Pre-existing mineral deposits on the Moon (sinuous melt, above) have survived impacts powerful enough to melt rock. Not detectable in the crater image (inset), deposits are visible only in light at certain wavelengths. Credit: NASA and Deepak Dhingra
Large impacts on the Moon can form wide craters and turn surface rock liquid. Geophysicists once assumed that liquid rock would be homogenous when it cooled. Now researchers have found evidence that pre-existing mineralogy can survive impact melt.