No the second is still 9192631770 hyperfine transitions of Cs-133 on the moon and that’s the same length of time at least unless you want to severely annoy physicists by implying that the laws of nature aren’t constant throughout the universe. It’s just that from our perspective it looks like time is flowing differently there.
You are correct that if you are on thee moon and have a cs-133 atom with you is second will take that many transitions. And if you do the same thing on Earth, a second will take the same number of transitions.
But things get weird when you are on earth and observe a cs-133 atom that is on the moon. Because you are in different reference frames, you are traveling at different speeds and are in different gravity wells time is moving at different rates. This means that a cs atom locally will transition a different number of times in a second from your point of view on Earth vs one you are observing on the moon.
And it would all be reversed if you were on the Moon observing a clock back on the Earth.
They already have to account for this with GPS satellites. They all have atomic clocks on them but they don’t run at the same speed as clocks that are on the ground. The satellites are moving at a great speed and are further from the center of the earth than us, so the software that calculates the distance from your phone to the satellite have to use Einstein’s equations to account for the change in the rate of time.
So, in this case a moon timezone, and more generally a “space timekeeping framework” makes sense because time actually moves at a different speed on the moon, so epoch times wouldn’t actually stay in sync.
If the goal of “time” is to make it easier to reason about simultaneous things, then space makes that way more complicated.
It’s just tricky to condense that into a headline that conveys the point.
I suspect that won’t help. The reason the Moon needs a time zone is because of gravitational time dilation, time literally runs slower down here on Earth’s surface relative to the Moon’s surface. A computer on the Moon gains an extra 58.7 microseconds each Earth day, so if you’re programming something that’ll be running on Lunar time you’ll need to account for that.
The point of the lunar time zone is not to have a specific UTC offset like other timezones. The moon would have its own set of atomic clocks, and time could be coordinated with earth based on ratio instead of offset.
They’re not going to be maintaining literal atomic clocks on the Moon for this. They’ll apply a mathematical adjustment to UTC based on what the physics calculations say is happening. The details of that adjustment are what NASA has yet to develop. It could involve subtracting a “leap second” from lunar time at intervals, leap seconds are already used for keeping UTC in sync with the solar time so it’s an established process. Or maybe they’ll just let Lunar time continue drifting relative to Earth, in which case there’ll be a different “epoch” on each.
They probably actually will end up with atomic clocks on the moon, or at least in close lunar orbit. If the plan is to have something like gps on the moon, that’s a first step.
That’s it, I’m only using epoch from now on, that’s enough of your time zone shenanigans
Except the length of a second is different on the moon because of relativity. So even utc is wrong.
Yep, and the math gives different results based on if you’re on the moon or on earth.
No the second is still 9192631770 hyperfine transitions of Cs-133 on the moon and that’s the same length of time at least unless you want to severely annoy physicists by implying that the laws of nature aren’t constant throughout the universe. It’s just that from our perspective it looks like time is flowing differently there.
You are correct that if you are on thee moon and have a cs-133 atom with you is second will take that many transitions. And if you do the same thing on Earth, a second will take the same number of transitions.
But things get weird when you are on earth and observe a cs-133 atom that is on the moon. Because you are in different reference frames, you are traveling at different speeds and are in different gravity wells time is moving at different rates. This means that a cs atom locally will transition a different number of times in a second from your point of view on Earth vs one you are observing on the moon.
And it would all be reversed if you were on the Moon observing a clock back on the Earth.
They already have to account for this with GPS satellites. They all have atomic clocks on them but they don’t run at the same speed as clocks that are on the ground. The satellites are moving at a great speed and are further from the center of the earth than us, so the software that calculates the distance from your phone to the satellite have to use Einstein’s equations to account for the change in the rate of time.
Relativity is weird.
It’s like it’s relative…
So, in this case a moon timezone, and more generally a “space timekeeping framework” makes sense because time actually moves at a different speed on the moon, so epoch times wouldn’t actually stay in sync.
If the goal of “time” is to make it easier to reason about simultaneous things, then space makes that way more complicated.
It’s just tricky to condense that into a headline that conveys the point.
https://arxiv.org/abs/2402.11150
I suspect that won’t help. The reason the Moon needs a time zone is because of gravitational time dilation, time literally runs slower down here on Earth’s surface relative to the Moon’s surface. A computer on the Moon gains an extra 58.7 microseconds each Earth day, so if you’re programming something that’ll be running on Lunar time you’ll need to account for that.
The point of the lunar time zone is not to have a specific UTC offset like other timezones. The moon would have its own set of atomic clocks, and time could be coordinated with earth based on ratio instead of offset.
They’re not going to be maintaining literal atomic clocks on the Moon for this. They’ll apply a mathematical adjustment to UTC based on what the physics calculations say is happening. The details of that adjustment are what NASA has yet to develop. It could involve subtracting a “leap second” from lunar time at intervals, leap seconds are already used for keeping UTC in sync with the solar time so it’s an established process. Or maybe they’ll just let Lunar time continue drifting relative to Earth, in which case there’ll be a different “epoch” on each.
They probably actually will end up with atomic clocks on the moon, or at least in close lunar orbit. If the plan is to have something like gps on the moon, that’s a first step.
Don’t you dare, I have enough trouble reading 24 hour time.