{"id":11584,"date":"2015-10-16T15:50:18","date_gmt":"2015-10-16T19:50:18","guid":{"rendered":"http:\/\/hobbyspace.com\/Blog\/?p=11584"},"modified":"2015-10-16T15:50:18","modified_gmt":"2015-10-16T19:50:18","slug":"video-deciphering-the-reversals-and-excursions-of-the-earths-magnetic-field","status":"publish","type":"post","link":"https:\/\/hobbyspace.com\/Blog\/?p=11584","title":{"rendered":"Video: Deciphering the reversals and excursions of the Earth&#8217;s magnetic field"},"content":{"rendered":"<p>The <a href=\"https:\/\/en.wikipedia.org\/wiki\/Earth%27s_magnetic_field\" target=\"_blank\">earth&#8217;s magnetic field<\/a>\u00a0varies over time and even <a href=\"https:\/\/en.wikipedia.org\/wiki\/Geomagnetic_reversal\" target=\"_blank\">flips in polarity<\/a> periodically. Bruce Buffet of UC Berkeley talks in this SETI Institute seminar about efforts to understand how the earth&#8217;s interior causes\u00a0such variability :\u00a0<a href=\"http:\/\/www.seti.org\/weeky-lecture\/geomagnetic-reversals-and-excursions-origin-earths-magnetic-field\" target=\"_d\">Geomagnetic Reversals and excursions: The origin of Earth&#8217;s magnetic field &#8211;\u00a0SETI Institute<\/a><\/p>\n<p>&nbsp;<\/p>\n<p><span class=\"embed-youtube\" style=\"text-align:center; display: block;\"><iframe loading=\"lazy\" class=\"youtube-player\" width=\"1600\" height=\"900\" src=\"https:\/\/www.youtube.com\/embed\/oYHPVGuQAVw?version=3&#038;rel=1&#038;showsearch=0&#038;showinfo=1&#038;iv_load_policy=1&#038;fs=1&#038;hl=en&#038;autohide=2&#038;wmode=transparent\" allowfullscreen=\"true\" style=\"border:0;\" sandbox=\"allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox\"><\/iframe><\/span><\/p>\n<p>From the lecture announcement:<\/p>\n<p style=\"padding-left: 30px;\"><em>Palaeomagnetic observations offer important insights into the origin of Earth&#8217;s interior, but a detailed reconstruction of the underlying dynamics is not feasible. A practical alternative is to construct a stochastic model for the time evolution of the dipole field.<\/em><\/p>\n<p style=\"padding-left: 30px;\"><em>Slow changes in the field are described by a deterministic (drift) term, whereas short-time fluctuations are represented by a random (noise) term. Estimates for the drift and noise terms can be recovered from a time series of variations in the axial dipole moment over the past 2 million years. The results are used to predict a number of statistical properties of the palaeomagnetic field, including the average rates of magnetic reversals and excursions.<\/em><\/p>\n<p style=\"padding-left: 30px;\"><em>Dr. Buffet will explain how a physical interpretation of the stochastic models suggests that reversals and excursions are part of a continuum of time variations in Earth&#8217;s magnetic field, arising from convective fluctuations in the core. Relatively modest changes the amplitude of convective fluctuations can produce large changes in reversal rates, including the well-known occurrence of superchrons lasting longer than 10 million years.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The earth&#8217;s magnetic field\u00a0varies over time and even flips in polarity periodically. Bruce Buffet of UC Berkeley talks in this SETI Institute seminar about efforts to understand how the earth&#8217;s interior causes\u00a0such variability :\u00a0Geomagnetic Reversals and excursions: The origin of Earth&#8217;s magnetic field &#8211;\u00a0SETI Institute &nbsp; From the lecture announcement: Palaeomagnetic observations offer important insights &hellip; <a href=\"https:\/\/hobbyspace.com\/Blog\/?p=11584\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Video: Deciphering the reversals and excursions of the Earth&#8217;s magnetic field<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[9],"tags":[],"class_list":["post-11584","post","type-post","status-publish","format-standard","hentry","category-science-and-technology"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p34aWK-30Q","jetpack-related-posts":[{"id":10116,"url":"https:\/\/hobbyspace.com\/Blog\/?p=10116","url_meta":{"origin":11584,"position":0},"title":"Hubble study suggests large underground ocean on Jupiter&#8217;s moon Ganymede","author":"TopSpacer","date":"March 13, 2015","format":false,"excerpt":"The moons in the solar system continue to get more and more interesting. 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