{"id":134876,"date":"2024-12-08T23:19:52","date_gmt":"2024-12-08T16:19:52","guid":{"rendered":"https:\/\/hotvideos24.online\/?p=134876"},"modified":"2024-12-08T23:19:52","modified_gmt":"2024-12-08T16:19:52","slug":"quantum-censorship-could-hide-the-awful-truth-of-what-lies-inside-a-black-hole-sciencealert","status":"publish","type":"post","link":"https:\/\/hotvideos24.online\/?p=134876","title":{"rendered":"Quantum Censorship Could Hide The Awful Truth of What Lies Inside a Black Hole : ScienceAlert"},"content":{"rendered":"<p> <script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-3711241968723425\"\r\n     crossorigin=\"anonymous\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-layout-key=\"-fb+5w+4e-db+86\"\r\n     data-ad-client=\"ca-pub-3711241968723425\"\r\n     data-ad-slot=\"7910942971\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><br \/>\n<\/p>\n<div>\n<p>Albert Einstein&#8217;s theory of gravity, <a href=\"https:\/\/theconversation.com\/how-einsteins-general-theory-of-relativity-killed-off-common-sense-physics-50042\">general relativity<\/a>, is famously incomplete. As proven by physics Nobel laureate <a href=\"https:\/\/www.nobelprize.org\/prizes\/physics\/2020\/penrose\/facts\/\">Roger Penrose<\/a>, when matter collapses under its own gravitational pull, the result is a &#8220;singularity&#8221; \u2013 a point of infinite density or curvature.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>At a singularity, space, time and matter are crushed and stretched into nonexistence. The laws of physics as we know them suffer a complete breakdown.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>If we could observe singularities, our physical theories couldn&#8217;t be used to predict the future from the past. In other words, science would become an impossibility.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Penrose also realized nature may hold a remedy for this fate \u2013  <a href=\"https:\/\/www.sciencealert.com\/black-holes\" class=\"lar_link lar_link_outgoing\" data-linkid=\"73020\" data-postid=\"145809\" rel=\"nofollow noopener\" target=\"_self\">black holes<\/a>.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>A defining feature of a  <a href=\"https:\/\/www.sciencealert.com\/black-holes\" class=\"lar_link lar_link_outgoing\" data-linkid=\"73020\" data-postid=\"145809\" rel=\"nofollow noopener\" target=\"_self\">black hole<\/a> is its event horizon, a one-way membrane in space-time. Objects \u2013 including light \u2013 that cross the event horizon can never leave due to the black hole&#8217;s incredibly strong gravitational pull.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>In all the known mathematical descriptions of black holes, singularities are present in their core.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Penrose postulated that all the singularities of gravitational collapse are &#8220;clothed&#8221; by the event horizons of black holes \u2013 meaning <a href=\"https:\/\/personal.lse.ac.uk\/robert49\/PPB\/pdf\/Penrose1979a.pdf\">we could never observe one<\/a>. With the singularity inside the event horizon, physics in the rest of the universe is business as usual.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>This conjecture of Penrose, that there are no &#8220;naked&#8221; singularities, is called <a href=\"https:\/\/astronomy.swin.edu.au\/cosmos\/*\/Cosmic+Censorship+Conjecture\">cosmic censorship<\/a>.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>After half a century, it remains unproven and one of the most important open problems in mathematical physics. At the same time, finding examples of instances where the conjecture doesn&#8217;t hold up has proven equally difficult.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>In recent work, <a href=\"https:\/\/journals.aps.org\/prl\/abstract\/10.1103\/PhysRevLett.133.181501\">published in <em>Physical Review Letters<\/em><\/a>, we showed that quantum mechanics, which rules the microcosmos of particles and atoms, supports cosmic censorship.<\/p>\n<figure id=\"attachment_145813\" aria-describedby=\"caption-attachment-145813\" style=\"width: 1920px\" class=\"wp-caption alignnone\"><img decoding=\"async\" src=\"https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1.jpg\" alt=\"First black hole imaged\" width=\"1920\" height=\"1920\" class=\"wp-image-145813 size-full\" srcset=\"https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1.jpg 1920w, https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1-642x642.jpg 642w, https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1-415x415.jpg 415w, https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1-768x768.jpg 768w, https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1-1536x1536.jpg 1536w, https:\/\/www.sciencealert.com\/images\/2024\/12\/file-20241127-15-vt2pqj1-600x600.jpg 600w\" sizes=\"auto, (max-width: 1920px) 100vw, 1920px\" loading=\"lazy\"\/><figcaption id=\"caption-attachment-145813\" class=\"wp-caption-text\">First ever image of black hole. (Event Horizon Telescope\/Wiki Commons, CC BY-SA)<\/figcaption><\/figure>\n<h2>Black holes<\/h2>\n<p>Black holes are influenced by quantum mechanics to some extent, but such influence is normally ignored by physicists. For example, Penrose excluded these effects in his work, as did the theory that enabled scientists to measure ripples in space-time called <a href=\"https:\/\/theconversation.com\/explainer-what-are-gravitational-waves-53239\">gravitational waves<\/a> from black holes.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>When they are included, scientists call the black holes &#8220;quantum black holes&#8221;. These have long provided a further mystery, as we don&#8217;t know how Penrose&#8217;s conjecture works in the quantum realm.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>A model where both matter and space-time obey quantum mechanics is often considered the fundamental description of nature. This could be a <a href=\"https:\/\/theconversation.com\/great-mysteries-of-physics-do-we-really-need-a-theory-of-everything-203534\">&#8220;theory of everything&#8221;<\/a> or a theory of &#8220;quantum gravity&#8221;.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Despite tremendous effort, an experimentally verified theory of quantum gravity remains elusive.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>It is widely expected that any viable theory of quantum gravity should resolve the singularities present in the classical theory \u2013 potentially showing they are simply an artefact of an incomplete description. So it&#8217;s reasonable to expect quantum effects should not make the problem of whether we could ever observe a singularity worse.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>That&#8217;s because Penrose&#8217;s singularity theorem makes certain assumptions about the nature of matter, namely that the matter in the universe always has positive energy.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>However, such assumptions can be violated quantum mechanically \u2013 we know that negative energy can exist in the quantum realm in small amounts (called the <a href=\"https:\/\/physicsworld.com\/a\/the-casimir-effect-a-force-from-nothing\/\">Casimir effect<\/a>).<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Without a fully fledged theory of quantum gravity, it is difficult to address these questions. But progress can be made by considering &#8220;semi-classical&#8221; or &#8220;partially-quantum&#8221; gravity, where space-time obeys  <a href=\"https:\/\/www.sciencealert.com\/general-relativity\" class=\"lar_link lar_link_outgoing\" data-linkid=\"73026\" data-postid=\"145809\" rel=\"nofollow noopener\" target=\"_self\">general relativity<\/a> but matter is described with quantum mechanics.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Though the defining equations of semi-classical gravity are known, solving them is another story entirely. Compared to the classical case, our understanding of quantum black holes is much less complete.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>From what we do know of quantum black holes, they also develop singularities. But we expect a suitable generalisation of classical cosmic censorship, namely, quantum cosmic censorship, should exist in semi-classical gravity.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<h2>Developing quantum cosmic censorship<\/h2>\n<p>So far, there is not an established formulation of quantum cosmic censorship, though there are some clues.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>In some cases, a naked singularity can become modified by quantum effects to shroud the singularities; they become quantum dressed. That&#8217;s because quantum mechanics plays a role in the event horizon.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>The first such example <a href=\"https:\/\/iopscience.iop.org\/article\/10.1088\/1126-6708\/2002\/08\/043\">was presented<\/a> by physicists Roberto Emparan, Alessandro Fabbri and Nemanja Kaloper in 2002. Now, all known constructions of quantum black holes share this feature, suggesting a more rigorous formulation of quantum cosmic censorship exists.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Intimately linked to cosmic censorship is the <a href=\"https:\/\/iopscience.iop.org\/article\/10.1088\/1742-6596\/66\/1\/012004\/pdf\">Penrose inequality<\/a>. This is a mathematical relationship that, assuming cosmic censorship, says the mass or energy of of space-time is related to the area of black hole horizons contained within it.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Consequently, a violation of the Penrose inequality would strongly suggest a violation of cosmic censorship.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>A quantum Penrose inequality could therefore be used to rigorously formulate quantum cosmic censorship. One team of researchers <a href=\"https:\/\/journals.aps.org\/prl\/abstract\/10.1103\/PhysRevLett.123.241301\">proposed such an inequality<\/a> in 2019. While promising, their proposal is very difficult to test for quantum black holes in regimes where quantum effects are strong.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>In our work, we discovered a quantum Penrose inequality that applies to all known examples of quantum black holes, even in the presence of strong quantum effects.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>The quantum Penrose inequality limits the energy of space-time in terms of the total entropy \u2013 a statistical measure of a system&#8217;s disorder \u2013<br \/>of the black holes and quantum matter contained within it. This addition of quantum matter entropy ensures the quantum inequality is true even when the classical version breaks down (on quantum scales).<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>That the total energy of this system cannot be lower than the total entropy is also natural from the standpoint of  <a href=\"https:\/\/www.sciencealert.com\/thermodynamics\" class=\"lar_link lar_link_outgoing\" data-linkid=\"73052\" data-postid=\"145809\" rel=\"nofollow noopener\" target=\"_self\">thermodynamics<\/a>. To prevent a violation of the second law of thermodynamics \u2013 that the total entropy never decreases.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>When quantum matter is introduced, its entropy is added to the black hole&#8217;s, obeying a generalized second law. In other words, Penrose inequality can also be understood as bounds on entropy \u2013 exceed this bound, and the space-time develops naked singularities.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>On logical grounds, it was not obvious that all known quantum black holes would satisfy the same, universal inequality, but we showed they do.<\/p>\n<p><!-- START single\/mrec --><br \/>\n<!-- END single\/mrec --><\/p>\n<p>Our result is not a proof of a quantum Penrose inequality. But that such a result holds in the quantum domain as well as the classical one strengthens it.<\/p>\n<p>While space and time may end at singularities, quantum mechanics screen this fate from us.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img decoding=\"async\" src=\"https:\/\/counter.theconversation.com\/content\/244563\/count.gif?distributor=republish-lightbox-basic\" alt=\"The Conversation\" width=\"1\" height=\"1\" style=\"border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;\" referrerpolicy=\"no-referrer-when-downgrade\" loading=\"lazy\"\/><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https:\/\/theconversation.com\/republishing-guidelines -->\n<\/p>\n<p><span><a href=\"https:\/\/theconversation.com\/profiles\/andrew-svesko-2270145\"><em>Andrew Svesko<\/em><\/a><em>, Research Associate of Theoretical Physics, <a href=\"https:\/\/theconversation.com\/institutions\/kings-college-london-1196\">King&#8217;s College London<\/a>; <a href=\"https:\/\/theconversation.com\/profiles\/antonia-micol-frassino-2270759\">Antonia Micol Frassino<\/a>, Research fellow, <a href=\"https:\/\/theconversation.com\/institutions\/scuola-internazionale-superiore-di-studi-avanzati-4652\">Scuola Internazionale Superiore di Studi Avanzati<\/a>; <a href=\"https:\/\/theconversation.com\/profiles\/juan-f-pedraza-2270721\">Juan F. Pedraza<\/a>, Research Fellow at Instituto Fisica Teorica UAM\/CSIC, <a href=\"https:\/\/theconversation.com\/institutions\/universidad-autonoma-de-madrid-3521\">Universidad Aut\u00f3noma de Madrid<\/a>, and <a href=\"https:\/\/theconversation.com\/profiles\/robie-hennigar-2270148\">Robie Hennigar<\/a>, Willmore Fellow of Mathematical Physics, <a href=\"https:\/\/theconversation.com\/institutions\/durham-university-867\">Durham University<\/a><\/em><\/span><\/p>\n<p><strong>This article is republished from <a href=\"https:\/\/theconversation.com\">The Conversation<\/a> under a Creative Commons license. Read the <a href=\"https:\/\/theconversation.com\/naked-singularities-how-quantum-black-holes-explain-why-we-dont-see-the-end-of-space-and-time-244563\">original article<\/a>.<\/strong><\/p>\n<\/p><\/div>\n<p><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-3711241968723425\"\r\n     crossorigin=\"anonymous\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-layout-key=\"-fb+5w+4e-db+86\"\r\n     data-ad-client=\"ca-pub-3711241968723425\"\r\n     data-ad-slot=\"7910942971\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><br \/>\n<br \/><div data-type=\"_mgwidget\" data-widget-id=\"1660802\">\r\n<\/div>\r\n<script>(function(w,q){w[q]=w[q]||[];w[q].push([\"_mgc.load\"])})(window,\"_mgq\");\r\n<\/script>\r\n<br \/>\n<br \/><a href=\"https:\/\/www.sciencealert.com\/quantum-censorship-could-hide-the-awful-truth-of-what-lies-inside-a-black-hole\">Source link <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Albert Einstein&#8217;s theory of gravity, general relativity, is famously incomplete. As proven by physics Nobel laureate Roger Penrose, when matter collapses under its own gravitational pull, the result is a &hellip; <a href=\"https:\/\/hotvideos24.online\/?p=134876\" class=\"more-link\">Read More<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8628],"tags":[],"class_list":["post-134876","post","type-post","status-publish","format-standard","hentry","category-science","entry"],"_links":{"self":[{"href":"https:\/\/hotvideos24.online\/index.php?rest_route=\/wp\/v2\/posts\/134876","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hotvideos24.online\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hotvideos24.online\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hotvideos24.online\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/hotvideos24.online\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=134876"}],"version-history":[{"count":0,"href":"https:\/\/hotvideos24.online\/index.php?rest_route=\/wp\/v2\/posts\/134876\/revisions"}],"wp:attachment":[{"href":"https:\/\/hotvideos24.online\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=134876"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hotvideos24.online\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=134876"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hotvideos24.online\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=134876"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}