{"id":1125,"date":"2012-07-06T08:47:00","date_gmt":"2012-07-06T14:47:00","guid":{"rendered":"http:\/\/www.ahwilderness.com\/?p=1125"},"modified":"2012-07-06T08:51:59","modified_gmt":"2012-07-06T14:51:59","slug":"a-day-late-but-still-interesting-variations-in-eccentricity","status":"publish","type":"post","link":"http:\/\/www.ahwilderness.com\/?p=1125","title":{"rendered":"A day late, but still interesting: variations in eccentricity"},"content":{"rendered":"<p><a href=\"http:\/\/www.usno.navy.mil\/USNO\/tours-events\/sky-this-week\/the-sky-this-week-2012-july-4-10\">The Sky This Week, 2012 July 4 &#8211; 10 \u00e2\u20ac\u201d Naval Oceanography Portal<\/a> <\/p>\n<blockquote><p>It\u00e2\u20ac\u2122s a bit hard to believe after our record heat wave of late, but the Earth is farthest from the Sun on the 4th at 11:32 EDT. At this time we will be 94,505,851 miles (152,092,424 kilometers) from Old Sol. Back on January 4 we were some 3,103,884 miles (4,995,217 kilometers) closer. As you can see, the variation in the aphelion and perihelion distances of the Earth are quite small compared to the overall mean distance to the Sun, but this quantity, known as the eccentricity of the Earth\u00e2\u20ac\u2122s orbit, slowly changes over time. Eccentricity is expressed as a ratio, and currently it is about 0.017. It can vary between 0.005 (nearly circular) to 0.06 (about a 12% ellipse) with two superposed cycles of some 100,000 and 400,000 years. These variations are primarily influenced by the gravity of the giant planet Jupiter, and at times of extreme eccentricity this can have a major effect on the planet\u00e2\u20ac\u2122s climate. Right now we\u00e2\u20ac\u2122re trending toward a more circular pattern, though, so we can\u00e2\u20ac\u2122t blame the current weather on Jupiter!<\/p><\/blockquote>\n<p><a href=\"http:\/\/www.usno.navy.mil\/USNO\/tours-events\/sky-this-week\/the-sky-this-week-2012-july-4-10\">The Sky This Week, 2012 July 4 &#8211; 10 \u00e2\u20ac\u201d Naval Oceanography Portal<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Sky This Week, 2012 July 4 &#8211; 10 \u00e2\u20ac\u201d Naval Oceanography Portal It\u00e2\u20ac\u2122s a bit hard to believe after our record heat wave of late, but the Earth is farthest from the Sun on the 4th at 11:32 EDT. At this time we will be 94,505,851 miles (152,092,424 kilometers) from Old Sol. Back on &hellip; <a href=\"http:\/\/www.ahwilderness.com\/?p=1125\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">A day late, but still interesting: variations in eccentricity<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"class_list":["post-1125","post","type-post","status-publish","format-standard","hentry","category-sky"],"_links":{"self":[{"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=\/wp\/v2\/posts\/1125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1125"}],"version-history":[{"count":0,"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=\/wp\/v2\/posts\/1125\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1125"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ahwilderness.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}