{"id":460305,"date":"2025-12-20T15:58:12","date_gmt":"2025-12-20T15:58:12","guid":{"rendered":"https:\/\/www.europesays.com\/us\/460305\/"},"modified":"2025-12-20T15:58:12","modified_gmt":"2025-12-20T15:58:12","slug":"earths-rotation-froze-for-a-billion-years-scientists-finally-know-why","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/460305\/","title":{"rendered":"Earth\u2019s Rotation Froze for a Billion Years, Scientists Finally Know Why"},"content":{"rendered":"

For nearly a billion years, Earth\u2019s rotation stopped slowing down. Locked in a rare cosmic balance, the planet\u2019s day remained fixed at 19 hours<\/strong>, stalling the normal progression toward longer days. This plateau, uncovered through geological records, reveals a striking period of stability in Earth\u2019s deep past.<\/p>\n

Led by Ross Mitchell, a geophysicist at the Chinese Academy of Sciences<\/strong>, the research team compiled dozens of ancient day-length estimates from sedimentary rock layers<\/strong> covering the last 2.5 billion years<\/strong>. These patterns, studied using cyclostratigraphy<\/strong>, revealed Earth\u2019s rotation hasn\u2019t always slowed gradually. Instead, it entered a long-lasting equilibrium between opposing tidal forces.<\/p>\n

A Planetary Tug-of-war Froze Earth\u2019s Spin<\/p>\n

Between approximately two and one billion years ago<\/strong>, Earth\u2019s day length remained virtually unchanged<\/strong> at around 19 hours. According to Earth.com<\/a>, this stability was caused by a rare tidal resonance<\/strong>, a balancing act between lunar tides<\/strong>, which normally slow the E\u2019s rotation, and solar-induced atmospheric tides<\/strong>, which can speed it up.<\/p>\n

\n

\u201cEarth\u2019s day length appears to have stopped its long-term increase and flatlined at about 19 hours roughly between two to one billion years ago,\u201d Ross Mitchell <\/a>explained.<\/p>\n<\/blockquote>\n

While the Moon\u2019s gravitational <\/strong>pull generates tidal friction in the rocky world\u2019s oceans, slowly\u2014slowly robbing the planet of spin\u2014this effect was countered by daily heating from the Sun<\/strong>, which stirred pressure waves in the atmosphere. At 19 hours, these opposing forces matched almost exactly, halting our planet\u2019s gradual slowdown for nearly a billion years.<\/p>\n

Short Days, Slow Oxygen Rise<\/p>\n

This long period of stability had some surprising effects on Earth\u2019s atmosphere. At the time, most of the planet\u2019s oxygen came from cyanobacterial mats<\/strong>\u2014photosynthetic microbes spread across shallow sea floors. As stated in a study published in Nature Geoscience<\/a>, Judith Klatt<\/a><\/strong> and her team reveals that shorter days changed the way these microbes produced and used oxygen.<\/p>\n

Their work showed that when days were shorter than 16 hours<\/strong>, the mats actually used up more oxygen than they made<\/strong>. Even at 19 hours, the amount of oxygen they released wasn\u2019t much. As the same source reported, this steady day length likely kept oxygen levels low<\/strong> for hundreds of millions of years, which may have held back the rise of more complex life.<\/p>\n

\"TheThe relationship between Earth\u2019s day length and atmospheric oxygenation. Credit: Nature Geoscience<\/p>\n

Earth\u2019s Rotation Still Shifts, Just In Smaller Ways<\/p>\n

While the billion-year plateau is a thing of the past, Earth\u2019s rotation<\/a> hasn\u2019t stopped changing. Modern atomic clock measurements show that day length can drift slightly from year to year, influenced by winds, ocean currents, and deep-Earth processes<\/strong>.<\/p>\n

A previous research<\/a> by Liverpool University, analyzed the third planet from the Sun\u2019s spin from 1962 to 2012<\/strong>, subtracting atmospheric and oceanic influences to isolate deeper rotational forces. What remained revealed two key findings: a regular 5.9-year oscillation<\/strong> and abrupt changes coinciding with geomagnetic jerks<\/strong>, sudden shifts in our planet\u2019s magnetic field caused by movements in the liquid outer core<\/strong>. These observations suggest that, even today, the terrestrial planet<\/strong>\u2019s deep interior continues to subtly stretch and shrink our days.<\/p>\n","protected":false},"excerpt":{"rendered":"For nearly a billion years, Earth\u2019s rotation stopped slowing down. Locked in a rare cosmic balance, the planet\u2019s…\n","protected":false},"author":3,"featured_media":460306,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[159,783,67,132,68],"class_list":{"0":"post-460305","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-united-states","11":"tag-unitedstates","12":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115752725424430601","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/460305","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=460305"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/460305\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/460306"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=460305"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=460305"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=460305"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}