{"id":11886,"date":"2021-06-30T00:00:00","date_gmt":"2021-06-30T00:00:00","guid":{"rendered":"https:\/\/www.nextias.com\/current_affairs\/uncategorized\/30-06-2021\/discovery-of-a-new-source-of-gravitational-waves\/"},"modified":"2024-05-06T18:47:13","modified_gmt":"2024-05-06T13:17:13","slug":"discovery-of-a-new-source-of-gravitational-waves","status":"publish","type":"post","link":"https:\/\/www.nextias.com\/ca\/current-affairs\/30-06-2021\/discovery-of-a-new-source-of-gravitational-waves","title":{"rendered":"Discovery of a New Source of Gravitational Waves"},"content":{"rendered":"<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>In News<\/u><\/strong><\/span><\/span><\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Scientists have picked up the ripples in space-time caused by the death spiral of two celestial juggernauts \u2013 a neutron star and a black hole \u2013 for the first time.<\/span><\/span><\/span><\/p>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>About<\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">There is huge excitement among scientists with the <\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>first confirmed detection of a neutron star-black hole (NS-BH) collision<\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"> being reported.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Widely unequal mergers have very interesting effects that can be detected.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">This groundbreaking discovery of gravitational waves from a pair of NS-BH mergers.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Until now, the <\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>LIGO-Virgo collaboration (LVC) of gravitational waves<\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"> detectors has only been able to observe collisions between pairs of black holes or neutron stars.\u00a0<\/span><\/span><\/span><\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>How were the detections made<\/u><\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>?<\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">As the two compact and massive bodies orbit around each other, they come closer, and finally merge, due to the energy lost in the form of gravitational waves.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The Gravitational Waves signals are buried deep inside a lot of background noise.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The technique used here to detect the signal is called <\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>matched filtering<\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">. This was also used for the first discovery of gravitational waves.\u00a0<\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type: circle;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">In matched filtering, various expected gravitational waveforms predicted by Einstein\u2019s theory of relativity, are compared with the different chunks of data to produce a quantity that signifies how well the signal in the data (if any) matches with any one of the waveforms.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: circle;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>Whenever this match (in technical terms \u201csignal-to-noise ratio\u201d or SNR) is significant (larger than 8), an event is said to be detected.\u00a0<\/strong><\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Observing an event in multiple detectors separated by thousands of kilometres almost simultaneously gives scientists increased confidence that the signal is of astrophysical origin, which is the case for both events.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>Using Parameter Estimation tools, scientists find the probable masses, spins, distances, locations of these mergers from the data<\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Both of these events occurred 1 billion light-years away. As the gravitational waves also travel with the speed of light, <\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>this means that we observed mergers that happened ~1 billion years ago \u2014 well before life appeared on earth!<\/strong><\/span><\/span><\/span><\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>Significance<\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Inferring from data as to how often they merge will also give us clues about their origin and how they were formed.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">These observations help us understand the relative abundance of such binaries.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Neutron stars are the densest objects in the Universe, so these findings can also help us understand the behaviour of matter at extreme densities.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Neutron stars are also the most precise \u2018clocks\u2019 in the Universe if they emit extremely periodic pulses. The discovery of pulsars going around Black Holes could help scientists probe effects under extreme gravity.<\/span><\/span><\/span><\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>Blackhole<\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #1155cc;\"><strong><u>A blackhole<\/u><\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"> is a region in space where the pulling force of gravity is so strong that neither matter nor light can escape. This phenomenon occurs when a star is dying.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">For anything approaching a black hole, the point of no return is called the \u201cevent horizon\u201d and anything that comes within the event horizon will be consumed forever.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Since no light can escape from it, a black hole is invisible.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">However, advanced space telescopes can identify black holes by observing the behaviour of material and stars that are very close to black holes.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">This hot disk of material encircling a black hole shines bright and against this disk, a black hole appears to cast a shadow.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">This is how the photograph of the black hole was achieved.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">In 2019, NASA released the first-ever photograph of a black hole and its shadow, which was captured by an international network of radio telescopes called the Event Horizon Telescope (EHT).<\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type: circle;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The image shows the shadow of a supermassive black hole in the centre of Messier 87 (M87), an elliptical galaxy some 55 million light-years from Earth.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: circle;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">This black hole is 6.5 billion times the mass of the Sun.<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>Differences between Blackhole and Neutron Star<\/u><\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>:<\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">A neutron star has a surface and a <\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>Blackhole<\/strong><\/span><\/span><\/span><u> <\/u><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">does not.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">A neutron star is about 1.4-2 times the mass of the sun while the other black hole is much more massive.<\/span><\/span><\/span><\/li>\n<\/ul>\n<div>\n<table style=\"border-collapse: collapse; border: none; table-layout: fixed; width: 624px;\" cellspacing=\"0\">\n<tbody>\n<tr>\n<td style=\"background-color: #ffe599; vertical-align: top; border: 1px solid #000000;\">\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong><u>LIGO Scientific Collaboration<\/u><\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>:<\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The LIGO Scientific Collaboration (LSC) is a scientific collaboration of international physics institutes and research groups dedicated to the search for gravitational waves.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">Established in 1997<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">HQ: California Institute of Technology and Massachusetts Institute of Technology, United States<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">On 11 February 2016, the LIGO and Virgo collaborations announced that they succeeded in making the first direct gravitational wave observation on 14 September 2015.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The LSC is made up of around 1,400 scientists from 19 countries, and includes researchers from 11 UK universities including Strathclyde, Glasgow, Birmingham, Portsmouth and Cardiff.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type: disc;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">The UK\u2019s contribution to the collaborations is funded by the Science and Technology Facilities Council (STFC).<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p style=\"text-align: justify;\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\"><strong>Source<\/strong><\/span><\/span><\/span><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #000000;\">: <\/span><\/span><\/span><a style=\"text-decoration: none;\" href=\"https:\/\/indianexpress.com\/article\/cities\/pune\/ligo-finds-a-new-source-of-gravitational-waves-collisions-between-neutron-stars-black-holes-7381428\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-size: 11pt;\"><span style=\"font-family: Arial;\"><span style=\"color: #1155cc;\"><u>IE<\/u><\/span><\/span><\/span><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In News Scientists have picked up the ripples in space-time caused by the death spiral of two celestial juggernauts \u2013 a neutron star and a black hole \u2013 for the first time. About There is huge excitement among scientists with the first confirmed detection of a neutron star-black hole (NS-BH) collision being reported.\u00a0 Widely unequal [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":11887,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[21],"tags":[26,42,43],"class_list":["post-11886","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-current-affairs","tag-gs-3","tag-literature","tag-space"],"acf":[],"jetpack_featured_media_url":"https:\/\/wp-images.nextias.com\/cdn-cgi\/image\/format=auto\/ca\/uploads\/2023\/07\/5039844current-affairs.jpg","_links":{"self":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/11886","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/comments?post=11886"}],"version-history":[{"count":1,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/11886\/revisions"}],"predecessor-version":[{"id":24367,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/11886\/revisions\/24367"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media\/11887"}],"wp:attachment":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media?parent=11886"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/categories?post=11886"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/tags?post=11886"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}