From Jim McHardy, Clydebank, West Dunbartonshire, UK
Instead of looking for evidence of tectonics on distant exoplanets, wouldn’t it be easier to look instead on Mercury? While not tidally locked, it experiences a very large temperature range of more than 600°C from its day to night side, and its day side remains in sunlight for many Earth months at a time. This compares with the suggestion that tidally locked exoplanet LHS 3844 b has a sunlit-to-dark-side temperature range of 770°C, and is expected to exhibit tectonic movement (7 December 2024, p 38).
Tectonic movement on Mercury, if it occurs, should be from equator to cooler poles. A very precise scan of Mercury’s surface compared with a future scan will show any movement. A lander that could detect “mercuryquakes” would also be an ideal way to investigate.
