{"id":208,"date":"2012-12-05T19:28:11","date_gmt":"2012-12-05T19:28:11","guid":{"rendered":"http:\/\/olofee.wordpress.com\/?p=208"},"modified":"2015-01-04T04:25:50","modified_gmt":"2015-01-04T04:25:50","slug":"our-nearest-neighbour-the-moon","status":"publish","type":"post","link":"http:\/\/malemuk.com\/olofee\/our-nearest-neighbour-the-moon\/","title":{"rendered":"Our nearest neighbour, the Moon"},"content":{"rendered":"

I recommend Pr. Carolin Crawfords Gresham lecture about the Moon<\/a>.<\/p>\n

I learnt:<\/p>\n

– the difference between the far side of the Moon, i.e. the side we never see, and the dark side of the Moon, i.e. the part of the side facing us that is not illuminated by the Sun.<\/p>\n

– that the angular velocity of the Moon is such that we always see the same part of its surface is that it is a position of equilibrium due to the tidal deformation of the Moon. Hard to explain in words, check Crawfords illustration at around 18’30”.<\/p>\n

– that the Moon has the same effect on the Earth, and is thus slowing down its angular velocity. 4 billion years ago, an Earth day lasted for about 6, and eventually, the Earth will be rotating in phase with the Moon. This means that there will be places on Earth were you never see the Moon.<\/p>\n

– due to the law of conservation of energy, the speed of the Moon is increasing as the angular velocity of the Earth is slowing down. This means, in turn, that the Moon is moving away from the Earth at a speed of about 3 cm \/ year. As it moves further away, it will eventually not be covering the whole Sun when there is a solar eclipse.<\/p>\n","protected":false},"excerpt":{"rendered":"

I recommend Pr. Carolin Crawfords Gresham lecture about the Moon. I learnt: – the difference between the far side of the Moon, i.e. the side we never see, and the dark side of the Moon, i.e. the part of the side facing us that is not illuminated by the Sun. – that the angular velocity […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[31],"tags":[],"class_list":["post-208","post","type-post","status-publish","format-standard","hentry","category-science"],"jetpack-related-posts":[{"id":2809,"url":"http:\/\/malemuk.com\/olofee\/living-in-truth\/","url_meta":{"origin":208,"position":0},"title":"Living in truth","date":"June 20, 2017","format":false,"excerpt":"https:\/\/www.youtube.com\/watch?v=ONzLgOHD6uw\u00a0at 57'14\" Chris Hedges: \"As Hannah Arendt wrote in the Origins of Totalitarianism, the only morally reliable people are not those who say this is wrong or this should not be done but those who say I can't. They know that, as Emmanuel Kant wrote, if justice perishes, human life\u2026","rel":"nofollow","context":"In \"Politics and Society\"","img":{"src":"","width":0,"height":0},"classes":[]},{"id":900,"url":"http:\/\/malemuk.com\/olofee\/significant-figures\/","url_meta":{"origin":208,"position":1},"title":"Significant figures","date":"December 31, 2015","format":false,"excerpt":"John Denker argues that it is insane to use significant figures. Instead one should follow these guidelines: Keep all the original data. Do not round off the original data. In the introductory class, the following \u201chouse rules\u201d apply: Basic 3-digit rule: For a number in scientific notation, the rule is\u2026","rel":"nofollow","context":"In \"Science\"","img":{"src":"","width":0,"height":0},"classes":[]},{"id":910,"url":"http:\/\/malemuk.com\/olofee\/emacs-tips\/","url_meta":{"origin":208,"position":2},"title":"Emacs tips","date":"December 31, 2015","format":false,"excerpt":"Essential shortcuts M-: META key (ALT on most keyboards) C-: CONTROL key C-x C-f : open file C-x b : switch to buffer C-x k : kill buffer C-s : search text forward C-r : search text backward C-+ \/ C-- : Zoom in\/out C-space: mark set (start of the\u2026","rel":"nofollow","context":"In \"Computer stuff\"","img":{"src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/posts\/208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/comments?post=208"}],"version-history":[{"count":1,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/posts\/208\/revisions"}],"predecessor-version":[{"id":454,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/posts\/208\/revisions\/454"}],"wp:attachment":[{"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/media?parent=208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/categories?post=208"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/malemuk.com\/olofee\/wp-json\/wp\/v2\/tags?post=208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}