The team revealed that the sample surfaces contain small ‘melt splashes,’ ranging in size from 5 to 20 micrometers. These melt splashes were created when micrometeoroids of cometary dust bombarded Ryugu. The chemical compositions of the melt splashes suggest that Ryugu’s hydrous silicates mixed with cometary dust. The mixing and melting of Ryugu’s surface materials and cometary dust during impact-induced heating and rapid cooling formed the melt splashes. The voids correspond to the water vapor released from the Ryugu’s hydrous silicates and subsequently captured in the melt splashes.