{"id":1815,"date":"2025-12-06T08:16:27","date_gmt":"2025-12-06T08:16:27","guid":{"rendered":"https:\/\/qpr.ca\/blogs\/physics\/?p=1815"},"modified":"2025-12-06T08:16:27","modified_gmt":"2025-12-06T08:16:27","slug":"what-optical-physics-principle-makes-the-earths-curvature-observable","status":"publish","type":"post","link":"https:\/\/qpr.ca\/blogs\/physics\/2025\/12\/06\/what-optical-physics-principle-makes-the-earths-curvature-observable\/","title":{"rendered":"What optical physics principle makes the Earth’s curvature observable?"},"content":{"rendered":"

The fact that a sharp horizon exists at a distance which increases noticeably over a fairly small increase in altitude should be convincing evidence of the Earth\u2019s curvature for anyone who thinks about it for a moment or two. And Domenico Barillari<\/a> is right to emphasize that the only evidence for the Earth\u2019s curvature that is visible in a static picture is the angle of depression of the horizon – which is NOT noticeable by eye (ie without using some scientific instrument) at any altitude that most of us will ever experience. But the only \u201coptical physics principle\u201d involved in either of those cases is the assumption that light travels in straight lines.<\/p>\n

However, although we can deduce<\/i> the Earth\u2019s curvature, we do not actually see<\/i> it in the form of a curved horizon. Pictures showing a horizon that curves down at the edges arise only when the camera\u2019s line of sight is angled downwards and would look the same if the visible part of the Earth was a perfectly flat disc. And again, the only \u201coptical physics principle\u201d involved is the assumption that light travels in straight lines.<\/p>\n

Source: (1001) Alan Cooper’s answer to When you see the Earth’s curvature from high altitude, what optical physics principle is at play that makes this phenomenon observable? – Quora<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

The fact that a sharp horizon exists at a distance which increases noticeably over a fairly small increase in altitude should be convincing evidence of the Earth\u2019s curvature for anyone who thinks about it for a moment or two. And Domenico Barillari is right to emphasize that the only evidence for the Earth\u2019s curvature that … Continue reading What optical physics principle makes the Earth’s curvature observable?<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"topics":[],"class_list":["post-1815","post","type-post","status-publish","format-standard","hentry","category-all"],"_links":{"self":[{"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/posts\/1815","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/comments?post=1815"}],"version-history":[{"count":1,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/posts\/1815\/revisions"}],"predecessor-version":[{"id":1817,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/posts\/1815\/revisions\/1817"}],"wp:attachment":[{"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/media?parent=1815"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/categories?post=1815"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/tags?post=1815"},{"taxonomy":"topics","embeddable":true,"href":"https:\/\/qpr.ca\/blogs\/physics\/wp-json\/wp\/v2\/topics?post=1815"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}