A new study indicates Mercury has shrunk significantly more than previously believed. The planet may have lost up to 14 miles in diameter due to its interior cooling and contracting over billions of years. This shrinkage is considered substantial for a planet of Mercury's size. Researchers suggest that Mercury's rugged surface, altered by impact debris, might have concealed the full extent of this contraction. This discovery coincides with the approach of the BepiColombo spacecraft, a joint European and Japanese mission. BepiColombo is expected to orbit Mercury in November and then conduct a detailed survey. A laser instrument on BepiColombo is anticipated to verify the amount of shrinkage caused by internal cooling. The lead author of the study, Gaku Nishiyama, is involved in the BepiColombo mission. He believes the actual shrinkage could exceed current estimates derived from NASA's Messenger spacecraft data. Historically, only NASA's Mariner 10 had visited Mercury prior to these recent missions.