{"id":87768,"date":"2025-06-01T06:53:49","date_gmt":"2025-06-01T06:53:49","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87768"},"modified":"2025-06-01T06:53:49","modified_gmt":"2025-06-01T06:53:49","slug":"twinkling-of-stars-is-due-to","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/","title":{"rendered":"Twinkling of stars is due to"},"content":{"rendered":"<p>Twinkling of stars is due to<\/p>\n<p>[amp_mcq option1=&#8221;particular frequencies of the starlight.&#8221; option2=&#8221;reflection of starlight from the oceanic surface.&#8221; option3=&#8221;atmospheric refraction of starlight.&#8221; option4=&#8221;magnetic field of Earth.&#8221; correct=&#8221;option3&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC NDA-1 &#8211; 2021<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-nda-1-2021.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-nda-1-2021\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe twinkling of stars is caused by the Earth&#8217;s atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\nStars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). Planets do not typically twinkle for this reason.<br \/>\n<\/section>\n<section id=\"pyq-additional_information\">\nRefraction is the bending of light as it passes from one medium to another or through a medium with varying properties. The refractive index of air changes with temperature and pressure, which vary throughout the atmosphere.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Twinkling of stars is due to [amp_mcq option1=&#8221;particular frequencies of the starlight.&#8221; option2=&#8221;reflection of starlight from the oceanic surface.&#8221; option3=&#8221;atmospheric refraction of starlight.&#8221; option4=&#8221;magnetic field of Earth.&#8221; correct=&#8221;option3&#8243;] This question was previously asked in UPSC NDA-1 &#8211; 2021 Download PDFAttempt Online The twinkling of stars is caused by the Earth&#8217;s atmosphere. As starlight travels through &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"Twinkling of stars is due to\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/#more-87768\">Detailed Solution<span class=\"screen-reader-text\">Twinkling of stars is due to<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1093],"tags":[1110,1153,1128],"class_list":["post-87768","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1110","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Twinkling of stars is due to<\/title>\n<meta name=\"description\" content=\"The twinkling of stars is caused by the Earth&#039;s atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction. Stars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). Planets do not typically twinkle for this reason.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Twinkling of stars is due to\" \/>\n<meta property=\"og:description\" content=\"The twinkling of stars is caused by the Earth&#039;s atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction. Stars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). Planets do not typically twinkle for this reason.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T06:53:49+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Twinkling of stars is due to","description":"The twinkling of stars is caused by the Earth's atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction. Stars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). Planets do not typically twinkle for this reason.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/","og_locale":"en_US","og_type":"article","og_title":"Twinkling of stars is due to","og_description":"The twinkling of stars is caused by the Earth's atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction. Stars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). Planets do not typically twinkle for this reason.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T06:53:49+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/","url":"https:\/\/exam.pscnotes.com\/mcq\/twinkling-of-stars-is-due-to\/","name":"Twinkling of stars is due to","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T06:53:49+00:00","dateModified":"2025-06-01T06:53:49+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The twinkling of stars is caused by the Earth's atmosphere. As starlight travels through the atmosphere, it passes through layers of air with varying densities and temperatures. This causes the light to be refracted (bent) multiple times. Since these layers are constantly moving and mixing due to atmospheric turbulence, the path of the starlight changes slightly from moment to moment. This results in fluctuations in the apparent brightness and position of the star, which we perceive as twinkling. This phenomenon is called atmospheric refraction. Stars appear as point sources of light because they are very distant. The light from a point source is more susceptible to the bending effects of atmospheric turbulence compared to the light from extended sources like planets (which appear as discs). 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