How do you tell the time on the moon?

Now, the US White House has tasked NASA to sort it out by 2026 when its next landing of people on the moon is scheduled to occur.

Four missions have already gone to the moon in 2024, with up to 10 more planned this year.

On average, there will be a mission to the moon every month for the next few years - and even more are likely to pop-up.

They are from many countries, and companies, and they all somewhat determine both how they keep time, and what time they operate on.

This is likely to create issues in the very near future.

While it may seem relatively simple, the way we keep time on Earth is based on thousands of years of change, work, and knowledge.

We have time zones, shifted from Greenwich Mean Time, so the beginning of the day occurs sunrise and the end of the day is at sunset.

This helps us conform to the rotation of the Earth, at 24 hours, so we have a somewhat normal day and night and our biological clocks work.

However, even how clocks on Earth work have changed.

For years, we had our clocks based on astronomical time - the motion of the stars in the sky. Observatories, like Mt Stromlo Observatory, kept a series of quartz clocks, that as certain stars moved overhead, these clocks were set to give us our official time.

The Earth's rotation is not perfect, and at fractions of a second, actually change.

While it may not matter to you waking up (other than making Mondays feel long) it is important for accurate navigation, operation of spacecraft, and even sending data via the internet.

Therefore now, we use atomic time.

Atomic time measures how often a certain atom vibrates to define a second, then we add those seconds up to an hour, and eventually a day.

Atomic time and astronomical time do not agree, and occasionally there is debate about a leap second. However, we have a system and it works.

Mars is also easy to work out. It is close enough to an Earth day, lasting for 24 hours and 37 minutes.

Martian time, and scientists working on Martian missions, have their clocks go slightly longer, calibrated to sunrise on Mars, and sunset on Mars.

But the moon is complicated.

A lunar day, the time it takes the moon to rotate on its axis, is the same as a lunar year, the time it takes to go around the Earth.

This means "daytime" lasts about 14 Earth days, and nighttime, 14 Earth days. Setting clocks so a "day" starts at sunrise and finish at sunset won't work.

Clocks themselves run slower on the moon than Earth, due to less gravity.

While it is only about 56 millionths of a second per day compared to Earth, that can quickly add up and precision measurements as well as computer may get out of sync, or stop working all together.

Now luckily, NASA is on it to solve this mess.