1.0KMI - Nagoya Universityhttps://www.kmi.nagoya-u.ac.jp/engrich600338<blockquote class="wp-embedded-content" data-secret="IvryU0zV6e"><a href="https://www.kmi.nagoya-u.ac.jp/eng/seminar/1024/">Our Universe had (probably) an origin: Big Bang, cosmic singularities and quantum fluctuations</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.kmi.nagoya-u.ac.jp/eng/seminar/1024/embed/#?secret=IvryU0zV6e" width="600" height="338" title="“Our Universe had (probably) an origin: Big Bang, cosmic singularities and quantum fluctuations” — KMI - Nagoya University" data-secret="IvryU0zV6e" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script type="text/javascript"> /* <![CDATA[ */ /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); /* ]]> */ </script> I will briefly recall well-known evidence about the fact that, most probably, our Universe had an origin. I will devote some time to clarify the concept of Big Bang, namely: (i) what did Fred Hoyle mean when he said these two words for the very first time? (ii) what does it mean to the most rigorous mathematical cosmologists, e.g., the Big Bang singularity? Does it still make sense when one involves quantum effects? A theorem of Borde, Guth and Vilenkin, …