In an image provided by the China National Space Administration, a closer look at a rock on the moon whose shape, seen from afar by China’s Yuta-2 rover, had prompted curiosity and discussion. The seemingly perfect geometric form of the “mystery hut” or “moon cube” was just a trick of angle, light and shadow. CNSA via The New York Times

Last November, China’s Yutu-2 lunar rover spotted something curious on the far side of the moon. The image was blurry, but it was unmistakable: The object looked like a cube sitting on the moon’s surface. Its shape looked too precise to be just a moon rock — perhaps something left by visiting aliens like the monolith in Arthur C. Clarke’s “2001: A Space Odyssey.”

China’s space authorities called it the “mystery hut.” Others called it the “moon cube.” Yutu-2 was sent for a closer look, and at the leisurely speed the rover is capable of traveling, it took weeks to get up close.

On Friday, Our Space, a Chinese language science channel affiliated with China National Space Administration, posted an update. There is no monolith, no secret base on the rim of a lunar crater. Close up, it turns out to be just a rock. The seemingly perfect geometric shape was just a trick of angle, light and shadow.

The report was noted earlier on Twitter by Andrew Jones, a journalist who follows the Chinese space program.

Although the mystery hut was not a hut at all, one of the rover’s remote drivers on Earth pointed out that the rock sort of resembled a rabbit and one of the stones in front of it looked a bit like a carrot. That’s fitting as the rover’s name means “Jade Rabbit.”

The rover has now driven just over 1,000 meters since it arrived three years ago on the moon’s far side, in Von Kármán crater, as part of the Chang’e-4 mission. It is the first mission to land on the far side.

Visual illusions are common in the history of space exploration, whether seen by astronomers peering through telescopes on Earth or robotic explorers on other worlds capturing images with cameras. In a parallel with the rabbitlike rock found by China’s rover, a NASA rover on Mars, Opportunity, spotted something that looked like bunny ears in 2004. Further analysis by engineers on Earth suggested it was insulation or other soft material that fell off the rover itself.

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