Mercury Is Shrinking Much Faster Than Scientists Realized
A new analysis combining data from NASA’s MESSENGER mission and the European BepiColombo probe shows Mercury is shrinking far faster than scientists had previously believed, with global contraction leaving visible fault scarps across the planet’s surface. Researchers say the rate of cooling and contraction carries major implications for understanding the thermal evolution of small rocky planets, the durability of their magnetic fields, and the broader geological history of the inner solar system. The findings also raise fresh questions about how Mercury has retained a magnetic field despite being a small planet with a slowly solidifying inner core, a long-standing puzzle in comparative planetology.