Mercury is shrinking faster than we thought. What's going on inside of it?

New data collected by NASA’s MESSENGER spacecraft indicates that Mercury is contracting at an accelerated rate, significantly exceeding previous estimates. Detailed analysis of wrinkles observed across Mercury’s surface has provided crucial insights into this phenomenon. Scientists now believe the planet is diminishing in size approximately 14 millimeters per year. This shrinkage is primarily attributed to the interior cooling and contraction of Mercury’s metallic core. The rapid change suggests a more dynamic internal process than previously understood within our solar system's innermost planet.