{"id":962435,"date":"2026-11-13T01:16:12","date_gmt":"2026-11-13T01:16:12","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/962435\/"},"modified":"2026-11-13T01:16:12","modified_gmt":"2026-11-13T01:16:12","slug":"stephen-hawkings-party-for-time-travelers-no-one-came","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/962435\/","title":{"rendered":"Stephen Hawking\u2019s Party for Time Travelers? No One Came"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Do three lines of math show that time travel is impossible? That\u2019s what a recent\u00a0<a href=\"https:\/\/arxiv.org\/abs\/2610.33706\" rel=\"nofollow noopener\" target=\"_blank\">paper<\/a>\u00a0uploaded to ArXiv says. <a href=\"https:\/\/www.sciencealert.com\/ivan\" rel=\"nofollow noopener\" target=\"_blank\">Ivan Farkas<\/a>\u00a0<a href=\"https:\/\/www.sciencealert.com\/just-3-lines-of-math-rule-out-time-travel-in-many-possible-universes-physicist-says\" rel=\"nofollow noopener\" target=\"_blank\">explains<\/a>\u00a0at\u00a0Science Alert:<\/p>\n<p class=\"wp-block-paragraph\">If our universe is one of a typical class,<\/p>\n<p class=\"wp-block-paragraph\">in such universes only forward movement is possible. As if driving down an endless one-way street with no service roads, turnarounds, or even an extended shoulder where one could pull over to enact a sneaky (illegal) U-turn.<\/p>\n<p class=\"wp-block-paragraph\">And, really, this is the basis of time travel, which has much different definitions depending on whether one is talking science or science fiction:<\/p>\n<p class=\"wp-block-paragraph\">\u201cPeople expect a result about time travel to need heavy machinery, energy conditions, quantum effects, maybe a singularity. It needs none of that. The whole content is bookkeeping about directions,\u201d [researcher Hongsheng] Zhang adds.<\/p>\n<p>\t\t\t\t\t\t\t\tDisplay &#8220;Stephen Hawking \u2013 Time Traveller&#8217;s Party&#8221; from YouTube\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/p>\n<p class=\"wp-block-paragraph\">Shortly before his retirement,\u00a0<a href=\"http:\/\/www.hawking.org.uk\/\" rel=\"nofollow noopener\" target=\"_blank\">Stephen Hawking<\/a>\u00a0(1942\u20132018) held\u00a0<a href=\"https:\/\/www.discovermagazine.com\/stephen-hawkings-time-travel-party-did-it-happen-how-would-we-know-45610\" rel=\"nofollow noopener\" target=\"_blank\">a party<\/a>\u00a0for time travelers, with the usual trappings, except for one thing. He did not send out the invitations until a day after the party. Needless to say, no one showed up holding one. Hawking felt that that ruled out time travel in this universe.<\/p>\n<p class=\"wp-block-paragraph\">Farkas adds that the new research shows us what we are up against if we want to reverse time:<\/p>\n<p class=\"wp-block-paragraph\">Finally, this offers a thought-and-math experiment of the type that has been influential throughout scientific history, allowing us to explore the abstruse principles that define our existence and possibilities.<\/p>\n<p class=\"wp-block-paragraph\">But the Universe, as always, has the final say, Zhang concludes:<\/p>\n<p class=\"wp-block-paragraph\">\u201cWhat it does not do is tell us whether nature permits any of this. That remains open, and it is the question I would most like to see answered.\u201d<\/p>\n<p class=\"wp-block-paragraph\">But we are a step closer: \u201cIf you want a time machine, you now know exactly what you must break.\u201d<\/p>\n<p class=\"wp-block-paragraph\">Maybe the time traveler must first find a different universe.\u00a0<\/p>\n<p class=\"wp-block-paragraph\">Cross-posted at Mind Matters News.<\/p>\n","protected":false},"excerpt":{"rendered":"Do three lines of math show that time travel is impossible? That\u2019s what a recent\u00a0paper\u00a0uploaded to ArXiv says.&hellip;\n","protected":false},"author":2,"featured_media":962436,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[64,63,292,128],"class_list":["post-962435","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-au","tag-australia","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/962435","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=962435"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/962435\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/962436"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=962435"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=962435"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=962435"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}