{"page":"<link rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/resources-572d6a42.css\" />\n<link rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/lp_boclips_stylesheets-f4d0de30.css\" media=\"all\" />\n<div data-title='Black Holes - Professor Joseph Silk' data-url='/boclips/videos/5cdb0b5bc8d53017a025aa92' data-video-url='/boclips/videos/5cdb0b5bc8d53017a025aa92' id='bo_player_modal'>\n<div class='boclips-resource-page modal-dialog panel-container'>\n<div class='react-notifications-root'></div>\n<div class='rp-header'>\n<div class='rp-type'>\n<i aria-hidden='true' class='fai fa-regular fa-circle-play'></i>\nVideo\n</div>\n<h1 class='rp-title' id='video-title'>\nBlack Holes - Professor Joseph Silk\n</h1>\n<div class='rp-actions'>\n<div class='mr-1'>\n<a class=\"btn btn-success\" data-posthog-event=\"Signup: LP Signup Activity\" data-posthog-location=\"body_link_boclips\" data-remote=\"true\" href=\"/subscription/new\"><span><span>Get Free Access</span><span class=\"\"> for 10 Days</span><span>!</span></span></a>\n</div>\n</div>\n</div>\n<div class='rp-body'>\n<div class='rp-info'>\n<div aria-label='Hide resource details' class='rp-hide-info' role='button' tabindex='0'>&times;</div>\n<i aria-label='Expand resource details' class='rp-expand-info fai fa-solid fa-up-right-and-down-left-from-center' role='button' tabindex='0'></i>\n<i aria-label='Compress resource details' class='rp-compress-info fai fa-solid fa-down-left-and-up-right-to-center' role='button' tabindex='0'></i>\n<div class='rp-rating'>\n<span class='resource-pool'>\n<span class='pool-label'>Publisher:</span>\n<span class='pool-name'>\n<span class='text'><a data-publisher-id=\"30356823\" href=\"/search?publisher_ids%5B%5D=30356823\">Gresham College</a></span>\n</span>\n</span>\n</div>\n<div class='rp-description'>\n<span class='short-description'>Supermassive black holes lurk in the very centres of galaxies. The Milky Way has a central black hole of four million solar masses. Today it is quiescent. But we have reason to believe that millions of years ago it was active. Traces of...</span>\n<span class='full-description hide'>Supermassive black holes lurk in the very centres of galaxies. The Milky Way has a central black hole of four million solar masses. Today it is quiescent. But we have reason to believe that millions of years ago it was <a href='http://www.gresham.ac.uk/lectures-and-events/black-holes' target='_blank' rel='nofollow'>active.</a> Traces of exploded debris are seen around our galactic centre that arose in a violent explosion some tens of millions of years ago. Most galaxies have massive central black holes, in some cases weighing billions of solar masses. These once were the sites of the most energetic phenomena in the universe, that astronomers recognise as quasars. I will describe feeding the monster within: the rise of the quasars, and how supermassive black holes formed long ago. These immensely luminous objects in the nuclei of galaxies were active when the universe was young. Current data suggests that supermassive black holes formed along with the first galaxies. The ultimate window on building massive black holes is gravity waves, and I will describe gravity wave experiments being planned to search for traces of the formation of such black holes. The transcript and downloadable versions of the lecture are available from the Gresham College <a href='http://www.gresham.ac.uk/lectures-and-events/black-holes' target='_blank' rel='nofollow'>website</a> Gresham College has been giving free public lectures since 1597. This tradition continues today with all of our five or so public lectures a week being made available for free download from our website. There are currently over 1,900 lectures free to access or download from the website. <a href='http://www.gresham.ac.uk' target='_blank' rel='nofollow'>Website</a> <a href='http://twitter.com/GreshamCollege' target='_blank' rel='nofollow'>Twitter</a> <a href='https://www.facebook.com/greshamcollege' target='_blank' rel='nofollow'>Facebook</a> <a href='http://www.instagram.com/greshamcollege' target='_blank' rel='nofollow'>Instagram</a></span>\n</div>\n<div class='action-container flex justify-between'>\n<button aria-expanded='false' aria-label='Read more description' class='rp-full-description' type='button'>\n<i class='fai fa-solid fa-align-left'></i>\n<span id='read_more'>Read More</span>\n</button>\n<div class='rp-report'>\n</div>\n</div>\n<div aria-labelledby='resource-details-heading' class='rp-info-section'>\n<h2 class='title' id='resource-details-heading'>Resource Details</h2>\n<div class='rp-resource-details clearfix'>\n<div class='detail'>\n<dl>\n<dt>Curator Rating</dt>\n<dd><span class=\"star-rating\" aria-label=\"4.0 out of 5 stars\" role=\"img\"><i class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"></i><i class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"></i><i class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"></i><i class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"></i><i class=\"fa-regular fa-star text-action\" aria-hidden=\"true\"></i></span></dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt class=\"educator-rating-title\">Educator Rating</dt><dd><div class=\"educator-rating-details\" data-path=\"/educator_ratings/rrp_data?resourceable_id=84729&amp;resourceable_type=Boclips%3A%3AVideoMetadata\"><span class=\"not-yet-rated\">Not yet Rated</span></div></dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Grade</dt><dd title=\"Grade\">10th - Higher Ed</dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Subjects</dt><dd><span><a href=\"/search?grade_ids%5B%5D=256&amp;grade_ids%5B%5D=257&amp;grade_ids%5B%5D=258&amp;grade_ids%5B%5D=259&amp;search_tab_id=1&amp;subject_ids%5B%5D=1216220\">All Subjects</a></span></dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Media Type</dt><dd><span><a href=\"/search?grade_ids%5B%5D=256&amp;grade_ids%5B%5D=257&amp;grade_ids%5B%5D=258&amp;grade_ids%5B%5D=259&amp;search_tab_id=2&amp;type_ids%5B%5D=4543647\">Instructional Videos</a></span></dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Source:</dt>\n<dd></dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Date</dt>\n<dd>2019</dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<i aria-hidden='true' class='fai fa-solid fa-language'></i>\n\n</dl>\n</div>\n<div class='detail'>\n<dl>\n<dt>Audiences</dt><dd><span><a href=\"/search?audience_ids%5B%5D=371079&amp;grade_ids%5B%5D=256&amp;grade_ids%5B%5D=257&amp;grade_ids%5B%5D=258&amp;grade_ids%5B%5D=259&amp;search_tab_id=1\">For Teacher Use</a></span></dd><dd class=\"text-muted\"><i class=\"fa-solid fa-lock mr5\"></i>2 more...</dd>\n</dl>\n</div>\n<div class='detail'>\n<dl>\n\n</dl>\n</div>\n</div>\n</div>\n<div aria-labelledby='educator-ratings-heading' class='rp-info-section'>\n<h2 class='title sr-only' id='educator-ratings-heading'>Educator Ratings</h2>\n<div id=\"educator-ratings-root\"></div><div id=\"all-educator-ratings-root\"></div><div id=\"educator-rating-form-root\"></div>\n</div>\n</div>\n<div class='rp-resource'>\n<div aria-label='Show resource details' class='rp-show-info' role='button' tabindex='0'>\n<i class='fai fa-solid fa-align-left'></i>\nShow resource details\n</div>\n<div aria-label='Video player' class='player' id='player-wrapper' role='region'>\n<div class='relative container mx-auto' id='lp-boclips-visitor-thumbnail'>\n<a class=\"block\" data-html=\"true\" data-placement=\"bottom\" data-trigger=\"click\" data-content=\"<div class=&quot;text-center py-2&quot;><a class=&quot;bold&quot; 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