The dark side of the Moon
China was the first nation to land a probe on the mysterious dark side of the Moon. The experiment could pave the way for future astronaut landings, and even human lunar settlements.
Wait, there is a dark side of the Moon?
Yes and no. The term that scientists prefer is “far side”. Essentially, from Earth we can only ever see one side of the Moon. This is because it takes just as long for the Moon to turn once on its own axis as it does to complete an orbit of the Earth.
However, the side we cannot see is not actually always in darkness. Just like Earth, the Moon orbits the Sun — so the regions that are in darkness are constantly changing.
Nevertheless, this “dark” side has often been the subject of wild conspiracy theories. Aliens, secret military bases and even a castle have been claimed to be hidden there. While these are all myths, the United States and Soviet Union both considered detonating nuclear bombs there during the Cold War.
And we have never been there before?
That’s right. Crew members of the NASA Apollo missions glimpsed it, but Neil Armstrong took his famous “small step” on the near side. In fact, the Chinese mission is only the second probe to be landed anywhere on the Moon since 1976.
What is the point of going there?
Plenty. The Chang’e 4 probe landed in a place called the South Pole-Aitken basin. Seven times deeper than the Grand Canyon, the basin cuts deep into the Moon’s surface. By using a ground penetrating radar, scientists discovered more about how the Moon was formed.
This process could shed light on one of the most dramatic events in the history of the solar system: the Late Heavy Bombardment. Between 700 million and one billion years ago, scientists believe that a huge number of objects were sent crashing through the solar system — some of which may have smashed into the far side of the Moon.
Scientists even think that this event could have coincided with when life first appeared on our own planet. “The late bombardment is fascinating because it may well have delivered a lot of the organics to Earth,” says scientist Matthew Genge.
Then there is water. Chang’e 4 scoured an area known to contain large reservoirs of water ice. How much? How deep is it buried? China has not told us yet.
If there is water, does that mean we could live there?
Possibly. Chang’e 4 is tracked radiation levels and took soil samples to see how viable long-term human habitation is.
One of its more precious pieces of cargo is a biosphere. This is a small container carrying six live species from Earth: cotton, rapeseed, potato, fruit fly, yeast and arabidopsis (a plant which could produce the first flower on the Moon). It is hoped that this experiment will determine if simple ecosystems can survive in sealed, low-gravity environments.
China, NASA and the European Space Agency have all declared an interest in building human settlements on the Moon. And NASA plans to start constructing an orbital base as soon as 2022 (it would orbit around the Moon, rather than be constructed on the surface).
Will man walk on the Moon again any time soon?
If all goes to plan. China will begin building its own space station, and it hopes to launch manned missions to the Moon between 2025 and 2030.
Some think this is a wake-up call to other space-faring nations. “The Chinese have a careful, strategic plan to supplant America as the world’s essential power,” claims political commentator and author Michael Pillsbury — “the way they have jumped ahead in the space race is just one part of that.”
- Should humans colonise the Moon?
- Watch the second video in Become An Expert — it explains how a Moon base could be built with today’s technology. Using what you have learnt, draw a design for your own Moon base. How would it work? How would people live, work, eat, sleep and relax? Present your design to the class.
- A lunar day (the time it takes for the Moon to rotate on its axis) lasts the equivalent of two weeks.
- The Apollo programme lasted from 1963 to 1972 — its mission: to land astronauts on the Moon. It achieved this for this first time in 1969, as well as in five subsequent missions.
- Neil Armstrong
- The first man to walk on the Moon. Upon taking his first step, he uttered these famous words: “That’s one small step for [a] man, one giant leap for mankind.”
- Since 1976
- China has another probe on the near side of the Moon: the Chang’e 3 which landed in 2013. Before that, the last probe to touchdown there was the Luna 24, launched by the Soviet Union in 1976.
- Water ice
- Liquid water cannot persist on the Moon, and water vapour is destroyed by sunlight. However, Lunar ice could be processed and used by human settlers.
- A type of energy that can be dangerous to humans.