The National Aeronautics and Space Administration (NASA) has officially begun work on a standard time for the Moon, and this time system, known as Coordinated Lunar Time (LTC), may be created by the end of 2026.
Source: Dima Zel
The reason for completing this work by the end of 2026 is that the American Artemis 3 mission is scheduled to send manned astronauts near the moon's south pole no earlier than 2026, when American astronauts and spacecraft will have access to the moon's time system.
So, the interesting question is, why did this moon landing need to create a special lunar standard time, and wouldn't it be nice that the previous Apollo missions to the moon did not have lunar standard time?
It is true that the Apollo moon landing did not use the time of the moon - the astronauts' watches at the time were synchronized with the time in Houston's time zone (where the rocket was launched), but the moon standard time was indeed necessary, even indispensable, mainly because time plays the most crucial role in modern technology, and the moon does not pass time in the same way as the Earth, which can lead to some work being done incorrectly or not being carried out.
图源：Pixabay / Christy Miller
Clocks on the moon go faster
Because the tides are locked, there is one side of the moon that is always facing us, so there may be some people who think that the moon will not have a change of day and night.
In fact, the moon is also rotating, and the sun will also shine on different areas of it, so the moon has day and night, just because the tide is locked, its rotation and revolution period are consistent, quite slow, and its day and night are about 2 weeks or so.
The Earth's 24-hour day is defined in terms of day and night, which doesn't seem to be very suitable for the Moon, which is one of the reasons for the establishment of the Moon's standard time, but not the main one.
The main reason is that the gravitational pull of the Moon is much smaller than that of the Earth, which causes time to travel faster there than on Earth, and if a spacecraft or astronaut on the Moon also quotes Earth Standard Time, then the watch there will travel about 58.7 microseconds faster every day (I will explain why this error is unacceptable), which is called time dilation.
Albert Einstein was one of the first scientists to discover this, initially believing that the speed of light is constant, and deriving the special theory of relativity from it.
Einstein's explanation of the invariance of the speed of light is that the speed of light is constant for any frame of reference, and no matter how fast you are, the speed of light does not change relative to you.
Image: Moving train A shoots arrows faster than forbidden B, but the speed of light is different, it's the same
Not only that, but if two people are moving at the same time, the speed of light is the same relative to both of them, no matter how much the speed difference between the two people is, for example, if you are moving at 99% of the speed of light, and the other person is moving at 1% of the speed of light, but the speed of light is the same relative to both of you.
It's hard to understand, it's very counter-intuitive, but Einstein's genius was to find an explanation, he thought that time changed during the movement.
Your time is not the same as the other person's time, and the faster you go, the slower the time passes, so you see the same speed of light as the other person sees the speed of light.
This is the special theory of relativity, which explains the time dilation of velocity, which has been verified in observational experiments.
Source: NASA
Because the space station is faster, the atomic clock carried on it records slower time, and scientists have also observed time dilation at speeds below 10 meters per second.
After the special theory of relativity, Einstein began to think about gravity again, and he also explained the nature of gravity in terms of the relative passage of time, which is the general theory of relativity.
We don't need to understand the specifics of general relativity, we just need to know that gravity also causes time dilation, and that the higher the gravitational force, the slower time passes.
This has also been observed in atomic clocks for gravitational time dilation on the Earth's surface with an altitude difference of only 1 meter, both in 2010 and in 2010 for the 10 meters per second velocity time dilation I mentioned earlier.
The gravitational pull of the Moon is not the same as that of the Earth, so time is naturally different, and time dilation can be calculated by formulas, and I found a ready-made answer here, the Moon will be 58.7 microseconds faster than the Earth every day - almost 0.02 seconds faster in a year.
Well, now there is another question, is it really necessary to set the time of the moon's independence for the 0.02 second error of the year?
Why is synchronization important?
If you're using your computer a lot and trying to troubleshoot some computer internet glitches, you may need to synchronize the time.
Personally, I have done this many times, especially in the era when the popularity of computers was not very high, every time the network could not be connected, usually just resynchronize the time of the computer, and you can access the Internet normally.
To be honest, I don't know why, and I've never looked into why I can go back online when I sync the time, but for the sake of this article, I've briefly explained why.
In fact, for the security of the Internet, to protect your personal privacy, and to protect your personal computer from third-party attacks when accessing the server, there is a so-called public key certificate system, which will give you a remote party's identity certificate every time you visit the website, thus improving the security factor.
The key to this public key certificate system is time, if the time of your computer is not synchronized, you will not be able to establish this certificate correctly, and it will naturally be inaccessible to the outside world.
In addition, in order to improve the security factor, many of our online transactions now have a concept of timestamps (in fact, this is now introduced in documents, events, images, etc.) - which means that the data has been completely existing at a certain point in time, so as to ensure that third parties cannot tamper with the data later.
In general, if you want to use Internet-related services on the moon, you must synchronize the time, otherwise the data will be wrong, and if you want to cancel the time-related settings, then the security cannot be guaranteed.
You may ask, is our time in Beijing the same as in other places?
Although, people in various regions of the world set their time according to their position on the globe – also known as time zones, all time zones around the globe are defined according to a single Coordinated Universal Time (UTC).
© 2017 Sunyixun
Coordinated Universal Time was developed by the International Bureau of Weights and Measures in Paris, France, and was created using a combination of atomic clocks from around the globe that input their own time into the Paris Central Laboratory to ensure that the clocks of each country are synchronized, which is the foundation of the global Internet.
However, the Internet and online transactions are not the only things that need to be time-dependent, in fact, more important is the global navigation system, which is also time-based, which is most important in lunar missions.
We know that navigation is achieved based on satellites, and satellites judge your position based on time, and satellite signals arrive a fraction of a second later than the current time on the ground, so it is possible to use the time difference to determine a person's position on the earth's surface with amazing accuracy.
In satellite navigation, to get an accurate position, you need to achieve a nanosecond error level, and as we mentioned earlier, the time error between the Moon and the Earth is 58.7 microseconds, and if the Coordinated Universal Time is also used on the Moon, then there will be a serious position deviation.
Source: NASA
The previous lunar missions were rough and single, without refined operation, but the 21st century lunar missions have obviously entered a stage of long-term work on the moon, so the standard time for the creation of the moon is necessary, and some scientists have even proposed the time to create Mars and other celestial bodies.
At last
However, there is a key question about lunar standard time, which is who will create it, or who will lead it.
In fact, not only NASA is doing this, ESA has also been doing it for a long time
Since everyone has their own priorities and visions, this complicates the creation of lunar standard time.
Original report: https://www.zmescience.com/science/the-moon-is-about-to-get-its-own-time-zone-heres-why-that-matters/