Mercury has lost significant mass over its 4.5 billion-year history, according to a new study. The planet’s interior has contracted due to thermal cooling, causing the surface to shrink and form faults.
In 1974, NASA’s Mariner 10 mission discovered large slope formations on Mercury, known as “scarps,” which are caused by faults beneath them. These scars indicate that the planet is contracting due to internal heat loss.
Scientists have estimated that Mercury has shrunk around 2-7 kilometers in the past, but a new study refines this estimate using an alternative method. By analyzing large fault lines and scaling up their effect to the entire population of faults, the team found that Mercury’s shrinkage ranges from 2.3 to 3.5 kilometers.
When accounting for additional global contraction, the estimated radial contraction is between 0.4-2.1 kilometers. Combining this with previous estimates yields a total radial contraction of 2.7-5.6 kilometers over Mercury’s lifetime.
The study suggests that its findings could replace previous estimates and provide valuable insights into thermal evolution modeling in the Solar System. As other planets also experience shrinkage, this research has broader implications for understanding celestial bodies’ internal changes.
Source: https://www.iflscience.com/mercury-is-shrinking-and-its-surface-may-have-just-revealed-by-how-much-80457