Picture the deepest ocean trench you can imagine, nearly seven miles of dark water pressing down on cold, ancient rock.<\/p>\n
Now picture that rock sinking further<\/strong>, pulled down through the planet for hundreds of millions of years, until it comes to rest nearly 1,800 miles below your feet.<\/p>\n That is exactly what a team of geologists now believe happened, and the evidence they found at the very bottom of the world has given scientists a far richer picture<\/strong> of what the inside of Earth actually looks like.<\/p>\n The story starts not underground but on the surface of Antarctica, one of the most remote places on Earth.<\/p>\n A research team used the Transantarctic Mountains Northern Network (TAMNNET), a 15-station<\/strong> broadband seismic array deployed in Antarctica from 2012 to 2015, to map seismic waves from earthquakes over three years. <\/p>\n Every time an earthquake shook the Southern Hemisphere, those sensors picked up the ripples traveling through the planet.<\/p>\n The way those waves move and bounce reveals the composition of material deep inside Earth.<\/p>\n Think of it like tapping a wall and listening: a hollow wall sounds different from a solid one, and Earth’s interior behaves no differently<\/strong>.<\/p>\n What the team heard in three years of data was something nobody had expected to find at that depth.<\/p>\n At a depth of roughly 1,800 miles, Earth passes through one of its most dramatic boundaries.<\/p>\n The change in physical properties there is greater than the shift between solid rock at Earth’s surface and the air above it. <\/p>\n Right at that boundary, the sensors kept detecting patches of material that behaved strangely.<\/p>\n Because sound waves move slower in these areas, scientists call them ultralow velocity zones<\/strong>, or ULVZs.<\/p>\n For decades, scientists had observed isolated spots near the base of Earth’s mantle where traveling seismic waves slow significantly, and researchers now believe these features may be more widespread than previously thought. <\/p>\n The team found evidence of widespread, variable ULVZs along the core-mantle boundary beneath a largely unsampled portion of the Southern Hemisphere , and that finding alone was extraordinary enough before the next question hit.<\/p>\n The material in these zones is not just slow for the sound waves traveling through it.<\/p>\n These thin regions, about 5 to 50 kilometers thick, show strongly reduced seismic wave speeds and increased density compared to the rock around them. <\/p>\n That density is a fingerprint, and it points to something very specific.<\/p>\n The material also varies wildly in thickness from place to place, creating a landscape at the bottom of the mantle that is anything but flat.<\/p>\n As geophysicist Edward Garnero of Arizona State University put it, the material’s thickness varies from a few kilometers to tens of kilometers, suggesting mountains on the core, in some places five times taller<\/strong> than Mt. Everest. <\/p>\n The researchers believe these ULVZs are most likely oceanic crust that has been buried for millions of years , which raises an even stranger question about where that crust actually came from<\/strong>.<\/p>\n The highest-resolution map yet<\/a> of the geology beneath Earth’s Southern Hemisphere revealed something previously unknown: an ancient ocean floor that may wrap around the core.<\/p>\n This is the deep connection that stops scientists cold: the very same rock that once formed the bed of vanished seas<\/a>, cold dense oceanic crust dragged downward by tectonic plates, appears to have sunk all the way to the bottom of the planet.<\/p>\n Relatively cold subducting slabs continue the convection cycle as they descend down into the mantle, eventually reaching the core-mantle boundary after perhaps 100 million years, or more. <\/p>\n Simulations demonstrate that subducted materials from over the past 200 million years could be spread widely across the core-mantle boundary, not only beneath the Southern Hemisphere but also globally, advected within the lowermost mantle with lateral variations in accumulation. <\/p>\n Understanding exactly what sits beneath our feet is vital for studying everything from volcanic eruptions to variations in Earth’s magnetic field, which shields us from solar radiation.<\/p>\n The discovery that ancient ocean rock<\/a> may line the core-mantle boundary adds a new dimension to how scientists think about Earth’s deep interior and its long-term evolution.<\/p>\n Scientists are careful to say the ocean-floor interpretation is the most likely explanation, not the only one.<\/p>\n ULVZs are poorly understood, and their origins are debated, scientists have proposed two broad theories, though they are not mutually exclusive. <\/p>\n What is certain is that the core-mantle boundary is far richer and stranger than anyone assumed a generation ago.<\/p>\n As the University of Alabama’s Samantha Hansen put it, “Seismic investigations, such as ours, provide the highest resolution imaging of the interior structure of our planet, and we are finding that this structure is “vastly more complicated”<\/strong> than once thought.” <\/p>\n More Antarctic seismic stations are planned, and each new earthquake will send fresh data rippling through the core-mantle boundary beneath the Southern Hemisphere. <\/p>\n Piece by piece, the picture sharpens: the ancient ocean<\/strong> did not simply disappear when its floor was swallowed by the planet.<\/p>\n It went all the way down, and it is still there, wrapped around the heart of the world.<\/p>\n","protected":false},"excerpt":{"rendered":" Picture the deepest ocean trench you can imagine, nearly seven miles of dark water pressing down on cold, ancient rock. Now picture that rock sinking further, pulled down through the planet for hundreds of millions of years, until it comes to rest nearly 1,800 miles below your feet. That is exactly what a team of … Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":29754,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"15 station array","rank_math_title":"A 15-station array buried in Antarctic ice for 3 years mapped what sits 1,800 miles down, and the ancient thing that may wrap Earth's core was hiding at the bottom of a vanished ocean","rank_math_description":"Scientists used 15 Antarctic seismic stations to map Earth's core-mantle boundary and found ancient ocean floor may wrap entirely around the planet's core.","footnotes":""},"categories":[83],"tags":[],"class_list":["post-29755","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earth"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/29755","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=29755"}],"version-history":[{"count":0,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/29755\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/29754"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=29755"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=29755"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=29755"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}They buried sensors in Antarctic ice and listened to the planet shake<\/h2>\n
The zone where seismic waves slow to a crawl<\/h2>\n
Mountains taller than Everest, found where no eye will ever see<\/h2>\n
The ancient ocean floor that sank to the center of the world<\/h2>\n
What it means that the ocean goes all the way down<\/h2>\n