Look up at the bright moon, how small the bright moon is. But if you board a spaceship, put on a space suit, and embark on an epic moon trekking trip, guess how long it will take to circumnavigate the moon?
The answer depends on a variety of factors, including how fast you walk, how far you walk each day, and the detours you have to take to avoid dangerous terrain.
In total, circumnavigating the moon takes about a year or more. But in fact, in the process, there are still many challenges to overcome.
According to NASA, a total of 12 people have set foot on the lunar surface so far, all of whom were astronauts who participated in the Apollo mission between 1969 and 1972. The footage sent back to Earth tells us that in the moon's low-gravity environment— about one-sixth of Earth's gravity— walking (or more accurately jumping forward) is an extremely difficult (and fun) thing to do.
However, NASA's later research showed that humans could travel faster on the moon than the Apollo astronauts did. Theoretically, hiking around the moon could take longer than previously anticipated.
Pick up the pace
During the Apollo mission, astronauts jumped carelessly across the lunar surface at a speed of 2.2 kilometers per hour, according to NASA. The main reason for this slow pace is that they are wearing very bulky pressurized space suits. At that time, when people designed this space suit, they did not consider the flexibility of movement. But if the Moonwalkers put on lighter spacesuits, they might find it much easier to move, so they can speed up their walk.
In 2014, NASA published a study in the Journal of Experimental Biology that tested the speed at which humans walk and run under simulated lunar gravity. To do this, the team took eight participants (three of them astronauts) and asked them to walk on a treadmill on the DC-9 plane. During this time, the plane can simulate the gravity of the moon as it travels in a special parabolic trajectory on Earth, lasting about 20 seconds each time.
Experiments showed that participants could walk as fast as 5 kilometers per hour before running. Not only is this more than twice the walking speed of the Apollo astronauts, but it's also closer to our average maximum walking speed on Earth, which is 7.2 kilometers per hour.
Participants can walk so fast because they can swing their arms freely, just as we walk on Earth. This oscillation can produce a downward force, which in turn partially counteracts the absence of gravity. The Apollo astronauts, on the other hand, were unable to swing their arms because they were wearing bulky spacesuits, making them slow to move.
At this new maximum hypothetical velocity, we would only need 91 days to complete the lunar circumference, with a total length of 10,921 kilometers. In contrast, the Earth's equatorial circumference is 40,074 kilometers, and it takes about 334 days to complete the earth's week without interruption (for example, without eating, drinking or sleeping) at the same speed. But because of the oceans, we actually can't travel around the globe on foot.
Of course, no one can walk non-stop for 91 days in a row. So, a week of hiking around the moon will actually take longer.
Plan your route
Hiking on the moon also faces a variety of challenges. Aidan Cowley, a scientific adviser at the European Space Agency, said: "Logically, I think it's feasible. However, this task is so strange that not necessarily one person will actually try it. ”
One of the challenges of a lunar trek is to carry supplies such as water, food and oxygen.
Cowley said: "I think it may not be realistic to wrap these things with a back, because it is too heavy, even if the gravity on the moon is only one-sixth of that of the Earth." ”
So, Cowley says, you need a logistics car. The logistics car can then also double as a shelter. "Many space agencies are considering the possibility of using pressurized rovers, which can provide support while astronauts are on exploration missions, somewhat similar to mobile micro-bases," he said. At night you can stay in a logistics car, replenish your energy, and wait until the day to come out and continue walking. ”
Lunar adventurers, of course, also need a spacesuit, which is designed for maximum flexibility in movement. Cowley explained that the current space suit is still not considering much movement when designing and making, but there are also some institutions that are designing fitted space suits that allow the wearer's arms to swing freely and thus walk normally on the moon.
Then, the cratered terrain on the moon also means that finding a suitable route can be cumbersome, especially since some craters can be miles deep. Cowley said: "When you encounter a crater, you'd better take a detour, it's too dangerous." ”
Light and temperature are also factors to consider when planning your route. Cowley said: "Near the moon's equator, during the day, the temperature is about 100 degrees Celsius. By the evening, the temperature plummeted to minus 180 degrees Celsius. ”
Moon phases also mean that on some days, there may not be much sunlight all day and night, and at least half of the journey can only be carried out in total darkness. A specially designed spacesuit may be able to protect you in such extreme temperatures, and logistics vehicles can certainly provide protection. However, temperatures may also alter the state of the Moon's floating soil, a layer of fine gray soil that covers the moon's solid bedrock surface. Cowley said that changes in the state of floating soil will also affect the speed at which you walk.
In this photo taken in 1972, Apollo 17 lunar module pilot Harrison Schmidt is exploring the moon with an adjustable sampling spoon.
But perhaps even more dangerous is radiation. Unlike our Earth, there is no magnetic field on the Moon that blocks radiation. Cowley said: "If there was no major solar activity at that time, it might have been fine." But when a solar flare or coronal mass ejection occurs, you will be exposed to high radiation, which can seriously threaten your health. (According to NASA, both solar flares and coronal mass ejections release large amounts of energy particles and magnetic particles, but the types of particles released, how long the event lasts, and how radiation travels through space vary.) ）
Because your muscles and cardiovascular system need to move in a low-gravity environment, these tasks are also extremely demanding for endurance training. "You may need to send an astronaut with an ultramarathon fitness level to complete this task," Cowley said. ”
Finally, Cowley says, it can take a person three to four hours to walk at the fastest speed in a day. So, if a person walks at a rate of 5 kilometers per hour for four hours a day, assuming that his path is not too disturbed by craters, and that he also solves the challenges of temperature changes and radiation, it will still take him about 547 days, or nearly a year and a half, to circumnavigate the moon.
However, Cowley said, humans will not have until at least the late thirties or early 1940s to have the technology or equipment to accomplish this feat. "No space agency would support a mission like this. But maybe some whimsical billionaire will want to give it a try and put it into practice. (Yunlin)