A recent study published in AGU Advances provides new insights into how much Mercury has shrunk since its formation 4.5 billion years ago. Researchers employed a novel method for estimating the planet’s shrinkage, which offers a more accurate understanding of Mercury’s cooling process.
According to the study, Mercury’s core has cooled and contracted over billions of years, leading to the formation of thrust faults on its surface. These faults are similar to cracks that form in baked goods as they cool and contract. The researchers used a method that focused on the largest fault within a dataset and scaled that shrinkage to estimate the total contraction.
Their findings reveal that Mercury’s radius has shrunk by approximately 2 to 3.5 kilometers, with an estimated range of 2.7 to 5.6 kilometers. This new methodology provides a clearer understanding of Mercury’s thermal history and offers valuable insights into the planet’s internal processes.
The accurate estimates of Mercury’s shrinkage are crucial for understanding the planet’s cooling history. By knowing how much the planet’s radius has changed over time, scientists can better model the cooling of its core and its internal heat flow. This helps to paint a picture of how Mercury, a planet with no atmosphere and extreme temperature variations, has evolved.
The study’s findings refine our understanding of Mercury’s past thermal environment and provide a more precise measure of shrinkage, paving the way for more detailed and accurate models of Mercury’s geological history.
Source: https://dailygalaxy.com/2025/08/the-mystery-of-mercurys-shrinking-revealed