{"id":22092,"date":"2024-04-02T11:31:17","date_gmt":"2024-04-02T06:01:17","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=22092"},"modified":"2025-04-06T17:22:36","modified_gmt":"2025-04-06T11:52:36","slug":"leap-second","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/leap-second\/","title":{"rendered":"Leap Second"},"content":{"rendered":"<h2>About Leap Second<\/h2>\n<ul>\n<li>It is used as a measure to combat the long-term<strong> slowdown in the Earth\u2019s rotation<\/strong> which is caused by the constant melting and refreezing of ice caps.<\/li>\n<li>It is <strong>added every<\/strong> now and then to <strong>Coordinated Universal Time<\/strong> (UTC) in order to synchronize a clock worldwide with the Earth\u2019s ever <strong>slowing rotation.<\/strong><\/li>\n<li>The system of leap seconds was introduced in the early 1970s. So far, 27 positive leap seconds have been added.<\/li>\n<li>UTC consists of a time scale that combines the output of more than 300 highly precise Atomic clocks worldwide. Atomic clocks are very accurate and are stable within 1 second over a period of millions of years.<\/li>\n<li>On the other hand, the <strong>Astronomical Time<\/strong> known as <strong>Universal Time<\/strong> (UT1) refers to the Earth&#8217;s rotation around its own axis and determines the length of a day.<\/li>\n<li><strong>Reason for addition:<\/strong> The <strong>Earth&#8217;s rotation <\/strong>around its own <strong>axis is not regular<\/strong>, as sometimes it speeds up and sometimes it slows down, due to various factors including the moon\u2019s gravitational Earth-braking forces that often results in ocean tides.<\/li>\n<li>As a result, Astronomical Time (UT1) gradually falls out of synch with Atomic time (UTC), and as and when the difference between UTC and UT1 <strong>approaches 0.9 seconds, <\/strong>a \u201cLeap Second\u201d is added to UTC through Atomic clocks worldwide.<\/li>\n<li>A leap second is normally inserted either on June 30 or December 31.<\/li>\n<\/ul>\n<h2>What is Negative Leap second?<\/h2>\n<ul>\n<li>It is a second that is <strong>subtracted from our clocks<\/strong> to keep them in sync with the Earth&#8217;s rotation.<\/li>\n<li>Till date <strong>no negative leap second<\/strong> was introduced because, in the last few decades the Earth&#8217;s rotation has generally been a bit slow<\/li>\n<li>The <strong>International Earth Rotation and Reference Systems Service<\/strong> (IERS) monitors the Earth&#8217;s rotation, and takes decisions on when to add or subtract a leap second.<\/li>\n<li>Since Earth is <strong>spinning faster than<\/strong> usual recently, timekeepers had thought of using negative leap seconds for the first time.<\/li>\n<\/ul>\n<p>In other words, they thought of subtracting leap seconds from our clocks to synchronise them with Earth&#8217;s rotation.<\/p>\n<hr \/>\n<h3>Q1) What is Greenwich Mean Time (GMT)?<\/h3>\n<p>It is the mean (average) solar time at the Greenwich Meridian or Prime Meridian, 0 degrees longitude. The time displayed by the Shepherd Gate Clock at the Royal Observatory in Greenwich, London, is always GMT.<\/p>\n<p><strong>Source: <\/strong><a href=\"https:\/\/indianexpress.com\/article\/science\/melting-ice-negative-leap-second-postpone-9244686\/\" target=\"_blank\" rel=\"nofollow noopener\"><u>Melting ice sheets may postpone need for \u2018negative leap second<\/u><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Leap Second is used as a measure to combat the long-term slowdown in the Earth\u2019s rotation which is caused by the constant melting and refreezing of ice caps.<\/p>\n","protected":false},"author":5,"featured_media":22093,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":{"0":"post-22092","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-prelims-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/22092","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=22092"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/22092\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/22093"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=22092"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=22092"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=22092"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}