4179 Toutatis

4179 Toutatis is a stony near-Earth asteroid that makes repeated close passes of our planet, and on 13 December 2012 it became the first asteroid imaged up close by a Chinese spacecraft. Repurposed after its lunar mission, the Chang’e 2 probe swept within about 3.2 kilometres of Toutatis at nearly 11 kilometres per second, capturing this view of a dusty, reddish, peanut-shaped world.

Toutatis is an S-type asteroid — a body of silicate rock — measuring roughly 4.75 kilometres along its longest axis, with two distinct lobes that give it an elongated, peanut-like outline. Unlike most asteroids, it does not spin smoothly. It tumbles: one rotation around its long axis takes about 5.4 days while that axis itself wobbles every 7.4 days, combining into a chaotic, never-repeating motion likely shaped by sunlight over millions of years.

Discovered in 1989 and named after a Celtic god, Toutatis follows an Apollo orbit that crosses Earth’s path and is kept chaotic by resonances with Jupiter and Earth. That makes it a potentially hazardous object whose passes are tracked closely — and an inviting target that turned a recycled lunar probe into an asteroid explorer.