Over the span of 4.6 billion years, Mercury has quietly folded inward upon itself, its cooling interior drawing the planet's skin into long, buckled ridges that record a slow geological grief. A team at Hokkaido University has now measured this contraction with greater precision than before — nearly 12 kilometers of lost radius — by accounting for the scars of impact and eruption that had long concealed the full extent of the planet's shrinking. Their work reminds us that even the smallest worlds carry within them a deep history of transformation, and that what we cannot see may matter as much