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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>>…</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <b>On Behalf Of </b>Tomaz Kristan<br><b>Subject:</b> Re: [ExI] Where are they? was Re: 2^57885161-1<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal style='margin-bottom:12.0pt'>><span style='color:#1F497D'>>…</span> I am struck with this picture<span style='color:#1F497D'> {NASA deep space image}</span> of one tiny<br>patch of sky containing at least several hundred galaxies, each with<br>billions of stars. I just can't get my head around the notion that<br>intelligence came together only once with all that out there. There must be<br>something fundamental we are missing or still haven't discovered.<o:p></o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='color:#1F497D'>>…</span>It is just not enough of galaxies that a coin could land 200 times head up, if one was tossed every second on every plane.<o:p></o:p></p></div><p class=MsoNormal><span style='color:#1F497D'>>…</span>Or just about once. The same holds for life.<span style='color:#1F497D'> Tomaz<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Well now let’s look at that Tomaz. If coins are tossed 2^200 times then the probability of 200 consecutive heads coming up at least once in that sequence is about 63%. 2^200 is about 1^60, so let’s take the generally accepted estimate of the number of stars in the observable universe at about 100 billion galaxies times about 100 billion stars per galaxy, and ignore for the moment that the estimate is generally higher in recent years. Then the number of stars is about E22, and we can imagine that a fairly typical star has about between 1 and 10 orbiting objects on average, keeping in mind that our sun has about 50 that meet this description because we include larger satellites but not all those asteroids. But assume about 10 per star for conservative measure, so about 1E23 orbiting objects, and now using your one coin per second, and accepting the estimated 14 billion year life of the universe and leave some time for heavy elements to be cooked up in stars and subsequently being supernova-ed into the cosmos to form accretion discs and planets, so about 1E33 planet-years which is about 3E40 planet-seconds since the observable universe was about 4 billion years along from the big bang. So if we want to have that .63 probability, we need not one coin toss per planet second, but rather about 3E19 coin tosses per planet-second. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>OK then, what if we get one coin toss per square meter of planet surface, rather than one coin toss per planet second? I see this as perfectly reasonable; if you are a bit of goo trying to become a lifeform, you are small, so a square meter is a lotta area. The surface area of our typical planet is about 4pi(6300000)^2 or about 5e14 m2, so we have about 1.5E55, which still leaves us over 4 orders of magnitude short, so let us recognize and press a little harder on the previous notion that to a bit of organic goo, a square meter is a nice sized playground, and recognize that a square millimeter is a pretty good sized backyard too. If you do that, we get about 1.5E61 square-cm-seconds in the post-big-bang observable universe, which is about 15 times the original target of 2^200. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So if we want to go with that perfectly arbitrary estimate of life probability and perfectly arbitrary estimate of the reference area for an orbiting object, we might reasonably estimate 15 tech-enabled civilizations, out there somewhere, possibly in this small patch of sky:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://www.google.com/imgres?imgurl=http://www.thespiritualeclectic.com/wp-content/uploads/2010/01/nasa1.jpg&imgrefurl=http://www.thespiritualeclectic.com/2010/01/18/mid-life-options-where-do-we-go-from-here/&h=600&w=800&sz=63&tbnid=3Z4m2wYqx3s7FM:&tbnh=89&tbnw=119&zoom=1&usg=__ekjgCXYJE1oVVIqP5vMlpiW5czY=&docid=PETZDSnWCDTFqM&hl=en&sa=X&ei=WjkkUdPaFeXAiwLI64GADg&ved=0CFMQ9QEwCg&dur=140">http://www.google.com/imgres?imgurl=http://www.thespiritualeclectic.com/wp-content/uploads/2010/01/nasa1.jpg&imgrefurl=http://www.thespiritualeclectic.com/2010/01/18/mid-life-options-where-do-we-go-from-here/&h=600&w=800&sz=63&tbnid=3Z4m2wYqx3s7FM:&tbnh=89&tbnw=119&zoom=1&usg=__ekjgCXYJE1oVVIqP5vMlpiW5czY=&docid=PETZDSnWCDTFqM&hl=en&sa=X&ei=WjkkUdPaFeXAiwLI64GADg&ved=0CFMQ9QEwCg&dur=140</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Do stare at this photo for a while please, until it stares back, then remind me, what were we talking about?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>spike<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></div></body></html>