Why does the far side of the moon matter so much to us?

Thursday 3 January was a remarkable day in scientific exploration as China’s Chang-e 4 probe made a historic touchdown by being the first man-made device to land on the far side of the moon. It’s been a particularly hard feat to achieve, owing to the fact that beyond a certain point, earth cannot directly communicate with vehicles heading to the far side of the moon as the signals simply cannot reach. Instead, Chang-e 4 has had to communicate with its navigators by bouncing signals off another satellite in the earth’s orbit.

In confirming the event, Chinese state media said the landing “lifted the mysterious veil” from the far side of the Moon and “opened a new chapter in human lunar exploration”. Due to a rate at which it rotates on its axis, causing us to only ever see one of its faces.

Often referred to as ‘the dark side of the moon’ (despite the fact it receives plenty of light), the far side of the moon is something we still know very little about. However, from pictures taken by previous probes, what we do know is that it’s covered in vast craters, quite unlike the side we’re familiar with. In fact, the far side of the moon bares almost no resemblance to the near side, which may be due to conditions at the time of the moon’s origin.

Considering this, the far side of the moon is of great interest to humankind. It has been calculated that the craters found there are most likely due to a bombardment of asteroids, which have been estimated to have occurred around the same time period when life appeared on earth. This begs the question: was it the bombardment of asteroids that created conditions under which life could exist? Whilst our planet has lost almost all of its records of the conditions from that time, the far side of the moon could offer a fresh insight.

What makes this all the more interesting is at the time of the asteroid impact, the moon may not have been tidally locked to earth. Like many natural satellites, such as some of the moons of Jupiter and Saturn, over time gravity can cause a synchronization of rotation. But if the moon were not tidally locked to the earth at this time, what could be the reason for its two very different faces.

Landing on the far side of the moon offers numerous new possibilities for scientific research. To begin with, its position in the shadow of the earth means it is protected from earth’s interference, therefore the probe will be able to carry out radio wave observations at low frequencies that are not possible on earth due to our atmosphere.

Other fanciful equipment on the probe gives it the ability to dig deep into the surface of the moon to discover its layering and composition, monitor the solar winds in the area and even test for signs of lunar water. Perhaps most daringly, the team behind Chang-e 4 came up with the innovative idea of attempting to create a biosphere where they land, concealed in a sealed chamber. The lander arrived with six live species from the earth: yeast, potatoes, a type of flowering plant, cotton, rapeseed and fruit flies. Pictures received in mid-January showed that the cotton, potatoes and rapeseed were all growing well! Such results show us how life can thrive or die on this side of the moon, which may give insight into what would be possible were there to ever be a human settlement, scientific or other, on the moon.

 

Image credit: Pixabay

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