{"id":655125,"date":"2026-10-23T20:30:10","date_gmt":"2026-10-23T20:30:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/655125\/"},"modified":"2026-10-23T20:30:10","modified_gmt":"2026-10-23T20:30:10","slug":"oct-23-1893-birth-of-ernest-opik","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/655125\/","title":{"rendered":"Oct. 23, 1893: Birth of Ernest Opik"},"content":{"rendered":"<p>\t\t\tBack to Article List\t\t<\/p>\n<p>\n\t\t\t\tToday in the history of astronomy, the first person to propose the Oort Cloud is born.\t\t\t<\/p>\n<p><\/p>\n<p>\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"563\" src=\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/10\/PIA22921_1280-e1761159842575.jpg\" class=\"attachment-large size-large wp-post-image\" alt=\"A horizontal diagram displays planets aligned along a white baseline extending from a glowing yellow Sun on the left into a black, star-filled space on the right. A large, curved orange bubble shaded with a blue border encloses the solar system region, with vertical text labels and numbers marking distances along the line. A small illustration of a spacecraft appears near the border, pointed toward a dense band of white speckles labeled across the dark background.\"\/><\/p>\n<p>\n\t\t\t\t\t\tNASA&#8217;s illustration here depicts the positioning of Voyager 2 relative to the Oort Cloud in 2018. Voyager 1 was in a similar location in 2013. Despite how close they appear, the scale of the solar system means it&#8217;ll take about 300 years for the Voyagers to reach the inner edge of the Oort Cloud. Credit: NASA\/JPL-Caltech\t\t\t\t\t<\/p>\n<p class=\"wp-block-paragraph\">Born Oct. 23, 1893, in Estonia, Ernest Opik was based at the Astronomical Observatory in Tartu from 1921-1944. It was there in the 1920s that he began to research meteors and comets, their frequencies, and their speeds. In 1932, he proposed a reservoir of long-period comets that formed a large cloud, orbiting the Sun at <a href=\"https:\/\/www.astronomy.com\/space-exploration\/will-voyager-1-and-2-be-damaged-passing-through-the-oort-cloud\/\" rel=\"nofollow noopener\" target=\"_blank\">the farthest reaches of the solar system<\/a>. Opik\u2019s theory was based on the fact that comets rapidly burn out once they swing into the inner solar system; therefore, he concluded, there must be a source out there somewhere to continue providing all the new comets we observe. In the 1950s, Jan Oort used cometary orbits to provide the mathematical evidence for this fresh-comet reserve. Although still a theoretical structure, this bubble or shell around our solar system is widely accepted as the explanation for long-period comets and is today known as <a href=\"https:\/\/www.astronomy.com\/science\/mysteries-of-the-oort-cloud-at-the-edge-of-our-solar-system\/\" rel=\"nofollow noopener\" target=\"_blank\">the Oort Cloud<\/a> \u2013 or, sometimes, as the Opik-Oort Cloud.<\/p>\n<p class=\"wp-block-paragraph\">Elisa Neckar is senior production editor of Astronomy magazine, and the editor of the Today in the History of Astronomy feature on <a href=\"http:\/\/astronomy.com\" rel=\"nofollow noopener\" target=\"_blank\">Astronomy.com<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"Back to Article List Today in the history of astronomy, the first person to propose the Oort Cloud&hellip;\n","protected":false},"author":2,"featured_media":655126,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[7809,85,46,195592,141,145,19197],"class_list":["post-655125","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-comets","tag-il","tag-israel","tag-outer-solar-system","tag-science","tag-space","tag-the-solar-system"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/655125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=655125"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/655125\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/655126"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=655125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=655125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=655125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}