{"id":20660,"date":"2024-08-28T08:10:24","date_gmt":"2024-08-28T02:40:24","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=20660"},"modified":"2025-10-13T11:20:55","modified_gmt":"2025-10-13T05:50:55","slug":"quasar","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/quasar\/","title":{"rendered":"What is a Quasar?"},"content":{"rendered":"<h2><strong>About Quasar:<\/strong><\/h2>\n<ul>\n<li>A quasar is an <strong>extremely active<\/strong> and <strong>luminous type of active galactic nucleus<\/strong> (<strong>AGN<\/strong>).\u00a0<\/li>\n<li><strong>An AGN is<\/strong> nothing more than <strong>a supermassive black hole<\/strong> that is <strong>active and feeding at<\/strong> the <strong>center of a galaxy<\/strong>.\u00a0<\/li>\n<li><strong>All quasars are AGNs<\/strong>, but <strong>not all AGNs are quasars.<\/strong><\/li>\n<li>Quasar is short for <strong>quasi-stellar radio source<\/strong>, because astronomers first discovered quasars in 1963 as objects that looked like stars but emitted radio waves.\u00a0<\/li>\n<li>Quasars are <strong>intense sources of X-rays as well as visible light<\/strong>. They are the <strong>most powerful type of X-ray source <\/strong>yet discovered.\u00a0<\/li>\n<li>They are among the <strong>most luminous, powerful, and vibrant objects<\/strong> known in the universe.<\/li>\n<li><strong>How are they formed?<\/strong>\n<ul>\n<li>Quasars are thought to form <strong>in regions<\/strong> of the universe where the<strong> large-scale density of matter is<\/strong> much <strong>higher than average.<\/strong><\/li>\n<li>An <strong>active galaxy<\/strong> is one in which the <strong>central supermassive black hole<\/strong> is <strong>consuming large amounts of matter<\/strong>.<\/li>\n<li>The <strong>in fall of matter into the black hole<\/strong> is so great that all the material can&#8217;t enter the black hole at the same time, so it <strong>forms a queueas<\/strong> a <strong>spiralling accretion disk.\u00a0<\/strong><\/li>\n<li>The <strong>matter<\/strong>\u2014in the <strong>form of huge clouds<\/strong>\u2014<strong>falls into the disk<\/strong>, with the inner parts of the cloud closer to the black hole orbiting faster than the outer parts (just like planets closer to the sun orbit faster than those farther away).\u00a0<\/li>\n<li>This creates a shear force that twists the clouds, causing them to bump into their neighbours as they move around the black hole at velocities ranging from 10% of the speed of light up to over 80%.<\/li>\n<li>This<strong> friction from fast-moving gas clouds generates heat<\/strong>, and the <strong>disk becomes so hot<\/strong>\u2014millions of degrees\u2014that it <strong>shines brightly.\u00a0<\/strong><\/li>\n<li><strong>Some of the material<\/strong> in the disk is <strong>also funnelled away<\/strong> from the black hole <strong>in a highly luminous, magnetically collimated jet.<\/strong><\/li>\n<li>The <strong>hot accretion disk and the jet combine to make<\/strong> the <strong>nucleus of<\/strong> the <strong>active galaxy shine so brightly<\/strong> that it can be seen far across the universe.<\/li>\n<\/ul>\n<\/li>\n<li>The <strong>brightest quasars<\/strong> can <strong>outshine all of the stars in the galaxies<\/strong> in which they reside, which <strong>makes them visible<\/strong> even at <strong>distances of billions of light-years<\/strong>.<\/li>\n<\/ul>\n<p><strong>Most quasars<\/strong> have been <strong>found billions of light-years away<\/strong>.<\/p>\n<hr \/>\n<h3><strong>Q1<\/strong>: What is a Black Hole?<\/h3>\n<p>A black hole is a region in space where the gravitational pull is so strong that nothing, not even light, can escape from it once it crosses a certain boundary called the event horizon. As a result, black holes are invisible to the naked eye and can only be detected indirectly by their effect on nearby matter and radiation.<\/p>\n<p><strong>Source: <\/strong><a href=\"https:\/\/www.ndtv.com\/science\/astronomers-discover-object-500-trillion-times-brighter-than-the-sun-6430389\" target=\"_blank\" rel=\"nofollow noopener\">Astronomers Discover Object 500 Trillion Times Brighter Than The Sun<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A quasar is an extremely active and luminous type of active galactic nucleus (AGN).<\/p>\n","protected":false},"author":5,"featured_media":20661,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":{"0":"post-20660","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-prelims-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/20660","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=20660"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/20660\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/20661"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=20660"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=20660"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=20660"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}