MESSENGER.
seventh mission of the Discovery program; orbital reconnaissance of the planet Mercury (2004–2015)
Mercury May Have Shrunk Up to 23 Kilometers
New research indicates Mercury has contracted 10% to 30% more than previously thought, shrinking about 12 miles (roughly 19 kilometers) in diameter since its formation, with surface debris from ancient impacts obscuring the planet’s shrinkage signs. The finding could imply a larger metal core or different core composition and temperature history, and future BepiColombo measurements are expected to help confirm the extent of Mercury’s cooling and contraction.
Science · 42 sources · Sep 13, 2026Read itThe journal
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About MESSENGER
MESSENGER was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for Mercury Surface, Space Environment, Geochemistry, and Ranging, and a reference to the messenger god Mercury from Roman mythology.
Everything about MESSENGER →- Website
- https://messenger.jhuapl.edu/, https://science.nasa.gov/mission/messenger/