Mercury, the closest planet to the Sun, may have contracted 10% to 30% more than previously estimated, according to a report of CNN which cited a new study. Researchers estimate that the planet’s radius may have decreased by about 7.2 miles (11.6 kilometers) as its interior cooled and contracted over billions of years.
The study points to wrinkles, cliffs and ridges across Mercury’s surface as evidence of this contraction. However, debris from asteroid and comet impacts may have obscured some of these geological features, causing previous studies to underestimate how much the planet has shrunk.
