The first thing you need to know is that time passes differently in different parts of the universe.

Gravity is not the same for all, just as there is no universal time common to all celestial bodies.

Astronomer Catherine Heymans told BBC Radio 4's Today programme, “Gravity is slightly weaker on the Moon and the clocks work differently” compared to Earth.

If those clocks were put on the moon, in 50 years, they would run one second faster.

Today, time on Earth is measured by hundreds of atomic clocks around our planet that record the changing energy state of atoms down to the nanosecond.

Kevin Goggins, NASA's communications and navigation representative, explained in that context, “When you go to another body, like the Moon or Mars, it makes sense that each one has its own heartbeat.”

The idea that time is relative comes from the theory of general relativity. Albert Einstein.

The assumption is that where gravity is stronger, time moves slower.

And as the mass of an object increases, the force of gravity becomes stronger.

For example, a container filled with a dense material such as granite rock has more mass and therefore a greater gravitational force than the same container filled with water.

In space, the Moon has less mass than Earth, so the Moon's gravitational pull is less than Earth's.

This explains why a person weighs less on the moon.

This weak gravity is the reason why there are famous images of the Apollo astronauts taking “one giant leap for mankind” on the surface of the moon.

Therefore, the greater the mass of a body, the slower its gravity and the slower time passes.

For example, on Jupiter, time passes more slowly than on Earth because of the greater gravity.

But on the Moon, because of its lower gravity, time passes faster.

The White House has asked the US space agency (NASA) to create a new time zone for the moon: it will be called “Coordinated Lunar Time”.

Their plan is to ensure that the new schedule will help ensure that national and private efforts to reach the moon do not follow separate paths.

However, it is not easy for all countries to agree on what this new time system should look like and which international organization will be responsible for coordinating it.

Currently, this work is carried out by the International Bureau of Weights and Measures for Earth Meteorology (BIPM).

From there the “Unified Universal Time” Used by the International Space Station.

But with the space race focused on the Moon, the definition of time used on the International Space Station may not be the most appropriate, experts say.

Another aspect countries must agree on is where the new deadline starts and how long it lasts.

Could rival countries like China, Russia or the US adopt the new “lunar time”?

This does not seem so simple amid the geopolitical tensions that underlie international relations.

The US wants to have its new lunar calendar ready by 2026, in time to send humans to the moon.

Artemis-3 will be the first mission to return to the lunar surface since Apollo 17 in 1972. It is planned to land at the lunar south pole, which is believed to contain large water ice in craters that never see daylight. the sun

A requirement to find and run this task Very accurate down to nanosecondsAny miscalculation could cause the spacecraft to enter the wrong orbit and collide.

If lunar time is not coordinated between countries planning to land on the satellite and private companies, new challenges may arise, reducing the chances of mission success and interfering with the transmission of data and communications between spacecraft. , Satellites and Earth.