<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>The energy that kills an entire galaxy would be released as hard gamma rays. "Hot enough to break nuclei at 50,000 light years" (Egan's Diaspora)</div><div><br>On Feb 11, 2016, at 6:50 PM, spike <<a href="mailto:spike66@att.net">spike66@att.net</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="Generator" content="Microsoft Word 15 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--><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><div><div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> extropy-chat [<a href="mailto:extropy-chat-bounces@lists.extropy.org">mailto:extropy-chat-bounces@lists.extropy.org</a>] <b>On Behalf Of </b>Anders Sandberg<br></span><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">…</span></b><br><br><span style="color:#1F497D">>…</span>If we assume the energy release was around 10^50 J over a second, then the power per square meter at distance d is 10^50/(4 pi r^2) Watts. So the criticial distance if the danger power is P is r=sqrt(10^50/4 pi P). If we assume a megawatt/m^2 is enough to cause biosphere damage, then the distance is 298,000 lightyears. To wipe out more advanced civilizations I would expect a much higher P; for a gigawatt the range is 9,400 lightyears - bad in the central part of a galaxy, but not even covering it<span style="color:#1F497D">…<o:p></o:p></span></p></div></div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D">Anders, cool, but we need to know how GW energy would interact with matter before we conclude that it would nuke biomes. <o:p></o:p></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D">spike<o:p></o:p></span></p><pre><o:p> </o:p></pre></div></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>extropy-chat mailing list</span><br><span><a href="mailto:extropy-chat@lists.extropy.org">extropy-chat@lists.extropy.org</a></span><br><span><a href="http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat">http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat</a></span><br></div></blockquote></body></html>