Little Mercury May Be Shrinking Faster Than Scientists Expected (apnews.com)
(Saturday September 12, 2026 @05:00AM (BeauHD)
from the planet-in-the-dryer dept.)
- Reference: 0185610566
- News link: https://science.slashdot.org/story/26/09/11/2050204/little-mercury-may-be-shrinking-faster-than-scientists-expected
- Source link: https://apnews.com/article/mercury-shrinking-planet-47b010ee65287f76565bc4859c7c09b3
A new study suggests Mercury [1]may have shrunk about 30% more than scientists previously thought , losing as much as 14 miles in diameter as its interior cooled and contracted over billions of years. "That's significant for a planet barely 3,000 miles (4,900 kilometers) across," reports the Associated Press. From the report:
> Mercury's rough surface, continually reshaped by debris hurled from impact craters, may have hidden the true extent of the loss, according to the researchers whose findings [2]appear in the journal Geophysical Research Letters . The news comes one week after a pair of European and Japanese spacecraft shed its cruising platform and advanced toward Mercury. [3]Known as BepiColombo , the linked craft are expected to enter orbit around Mercury in November before splitting up for a fuller survey.
>
> BepiColombo's laser instrument should confirm how much Mercury is withering as a result of internal cooling, said Gaku Nishiyama, the study's lead author who is taking part in the space mission. The shrinkage could be even more than his team is estimating based on measurements from NASA's Messenger spacecraft in the 2010s. Only one other spacecraft has ever visited Mercury, NASA's Mariner 10 in the 1970s.
[1] https://apnews.com/article/mercury-shrinking-planet-47b010ee65287f76565bc4859c7c09b3
[2] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026GL12406
[3] https://science.slashdot.org/story/25/01/11/0419232/spacecraft-buzzes-mercurys-north-pole-and-beams-back-stunning-photos
> Mercury's rough surface, continually reshaped by debris hurled from impact craters, may have hidden the true extent of the loss, according to the researchers whose findings [2]appear in the journal Geophysical Research Letters . The news comes one week after a pair of European and Japanese spacecraft shed its cruising platform and advanced toward Mercury. [3]Known as BepiColombo , the linked craft are expected to enter orbit around Mercury in November before splitting up for a fuller survey.
>
> BepiColombo's laser instrument should confirm how much Mercury is withering as a result of internal cooling, said Gaku Nishiyama, the study's lead author who is taking part in the space mission. The shrinkage could be even more than his team is estimating based on measurements from NASA's Messenger spacecraft in the 2010s. Only one other spacecraft has ever visited Mercury, NASA's Mariner 10 in the 1970s.
[1] https://apnews.com/article/mercury-shrinking-planet-47b010ee65287f76565bc4859c7c09b3
[2] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026GL12406
[3] https://science.slashdot.org/story/25/01/11/0419232/spacecraft-buzzes-mercurys-north-pole-and-beams-back-stunning-photos
14 miles in a few billion years? (Score:2)
Doesn't seem that much to me at all given how much iron can expand and contract per degrees C as it heats and cools. 14 miles out of 3000 is 0.5% which is nothing.