China casts new light on ‘dark’ side of the moon
China’s historic landing may offer many insights into the universe — and could even get the US thinking about re-entering the space race
It’s a somewhat amusing thought, picturing the universe’s loneliest potato. A hearty, single spud gallantly attempting to grow on a dusty rock that is orbiting the loud green one — home to its friends — down below. It has nothing for company save some tomatoes, mouse-eared cress and silkworms. And a robot named after a rabbit.
Last week, the Chinese space probe Chang’e 4 made history with the first successful landing on the "dark side" of the moon. The car-sized spacecraft, named after the Chinese moon goddess, became the first vessel to land intact, obscured from our view.
This was mostly thanks to Magpie Bridge, a communications-relay satellite positioned more than 80,000km beyond the moon, which bounced transmissions between the Chang’e 4 and Chinese space stations.
Just 12 hours after the smooth landing in Aitken basin’s Von Kármán crater, Chang’e 4 — packed with a payload supplied by international partners in Sweden, Germany, the Netherlands and Saudi Arabia — dispatched the rover Yutu 2, named after the goddess’s pet jade rabbit, to begin tests and an eventual small-scale gardening scheme.
Chang’e 4 is part of a much bigger process: China has been systematically investigating the moon for the past 12 years. It started with Chang’e 1 (2007) and Chang’e 2 (2010) orbiting the natural satellite for scientific purposes. In 2013 Chang’e 3 performed China’s first investigatory landing on the moon’s "near" side.
The Chang’e 4 landing marks the second half of the exploration portion of China’s goal of manning an outpost on the moon’s south pole by 2030. The next step is set to take place in December, when Chang’e 5 will be tasked with transporting a 2kg lunar sample of basalt, mined 2m below the moon’s surface, back to Earth for further experimentation.
For now, Chang’e 4 has drawn fanfare from scientific communities around the world. It’s a very exciting prospect to finally be able to explore the far side of our closest neighbour. Forget what Pink Floyd may have led you to believe: the images transmitted by Yutu 2 prove that the far side is actually far lighter than the one we see.
The dark spots that have delighted the imagination with images of jade rabbits, cheese and old men are formed from encrusted magma that lines the craters left by meteor strikes. This is mostly because the moon’s crust is thought to be thinner on "our" side, making it easier for magma to emerge.
Why the discrepancy? We don’t know. But Briony Horgan, a planetary scientist at Purdue University in the US, is hopeful that Chang’e 4 will provide hints to the answer.
"The history of the very early solar system is locked up in the rocks of the far side," Horgan told The New York Times.
The only darkness that the far side of the moon can provide is that of radio silence, and that would be a big boost for scientists. We’re a noisy bunch, and our millions of radio satellites — providing us with spotty Cell C signal, mediocre pop tunes and Liverpool matches — have stood in the way of us better understanding our surroundings.
"We use radio wavelengths to probe everything from black holes in the local neighbourhood to distant galaxies, so a radio observatory on the far side could be a huge boon to astronomy," Horgan said. "The Chang’e 4 mission will be the first mission to test out this theory and to see just how much better the lunar far side is for radio observations than our observatories back on Earth."
It would be the first step towards improving the study of the primordial clouds of hydrogen gas that coalesced into the universe’s first stars, essentially allowing us to listen to the distant echo of the big bang. As it stands, despite our frequency interruption we have been able to construct the cosmic microwave background — a cosmic heat map of the universe as it appeared 370,000 years after the big bang. Imagine what we would achieve without all that noise?
For now, it’s likely that the only noise we will hear is the rumour of a new space race.
The US and China are already at loggerheads over trade. If they’ve gone so far as to arrest a Huawei CFO over the race for 5G, imagine what this landing will inspire, nearly 50 years after America’s "one small step" by Neil Armstrong, the first man on the moon.
It’s easy to assume that some US funding will find its way back to space agency Nasa after the government shutdown (once US President Donald Trump has stopped throwing a tantrum about that wall). But given that Nasa puts the cost of one moon mission at about $10bn— an amount that could fund the US’s national parks three times over — maybe Trump should get his House in order before competitiveness gets the better of him. Again.
Until then, we can simply enjoy the fact that it’s someone’s job to watch a robot try to grow silkworms and potatoes in space.