<story><title>An approximation to determine the source of the WOW! Signal</title><url>https://www.cambridge.org/core/journals/international-journal-of-astrobiology/article/an-approximation-to-determine-the-source-of-the-wow-signal/4C58B6292C73FE8BF04A06C67BAA5B1A</url></story><parent_chain><item><author>slimsag</author><text>No stake in this game, but your likeliness assumption depends on the idea that a civilization &lt;i&gt;could&lt;/i&gt; get to the point of creating a Dyson Swarm. If civilizations are statistically likely to destroy themselves before then, &amp;#x27;detecting a few decades of radio emissions&amp;#x27; could be the only scenario.</text></item><item><author>jmyeet</author><text>Not the first time I&amp;#x27;ve said this but it&amp;#x27;s highly unlikely that we&amp;#x27;ll detect technological civilizations through radio emissions. We&amp;#x27;ve had this kind of radio emission but it&amp;#x27;s incredibly brief so for Earth, you&amp;#x27;d have to be listening for a few decades over the billions of years Earth has existed. That&amp;#x27;s incredibly unlikely.&lt;p&gt;The far more likely detection method is IR signatures, specifically from Dyson Swarms. A Dyson Swarm is not a rigid sphere (a confusion caused in part by the original name &amp;quot;Dyson Sphere&amp;quot;). It is a collection of orbitals with the intent of making full use of a star&amp;#x27;s energy output. The beauty of this is it&amp;#x27;s all rather low-tech needing little more than solar power, stainless steel level materials science and (this is the big one but is an engineering problem not a science one) getting access to basic raw materials.&lt;p&gt;Just like a cloud looks solid despite being water droplets, a complete Dyson Swarm would be the same. The visible light would be blocked out.&lt;p&gt;But here&amp;#x27;s where the IR part comes in. The only way to dissipate heat in space is to radiate it away. A habitat will have to do this. At any reasonable temperature the signature of that radiated heat is as IR radiation determined by the temperature of the radiating object. That&amp;#x27;s physics.&lt;p&gt;So if you see stars with low visible light output but shines like a beacon in the IR specturm (comparatively) that&amp;#x27;s a good candidate for a Dyson Swarm because stars don&amp;#x27;t otherwise look anything like that. This is what makes any &amp;quot;Hidden Aliens&amp;quot; type scenarios rather implausible. You just can&amp;#x27;t hide these things.&lt;p&gt;Let me add this perspective: on Earth we consume (IIRC) about 10^11 Watts of energy. The Sun&amp;#x27;s energy output is in the order of 10^26 Watts. It is almost unfathomable what you could do with that much power. That&amp;#x27;s using humanity&amp;#x27;s entire energy consumption about every &lt;i&gt;30 nanoseconds&lt;/i&gt;.&lt;p&gt;So what&amp;#x27;s more likely: 1. Detecting a few decades of radio emissions or 2. the IR signature of what would likely be millions of years?&lt;p&gt;So I applaud any investigation into the wow! signal just like I do of FRBs. We should understand likely causes but technological life? It almost certainly isn&amp;#x27;t.</text></item></parent_chain><comment><author>oceanplexian</author><text>Or civilizations find a better way to generate energy.&lt;p&gt;Why would you build this big mass around a star when you can create your own, much more efficient fusion reactor where and when you need it? Stars are insanely inefficient; they convert less than 1% of their mass into energy, take billions of years to do it, and you can’t turn them off when you aren’t using them. Plus, if you wanted to use it for some exotic warp drive or something, you would have to haul the mass of a star around. None of it really makes sense to me.</text></comment>
<story><title>An approximation to determine the source of the WOW! Signal</title><url>https://www.cambridge.org/core/journals/international-journal-of-astrobiology/article/an-approximation-to-determine-the-source-of-the-wow-signal/4C58B6292C73FE8BF04A06C67BAA5B1A</url></story><parent_chain><item><author>slimsag</author><text>No stake in this game, but your likeliness assumption depends on the idea that a civilization &lt;i&gt;could&lt;/i&gt; get to the point of creating a Dyson Swarm. If civilizations are statistically likely to destroy themselves before then, &amp;#x27;detecting a few decades of radio emissions&amp;#x27; could be the only scenario.</text></item><item><author>jmyeet</author><text>Not the first time I&amp;#x27;ve said this but it&amp;#x27;s highly unlikely that we&amp;#x27;ll detect technological civilizations through radio emissions. We&amp;#x27;ve had this kind of radio emission but it&amp;#x27;s incredibly brief so for Earth, you&amp;#x27;d have to be listening for a few decades over the billions of years Earth has existed. That&amp;#x27;s incredibly unlikely.&lt;p&gt;The far more likely detection method is IR signatures, specifically from Dyson Swarms. A Dyson Swarm is not a rigid sphere (a confusion caused in part by the original name &amp;quot;Dyson Sphere&amp;quot;). It is a collection of orbitals with the intent of making full use of a star&amp;#x27;s energy output. The beauty of this is it&amp;#x27;s all rather low-tech needing little more than solar power, stainless steel level materials science and (this is the big one but is an engineering problem not a science one) getting access to basic raw materials.&lt;p&gt;Just like a cloud looks solid despite being water droplets, a complete Dyson Swarm would be the same. The visible light would be blocked out.&lt;p&gt;But here&amp;#x27;s where the IR part comes in. The only way to dissipate heat in space is to radiate it away. A habitat will have to do this. At any reasonable temperature the signature of that radiated heat is as IR radiation determined by the temperature of the radiating object. That&amp;#x27;s physics.&lt;p&gt;So if you see stars with low visible light output but shines like a beacon in the IR specturm (comparatively) that&amp;#x27;s a good candidate for a Dyson Swarm because stars don&amp;#x27;t otherwise look anything like that. This is what makes any &amp;quot;Hidden Aliens&amp;quot; type scenarios rather implausible. You just can&amp;#x27;t hide these things.&lt;p&gt;Let me add this perspective: on Earth we consume (IIRC) about 10^11 Watts of energy. The Sun&amp;#x27;s energy output is in the order of 10^26 Watts. It is almost unfathomable what you could do with that much power. That&amp;#x27;s using humanity&amp;#x27;s entire energy consumption about every &lt;i&gt;30 nanoseconds&lt;/i&gt;.&lt;p&gt;So what&amp;#x27;s more likely: 1. Detecting a few decades of radio emissions or 2. the IR signature of what would likely be millions of years?&lt;p&gt;So I applaud any investigation into the wow! signal just like I do of FRBs. We should understand likely causes but technological life? It almost certainly isn&amp;#x27;t.</text></item></parent_chain><comment><author>jmyeet</author><text>In the context of the Fermi Paradox, that&amp;#x27;s not really an issue. Let me explain.&lt;p&gt;Imagine the chance of a civilization getting from our point to a Dyson Swarm without destroying themselves is 1% for wahtever reasons you like. If there are 10,000 equivalents to us within 10,000 light years it becomes incredibly likely we won&amp;#x27;t see one of these. You can argue we&amp;#x27;re &amp;quot;first&amp;quot; but being &amp;quot;first&amp;quot; out of 100 or 10,000 civilizations gets unlikely.&lt;p&gt;Now imagine there are 5 instead of 10,000. Then not seeing any gets much more likely.&lt;p&gt;So my point is that not seeing any evidence of these so far is still evidence of something and that something is most likely to be that civilizations reaching even our point is rare.&lt;p&gt;As for destruction of a species at our point, that&amp;#x27;s a whole separeate avenue of discussion. But the short version is that this is incredibly likely. Even if all the superviruses get released and all the nuclear weapons get detonated humanity will still likely survive.&lt;p&gt;A lot of our advances were delayed not because that advance is hard but because we didn&amp;#x27;t know any better and just coming up with that idea is the problem. Once you know the structure of matter and ideas like smelting steel (which is realtively low tech) can be recovered way quicker than they&amp;#x27;re lost.&lt;p&gt;1,000 years ago we were throwing spears at each other. A little over 100 years ago we took our first flight. In the last 50+ years we&amp;#x27;ve gone from landing on the Moon to reducing LEO payload costs from $50,000+&amp;#x2F;kg to arguably &amp;lt;$1,000&amp;#x2F;kg and it&amp;#x27;s likely in the next 20 years that&amp;#x27;ll come down to possibly as low as $100&amp;#x2F;kg.&lt;p&gt;Barring some cosmic catastrophe it seems that permanent habitation of orbitals within the next 1,000 is pretty conservative.</text></comment>