Study Finds Mercury's Shrinkage May Be 30% Greater Than Previously Estimated
Research by the German Aerospace Center suggests Mercury could be losing up to 14 miles in diameter, a rate 30% higher than earlier estimates, and upcoming BepiColombo measurements aim to verify the finding.
Scientists from the German Aerospace Center's Institute of Space Research have reported that Mercury may be shrinking faster than earlier models indicated, with a possible loss of as much as 14 miles in diameter, roughly 30% greater than previous estimates. The findings, published in Geophysical Research Letters, attribute the contraction to the cooling of the planet's oversized iron core, which causes the mantle and crust to contract and the surface to compress.
The researchers note that Mercury's heavily cratered surface can obscure precise measurements of its size change. The upcoming BepiColombo mission, a joint European-Japanese effort, is scheduled to enter Mercury's orbit in November. Its onboard laser instrument is expected to provide direct observations of the planet's current dimensions, which should confirm the rate of shrinkage reported in the study.
"BepiColombo's laser instrument should confirm how much Mercury is withering as a result of internal cooling," said Gaku Nishiyama, lead author of the study and a participant in the mission.
Mercury has been gradually contracting since its formation about 4.5 billion years ago as its interior cools, a process that continues to reshape the planet's surface.