Japan's Hayabusa2 spacecraft brought samples of asteroid Ryugu to Earth in 2020, revealing that the asteroid may have been hit by a swarm of tiny space rocks around 1,000 years ago. The discovery was made due to a fine layer of sodium, just 10 nanometers thick, on the surface of Ryugu fragments. This build-up is unusual as volatile elements like sodium are usually depleted by solar winds. Researchers estimate that Ryugu's passage through a dense cloud of micrometeorites must have occurred around 1/10 years ago, an extremely recent event considering the asteroid's formation 4.6 billion years ago and its evolution as an asteroid near Earth demonstrates how near-Earth asteroids encounter swarms of meteoroids that can alter their surface properties.