Mercury’s Quiet Collapse: New Data Shows the Solar System’s Smallest Planet Has Shrunk Far More Than Expected

A new study reveals Mercury has contracted up to 30% more than previously estimated, losing as much as 14.5 miles in diameter since formation. Surface roughness hid many tectonic features from earlier observations. The updated figures reshape models of the planet's interior and cooling history. BepiColombo's upcoming orbit will test the claims with higher resolution data.