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 carsized 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.