SETI@home shuts down after 21 years
Not to sound like a broken record (I and others have said this or similar on these kinds of threads) but... I, personally, have become convinced that looking for signals this way is actually pointless.The argument is basically this:1. Within 1000 years (and maybe a lot less) we will have the engineering capability to build space habitats, powered by solar power. This last part is important because this thought experiment isn't gated on commercial viability of nuclear fusion power, which I'm not yet convinced is possible.2. These space habitats are far more efficient at creating living area than planets. I forget the exact numbers but something like 1% of the mass of Mercury is enough to create enough living area for something like 10^16 to 10^18 people.3. Space habitats are more convenient and cheaper to move between than leaving or even entering a gravity well like Earth's.4. Roughly one billionth of the Sun's energy hits the Earth.5. Once you have the ability to create one of these things, each becomes progressively easier.This, of course, is the classic Dyson Swarm. Originally this was called a Dyson Sphere but this has led some to think it's a solid shell around a star. That was never the intent. Even if it was, no known or currently theorized material could support this.Dyson Swarms are not subtle. Even a partial Dyson Swarm should be detectable as a large IR source compared to how much visible light is produced. This is because the only way for something in space to cool down is to radiate that heat away and physics determines the wavelength of that based on the temperature of the object.Standard objection: what if you can recycle that heat? Well, you can't do that perfectly (as this would violate Thermodynamics) and even if you reduce IR emissions by 90%, you've simply reduced the IR emissions by one order of magnitude. For comparison, the Sun produces roughly 4x10^26 Watts of power.So if you accept the above premises the gap between stabbing each other with swords and having this technology, at least for us, is 1000-2000 years, a cosmic blink of an eye to produce signals without the above IR signature. Those are long odds.Personally I subscribe to the view that technological life is, at least within a billion light years of us, is likely quite rare.The above is a very superficial summary of a topic that Isaac Arthur's channel goes into great depth about. I guarantee you any objection you have has at least one video that goes into that in great depth.