly, IMHO. Until there is a large enough population on the Moon to care, staying coordinated with _some_ time zone on Earth is the most practical solution. Given that a day on the Moon lasts 28 Earth days, there isn't really any natural day/night cycle that fits with human biology. Plus, most people on the Moon a
Oh no! (Score:2)
If an official lunar time is not established, space agencies and private companies will come up with their own solutions, she says
Oh no! People might come up with organic solutions that work well for them!
Most important consideration (Score:2)
Whatever they decide to do - it needs to be consistent with the conventions used on shows like Futurama and Space: 1999.
Retconning is a pain in the a**.
Looking forward to another daylight savings time (Score:2)
Because someone will say "sure would be nice to have a bit more daylight during certain times of the year..."
A lot of people aren't getting this (Score:3)
I'm disappointed that a lot of people here don't seem to get why this is a problem. GPS relies on very precise timing in order to calculate a position based on how long it took a signal to reach you. The signal encodes a time, and there are atomic clocks onboard the satellites. That's how important it is have not only accurate, but precise timing.
Blah, blah, blah "what difference does a second make?". More than you probably think. We're using some really amazing stuff here that requires very precise timing to work right. If we don't get this right, systems that work without human intervention, such as automated docking could be way off.
If we don't get agreement, then the individual systems might work, but then even if we're all using SI units we're not using the same convention so we'll end up with fusterclecks like, "Do you mean SpaceX docking coordinates, Chinese coordinates, or American?" and next thing you know the automated docking system on the resupply mission goes sailing past the gate 10 meters to the left and crashes in to the main solar array because somebody fat-fingered that.
Re:A lot of people aren't getting this (Score:4, Insightful)
The (interesting) issue is that the gravitational potential on the moon is different than on the earth, so due to general relativity effects, time moves at a different rate - by enough to care about. We could come up with some special case solution for the moon, but its a far more general problem that time is not a well defined things in different gravitational potentials. There is no "right" answer or even an obvious "best" answer. If we imagine lots of science in different locations in space, this will become ever more important.