By Marcia DunnAP Aerospace Writer\u00a0 <\/p>\n
Sept. 13, 2026 3:16 PM PT <\/p>\n
CAPE CANAVERAL, Fla.\u00a0\u2014\u00a0A new study shows that little, wrinkly Mercury may be shrinking faster than expected, the cosmos\u2019 version of a grape shriveling into a raisin under the sun.<\/p>\n
Scientists from the German Aerospace Center\u2019s Institute of Space Research reported last week that Mercury\u2019s shrinkage may be 30% greater than previously believed \u2014 a loss in diameter of as much as 14 miles. That\u2019s significant for a planet barely 3,000 miles across. <\/p>\n
Mercury\u2019s 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 appear in the journal Geophysical Research Letters.<\/p>\n
The news comes days after a linked pair of European and Japanese spacecraft shed their cruising platform and advanced toward Mercury. Known as BepiColombo, the linked craft are expected to enter orbit around Mercury in November before splitting up for a fuller survey.<\/p>\n
BepiColombo\u2019s laser instrument should confirm how much Mercury is withering as a result of internal cooling, said Gaku Nishiyama, the study\u2019s lead author, who is taking part in the space mission. <\/p>\n
The shrinkage could be even more than his team is estimating based on measurements from NASA\u2019s Messenger spacecraft in the 2010s. Only one other spacecraft has ever visited Mercury, NASA\u2019s Mariner 10 in the 1970s.<\/p>\n
Our solar system\u2019s smallest and innermost planet has been shrinking ever since its formation 4.5 billion years ago. Its hot iron core \u2014 oversize for such a small world \u2014 cools and contracts along with the mantle and crust, tightening the surface like a girdle to fit its new slimmer self.<\/p>\n
Nishiyama and his team compared maps showing faults and other geologic signs of contraction at Mercury with newer maps highlighting surface roughness. They discovered that the roughest patches exhibited fewer shrinkage wrinkles. The missing wrinkles could be buried under impact debris, they said.<\/p>\n
After accounting for these obscured regions, the researchers provided a fresh take on Mercury\u2019s shrinkage that could shed light on other contracting worlds, said Nishiyama, who is affiliated with Hokkaido University in Japan.<\/p>\n
\u201cWe are quite excited,\u201d he said in an email, adding that it feels like \u201cwe are approaching the reality of Mercury\u2019s evolution.\u201d<\/p>\n
Dunn writes for the Associated Press. <\/p>\n","protected":false},"excerpt":{"rendered":"By Marcia DunnAP Aerospace Writer\u00a0 Sept. 13, 2026 3:16 PM PT CAPE CANAVERAL, Fla.\u00a0\u2014\u00a0A new study shows that…\n","protected":false},"author":2,"featured_media":894820,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[305828,49,48,309939,12395,7964,9990,8456,41981,307,2874,9593,309941,66,36724,309940,795,2341],"class_list":["post-894819","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-bepicolombo","tag-ca","tag-canada","tag-gaku-nishiyama","tag-last-week","tag-loss","tag-map","tag-mercury","tag-mile","tag-nasa","tag-planet","tag-researcher","tag-rough-surface","tag-science","tag-scientist","tag-shrinkage","tag-study","tag-team"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/894819","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=894819"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/894819\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/894820"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=894819"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=894819"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=894819"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}