Hidden clues show Mercury shrank more than previously thought - USA Today
New research indicates that Mercury has shrunk more significantly than previously thought due to its cooling interior. Scientists believe that debris from asteroid and comet impacts has historically obscured the evidence of this contraction.
Why it matters
Understanding the geological history of Mercury provides critical insights into the formation and evolution of terrestrial planets in our solar system.
Hear this story New research suggests Mercury has shrunk more drastically than previously believed. The planet's cooling interior causes its surface to wrinkle and contract over time. Debris from asteroid and comet impacts has obscured evidence of the planet's shrinkage. A joint European and Japanese mission, BepiColombo, will arrive at Mercury in 2026 to study it further. Mercury may be the smallest planet in Earth's solar system , but evidence suggests it was not only much larger, but has shrunken far more drastically than scientists realized.
Conspicuous wrinkles on Mercury's surface have long indicated that the tiny world has gotten smaller and smaller over the eons.
Formed in the chaos of our solar system's early days , Mercury was shaped by violent forces that generated massive amounts of heat. As the years went by and that heat slowly escaped, Mercury has steadily been shrinking like a balloon in the cold.
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