{"id":6805,"date":"2013-04-18T08:00:09","date_gmt":"2013-04-18T12:00:09","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=6805"},"modified":"2023-04-08T17:57:10","modified_gmt":"2023-04-08T21:57:10","slug":"time","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2013\/04\/time\/","title":{"rendered":"Time"},"content":{"rendered":"\n<p>The fourth dimension, at least in theory.\u00a0 We keep track of time in a linear way, each second marking a particular point that will happen only once and never be revisited.\u00a0 There will never be another 10:42:30.1 on April 17, 2013, for example.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"489\" height=\"500\" src=\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2023\/04\/World_line.jpg\" alt=\"\" class=\"wp-image-11391\" srcset=\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2023\/04\/World_line.jpg 489w, https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2023\/04\/World_line-147x150.jpg 147w\" sizes=\"auto, (max-width: 489px) 100vw, 489px\" \/><\/figure>\n\n\n\n<p>Of course, there are several ways to record the same time:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Coordinated Universal Time (UTC): This is the time at the prime meridian, 0\u00b0 Longitude.\u00a0 From there, time zones span out to +12 or -12 UTC, meeting again at the International Dateline.\u00a0 In military parlance, UTC is known as Zulu because it is in timezone Z.<\/li>\n\n\n\n<li>Local Time: In any given location, is determined when the sun is directly overhead (\u00b1 sidereal correction) at noon.<\/li>\n\n\n\n<li>Local Timezone:\u00a0 One of twenty-four arbitrary divisions where the sun may be directly overhead (\u00b1 sidereal correction) somewhere within the division at noon.<\/li>\n\n\n\n<li>Unix Timestamp:&nbsp; The number of seconds that has transpired since 0000, January 1, 1970.&nbsp; Unix time stamp 1366209730 equals 10:42:30, April 17, 2013.&nbsp; In hex looks like 516F0260.&nbsp; Used by all Unix\/Linux variants.<\/li>\n\n\n\n<li>GPS Time: UTC &#8211; LS (Leap Second) + 19 s.<\/li>\n\n\n\n<li>ISO 8601 date\/time: 2013-02-17T10:42Z<\/li>\n\n\n\n<li>Julian Date: A continuous count of days and fractions of such since noon Universal Time on January 1, 4713 BCE.\u00a0 April 17, 2013, 10:42:30.1 equals 2456399.946193<\/li>\n<\/ul>\n\n\n\n<p>One thing to note and mark your calendars: Unix (and variants) may have a problem on January 19, 2038, because of a 32-bit integer issue.\u00a0 This is known as Y2038, and a smart man would start planning now.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The fourth dimension, at least in theory.\u00a0 We keep track of time in a linear way, each second marking a particular point that will happen only once and never be revisited.\u00a0 There will never be another 10:42:30.1 on April 17, 2013, for example. Of course, there are several ways to record the same time: One &hellip; <a href=\"https:\/\/www.engineeringradio.us\/blog\/2013\/04\/time\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Time<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[271],"class_list":["post-6805","post","type-post","status-publish","format-standard","hentry","category-general","tag-oh-wtf"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6805","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=6805"}],"version-history":[{"count":13,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6805\/revisions"}],"predecessor-version":[{"id":11412,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6805\/revisions\/11412"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=6805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=6805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=6805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}