{"id":193845,"date":"2024-12-12T15:11:31","date_gmt":"2024-12-12T15:11:31","guid":{"rendered":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/12\/12\/earths-inner-core-may-be-changing-shape\/"},"modified":"2024-12-12T15:11:31","modified_gmt":"2024-12-12T15:11:31","slug":"earths-inner-core-may-be-changing-shape","status":"publish","type":"post","link":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/12\/12\/earths-inner-core-may-be-changing-shape\/","title":{"rendered":"Earth\u2019s inner core may be changing shape"},"content":{"rendered":"<div style=\"text-align:center\"><img loading=\"lazy\" decoding=\"async\" width=\"763\" height=\"456\" src=\"https:\/\/i3.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/11\/survey_cta_footprint.jpg?resize=763,456&amp;ssl=1\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"Earth\u2019s inner core may be changing shape\" title=\"Earth\u2019s inner core may be changing shape\" \/><\/div> \r\n<br><div data-component=\"video-embed\">\n\t\t\t\t\n\n\n\n\n<p><strong>WASHINGTON, D.C. <\/strong>\u2014 Earth\u2019s inner core, a solid metal ball gyrating within the molten outer core, may be both slowing down and changing shape.<\/p>\n\n\n\n<p>Recent analyses of earthquake waves have suggested that around 15 years ago, the inner core\u2019s rotation may have slowed so much that it appeared to pause or reverse direction relative to the surface. But a new analysis suggests something more must be changing at Earth\u2019s center.<\/p>\n\n\n\n<p>The most probable explanation is that the inner core is not only rotating differently \u2014 <a href=\"https:\/\/agu.confex.com\/agu\/agu24\/meetingapp.cgi\/Paper\/1570592\" target=\"_blank\" rel=\"noopener\">its surface is probably also morphing<\/a>, geophysicist John Vidale of the University of Southern California in Los Angeles reported December 9 at a meeting of the American Geophysical Union. The finding could help resolve a long-standing debate over what is changing at the inner core.<\/p>\n\n\n<aside class=\"sn-conversion rich-text rich-text--with-sidebar\">\n<style><![CDATA[\n.email-conversion {\n  border: 1px solid #ffcccb;\n  color: white;\n  margin-top: 50px;\n  background-image: url(\"\/wp-content\/themes\/sciencenews\/client\/src\/images\/cta-module@2x.jpg\");\n  padding: 20px;\n  clear: both;\n}\n\n]]><\/style>\n\n\n\n<div class=\"rich-text embedded-conversion-content is-layout-flow wp-block-group-is-layout-flow\">\n<a href=\"https:\/\/docs.google.com\/forms\/d\/e\/1FAIpQLSf83OekELCTbhuYw3Iu-p8OWiE9-uE56ZFNbeTapotBaa1rIg\/viewform?usp=sf_link\">\n  <\/a><\/div><a href=\"https:\/\/docs.google.com\/forms\/d\/e\/1FAIpQLSf83OekELCTbhuYw3Iu-p8OWiE9-uE56ZFNbeTapotBaa1rIg\/viewform?usp=sf_link\">\n<\/a>\n\n<style><![CDATA[\n#dynamic-conversion {\n  border: 1px solid #ffcccb;\n  max-width: 100%;\n  height: auto;\n  clear: both;\n}\n]]><\/style>\n\n\n\n\n<\/aside>\n\n\n<p>No instrument can physically probe Earth\u2019s core. So, researchers study it using seismic waves from earthquakes. Scientists typically use quakes that occur in the South Sandwich Islands near Antarctica, which repose on the opposite side of the planet from instrument arrays in Alaska. The earthquake waves travel through the planet like sonar waves through water, with some passing through the inner core on their way to Alaska. Instruments there then record the waves as squiggly signatures called waveforms, which contain information about what the waves encountered on their journey through Earth.<\/p>\n\n\n\n<p>For robust detections of changes in the inner core, researchers compare similar-sized quakes that occurred in the same place but at different times. Such twin temblors, known as doublets, should generate the same waveforms if their journeys through Earth were identical. But researchers have observed that some doublets in the South Sandwich Islands generate different waveforms in Alaska, indicating that something in the inner core had changed between the times the two quakes in those doublets occurred.<\/p>\n\n\n\n<p>In 2023, geophysicists reported that the waveform differences stemmed from the inner core\u2019s rotation slowing down so much that it appeared to have <a href=\"https:\/\/www.sciencenews.org\/article\/earth-inner-core-reverse-rotation\">stopped moving \u2014 or even reversed \u2014<\/a> relative to the surface sometime around 2009 (<em>SN: 1\/23\/23<\/em>). Then, earlier this year, Vidale\u2019s team seemingly confirmed the reversal. They were able to match some waveforms <a href=\"https:\/\/www.sciencenews.org\/article\/earths-inner-core-has-weird-rotation\">before and after the turnaround<\/a>, identifying times when the inner core had reassumed a previous orientation toward the surface (<em>SN: 6\/25\/24<\/em>).<\/p>\n\n\n\n<p>For the new study, Vidale and colleagues analyzed about 200 pairs of earthquakes that occurred from 1991 to 2024. They examined matching waveform pairs from before and after the reversal, recorded at two separate receiver arrays located near Fairbanks, Alaska, and Yellowknife, Canada.<\/p>\n\n\n\n<p>Intriguingly, 10 doublets showed subtle differences in waveforms at Yellowknife that were not present in the Fairbanks waveforms. The team knew that the waves reaching these arrays, which are roughly 1,600 kilometers apart, take slightly different paths through Earth: Waves reaching Fairbanks penetrate deep into the inner core while those reaching Yellowknife graze its exterior.<\/p>\n\n\n\n<p>\u201cThe simplest explanation is deformation to the shallow inner core,\u201d Vidale says.<\/p>\n\n\n\n<p>It\u2019s possible that the entire geoid-shaped inner core is deforming, like a football being reshaped so its ends point in two new directions. Alternatively, he says, patches of the inner core\u2019s surface may be swelling or contracting. That would be like small bumps and dents forming on the metaphorical football. It\u2019s also possible that both processes are occurring. Such changes could be driven by the gravitational pull of the mantle \u2014 Earth\u2019s largest internal layer \u2014 or by material flowing in the outer core, Vidale says.<\/p>\n\n\n\n<p>This is not the first time researchers have reported that the inner core\u2019s surface changes over time. In 2006, geophysicist Lianxing Wen of Stony Brook University in New York reported that <a href=\"https:\/\/www.science.org\/doi\/10.1126\/science.1131692\" target=\"_blank\" rel=\"noopener\">patches of the region\u2019s surface<\/a> may rise or subside by hundreds of meters per decade, possibly due to material exiting the inner core as it cools. But unlike Vidale, Wen and colleagues like geophysicist Xin Zhang of the University of Science and Technology of China in Hefei maintain that <a href=\"https:\/\/agu.confex.com\/agu\/agu24\/meetingapp.cgi\/Paper\/1615701\" target=\"_blank\" rel=\"noopener\">the inner core does not rotate differently than Earth<\/a>. \u201cSurface changes can fully explain all the results,\u201d Zhang says.<\/p>\n\n\n\n<p>Geophysicist Xiaodong Song of Peking University in Beijing, who was one of the first to report that the <a href=\"https:\/\/www.nature.com\/articles\/382221a0\" target=\"_blank\" rel=\"noopener\">inner core rotates differently<\/a> from the rest of the planet, generally agrees with Vidale\u2019s findings. While the waveform differences are probably caused mostly by rotational changes, other processes such as surface changes may also be occurring, he says. \u201cIt\u2019s not either or.\u201d<\/p>\n\n\n\n<p>As for how all of this affects life on Earth, \u201cwe don\u2019t know that this is going to affect anything on the surface,\u201d Vidale says. \u201cBut we can\u2019t say for sure until we figure out what\u2019s happening.\u201d<\/p>\n\n\n\n\t\t\t<\/div>\r\n<br>\r\n<br><a href=\"https:\/\/www.sciencenews.org\/article\/inner-core-changing-shape-earth\">Source link <\/a>","protected":false},"excerpt":{"rendered":"<p>WASHINGTON, D.C. \u2014 Earth\u2019s inner core, a solid metal ball gyrating within the molten outer core, may be both slowing down and changing shape. Recent analyses of earthquake waves have suggested that around 15 years ago, the inner core\u2019s rotation may have slowed so much that it appeared to pause or reverse direction relative to [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":193846,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":"","fifu_image_url":"https:\/\/www.sciencenews.org\/wp-content\/uploads\/2024\/11\/survey_cta_footprint.jpg","fifu_image_alt":"","footnotes":""},"categories":[606],"tags":[4610,550,5043,1972],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/193845"}],"collection":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/comments?post=193845"}],"version-history":[{"count":1,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/193845\/revisions"}],"predecessor-version":[{"id":193847,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/193845\/revisions\/193847"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media\/193846"}],"wp:attachment":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media?parent=193845"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/categories?post=193845"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/tags?post=193845"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}