<story><title>Model predicts we&apos;re the only advanced civilization in the observable universe</title><url>https://www.universal-sci.com/headlines/2018/6/22/new-model-predicts-that-were-probably-the-only-advanced-civilization-in-the-observable-universe</url></story><parent_chain><item><author>raducu</author><text>Actually Fermi&amp;#x27;s paradox makes total sense to me:&lt;p&gt;- Presume that even with something like travel at 1% o speed of light, the Milky Way is colonizable in a couple of million years.&lt;p&gt;- Presume that we are not special at all and there exist more technological advanced civilizations that predate us by at least a couple million years&lt;p&gt;- Presume such a large scale colonization would be easy to observe&lt;p&gt;If you accept the 3 presuppositions, the only logical conclusion is that there are no other technologically advanced species in the Milky Way or that we&amp;#x27;re the first(very unlikely).&lt;p&gt;Or you can choose to attack any of the presuppositions, but that&amp;#x27;s also very hard in my humble oppinion.</text></item><item><author>bambax</author><text>Yes, the Drake equation seems quite pointless because multiplying many unknowns by one another doesn&amp;#x27;t reduce uncertainty, it increases it. I don’t know anything about the history of the Drake equation, but it looks possible it was devised to demonstrate the unknownability of the result, rather than a tool to help find it.&lt;p&gt;Also, the article seems to use &amp;quot;our galaxy&amp;quot; and &amp;quot;the universe&amp;quot; as interchangeable terms, which of course they are not.&lt;p&gt;I don’t see how the Fermi paradox is a paradox: given the distances involved and what we know about the speed of light, an alien civilization would have had to develop a very long time ago in order to send signals that we would be able to detect today. Just because, maybe, no civilization was able to do that a billion years ago doesn’t mean nothing happened since (as you say, at least we happened).&lt;p&gt;We just don’t know.</text></item><item><author>frisco</author><text>So, I read this paper and was pretty unconvinced. I think the premise of using a Monte Carlo analysis is flawed because &lt;i&gt;of course&lt;/i&gt; multiplying together wide ~iid distributions that have big near-zero components asymptotes to zero; unless I&amp;#x27;m misunderstanding something, this is essentially the central limit theorem. (All of the parameter samples below 1e0 drag the total outcome towards zero since probabilities are bounded &amp;gt;= 0)  Thus, the real information is still strongly dominated by beliefs about the width and centering of the distributions, which we still don&amp;#x27;t know, and as long as enough of the parameters have high uncertainty with some potentially having near-zero values, the result will always tend towards zero.&lt;p&gt;I think what this analysis tell us is that if you don&amp;#x27;t think it&amp;#x27;s possible to get better, more specific values for the parameters, the Drake Equation is just a bad tool.&lt;p&gt;Also, the Drake Equation doesn&amp;#x27;t describe the number of alien civilizations, it describes the likely number of civilizations. Thus, extremely pessimistic estimates have to somehow correct for the fact that we know N is not zero, since we are here. That seems like a highly informative update that is not addressed in an interesting way.</text></item></parent_chain><comment><author>krapp</author><text>&amp;gt; Presume that even with something like travel at 1% o speed of light, the Milky Way is colonizable in a couple of million years.&lt;p&gt;You&amp;#x27;re not assuming that it is, you&amp;#x27;re assuming that if it can be, it must be.&lt;p&gt;Which assumes that every part of the milky way is equally amenable to colonization, as if the galaxy were merely points laid out on a Cartesian grid, and that any species capable of colonizing one star must continue to colonize them all.&lt;p&gt;You must consider the case of technologically advanced species incapable of colonizing other stars, and technologically advanced species capable of colonizing other stars, but unwilling to do so on a large scale, or attempts at large scale colonization which fail across a scale of millions of years or even attempts to hide the obvious presence of such colonization from observers.&lt;p&gt;&amp;gt;Presume that we are not special at all and there exist more technological advanced civilizations that predate us by at least a couple million years&lt;p&gt;Ok.&lt;p&gt;&amp;gt;Presume such a large scale colonization would be easy to observe&lt;p&gt;By humans, given that we only recently became aware that extrasolar planets are even a thing, and have only been studying the universe with anything but optical telescopes for less than a century, and don&amp;#x27;t even know what the signs of &amp;quot;large scale colonization&amp;quot; would look like. No. Why?&lt;p&gt;&amp;gt;Or you can choose to attack any of the presuppositions, but that&amp;#x27;s also very hard in my humble oppinion.&lt;p&gt;Any argument can seem airtight when you refuse to consider more than a single case to be valid.</text></comment>
<story><title>Model predicts we&apos;re the only advanced civilization in the observable universe</title><url>https://www.universal-sci.com/headlines/2018/6/22/new-model-predicts-that-were-probably-the-only-advanced-civilization-in-the-observable-universe</url></story><parent_chain><item><author>raducu</author><text>Actually Fermi&amp;#x27;s paradox makes total sense to me:&lt;p&gt;- Presume that even with something like travel at 1% o speed of light, the Milky Way is colonizable in a couple of million years.&lt;p&gt;- Presume that we are not special at all and there exist more technological advanced civilizations that predate us by at least a couple million years&lt;p&gt;- Presume such a large scale colonization would be easy to observe&lt;p&gt;If you accept the 3 presuppositions, the only logical conclusion is that there are no other technologically advanced species in the Milky Way or that we&amp;#x27;re the first(very unlikely).&lt;p&gt;Or you can choose to attack any of the presuppositions, but that&amp;#x27;s also very hard in my humble oppinion.</text></item><item><author>bambax</author><text>Yes, the Drake equation seems quite pointless because multiplying many unknowns by one another doesn&amp;#x27;t reduce uncertainty, it increases it. I don’t know anything about the history of the Drake equation, but it looks possible it was devised to demonstrate the unknownability of the result, rather than a tool to help find it.&lt;p&gt;Also, the article seems to use &amp;quot;our galaxy&amp;quot; and &amp;quot;the universe&amp;quot; as interchangeable terms, which of course they are not.&lt;p&gt;I don’t see how the Fermi paradox is a paradox: given the distances involved and what we know about the speed of light, an alien civilization would have had to develop a very long time ago in order to send signals that we would be able to detect today. Just because, maybe, no civilization was able to do that a billion years ago doesn’t mean nothing happened since (as you say, at least we happened).&lt;p&gt;We just don’t know.</text></item><item><author>frisco</author><text>So, I read this paper and was pretty unconvinced. I think the premise of using a Monte Carlo analysis is flawed because &lt;i&gt;of course&lt;/i&gt; multiplying together wide ~iid distributions that have big near-zero components asymptotes to zero; unless I&amp;#x27;m misunderstanding something, this is essentially the central limit theorem. (All of the parameter samples below 1e0 drag the total outcome towards zero since probabilities are bounded &amp;gt;= 0)  Thus, the real information is still strongly dominated by beliefs about the width and centering of the distributions, which we still don&amp;#x27;t know, and as long as enough of the parameters have high uncertainty with some potentially having near-zero values, the result will always tend towards zero.&lt;p&gt;I think what this analysis tell us is that if you don&amp;#x27;t think it&amp;#x27;s possible to get better, more specific values for the parameters, the Drake Equation is just a bad tool.&lt;p&gt;Also, the Drake Equation doesn&amp;#x27;t describe the number of alien civilizations, it describes the likely number of civilizations. Thus, extremely pessimistic estimates have to somehow correct for the fact that we know N is not zero, since we are here. That seems like a highly informative update that is not addressed in an interesting way.</text></item></parent_chain><comment><author>rdtsc</author><text>&amp;gt;  Milky Way is colonizable in a couple of million years.&lt;p&gt;I have two takes on it:&lt;p&gt;1) We don&amp;#x27;t know the possible implication of new discoveries. Well, actually we get some glimpse of it, for example with nuclear or biological weapons around, it is fairly easy to wipe out a large part of the population. The more advanced the technology becomes it seems there is a higher chance of it blowing up in our faces and us destroying ourselves. So the galaxy could be colonizable in a few million years, but any civilization headed closer to that ability, gets closer (and faster) to its own destruction as well.&lt;p&gt;&amp;gt; The only logical conclusion is that there are no other technologically advanced species in the Milky Way or that we&amp;#x27;re the first(very unlikely).&lt;p&gt;Given my other pessimistic take on it (1), I would say it likely there were (are) quite a few technologically advanced species, but they&amp;#x27;ve wiped themselves out or will do so before the reach the ability to colonize planets in other galaxies.&lt;p&gt;2) Another take on it is these civilization have to share the same physics and chemistry that we do. And maybe there is just a limit that gets achieved and long term colonization or fast travel is just no possible. That is there are no shortcuts like wormholes, Alcubierre drives, antigravity and other such things. We&amp;#x27;ve been used to seeing huge leaps in technology and science in the last 1000 years, so it&amp;#x27;s tempting to extrapolate and but maybe we are close to reaching a wall. So there are quite a few civilizations out there but they&amp;#x27;ve flown probes in their own start system, now developed internet and are sharing pictures of alien cats, hanging out on their version of Facebook and watching their alien Netflix, and of course discussing their equivalent of Fermi&amp;#x27;s Paradox on online forums. All without a chance of ever leaving their neighborhood.</text></comment>