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The great filter is nuclear weapons, because as soon as a civilization discovers them a nuclear war breaks out fairly quickly, sending the civilizations on the planet back to the stone age. Eventually civilization bounces back, only to rediscover nuclear weapons and go right back to the stone age with another nuclear war. Rinse and repeat until there is no more nuclear material on the planet. At that point there is no more nuclear war, but civilization also can't build nuclear-pulse propelled rockets to colonize the galaxy, so they are stuck on their planet forever. It also neatly explains the lack of lithium-7 in the universe, since the planet's lithium supply would be used in the production of nuclear weapons. And we haven't detected any alien electromagnetic radiation because there are still a relatively small amount of habitable planets in the galaxy and we haven't scanned enough of the sky yet to discover them.
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Nov 29, 2018 18:56
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| # ¿ May 11, 2024 22:36 |
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Owlofcreamcheese posted:What is "alien electromagnetic radiation" though? It's not like it'd glow green and have extra eyes or something. Radiation that has complex patterns in it. For example digital human radio signals are usually divided into chunks.
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Nov 29, 2018 19:24
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thegalagakid posted:Maybe we're under some kind of galactic quarantine until we get to the point where we either pose enough of a threat for a direct intervention or we sort out ourselves at least enough to develop a reasonable society and FTL space travel, and then they make some direct contact. I have nothing concrete to base this on, but we do it on Earth with remote tribes (the missionary recently that got killed on that forbidden island for instance). I can reasonably see a far more advanced nearby civilization doing that with us. The nearest star is about 4 lightyears away and we don't have anything like the technology it would take to reach it in a reasoable frame of time, so we're effectively self-contained. Actually using current technology humans can colonize the entire Milky Way galaxy in about a million years. This finding is what pushed many into the Great Filter camp.
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Nov 29, 2018 21:40
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Solaris 2.0 posted:I always figured a "hive-mind" like species could conquer space. There would be no factions, no intra-conflict, no individuality or wants or need, and with that an effective use of resources to keep the home-planet sustainable (no civilization killing climate change). I have some bad news about intra-hive conflicts between hive-mind Earth-based species.
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Nov 29, 2018 22:10
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I don't think it's so much intelligence that separates humans from, say, chimps, but rather education. Homo Sapiens 50,000 years ago would not have appeared to be much more advanced than chimps; they'd be living in caves and using simple tools to hunt. But what allowed humans to jump so far ahead of other animals is the invention of language, where older humans could teach younger humans things, and that allowed knowledge to build up so new humans didn't have to relearn everything from scratch and could spend their time learning new things about the world instead.
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Dec 2, 2018 04:17
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suck my woke dick posted:short answer: read the killing star Couldn't this relativistic kinetic weapon be easily countered by just putting some rocks in front of its path? For example if the missile has a mass of 100 kg and is travelling at .99c, then if it collides head-on with a 100 kg rock then its speed will be halved, to preserve momentum, which means that its kinetic energy goes down four times, with the rest of the energy converted into heat and radiation. With enough rocks in the missile's path its kinetic energy can be reduced to negligible amounts.
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Dec 6, 2018 02:33
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Morbus posted:How do you know where to put the rock? Hmm, this makes me wonder, what will it actually look like to observe this relativistic missile as it approaches Earth? It takes about 7 hours for light to reach from Pluto's highest orbit to Earth. So if by chance we have a telescope pointed directly at the missile, then we'll observe its light 7 hours after it enters the Solar System, but if it's traveling at .99c it means that it will collide with Earth almost right after it is observed. This makes it seem that if we are observing it then we'd see that it appears to be travelling much faster than the speed of light, since we'd go from seeing it enter the Solar System to seeing it crash into Earth almost instantaneously.
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Dec 6, 2018 03:06
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The Butcher posted:In The Expanse they basically just painted the rocks they dropped on Earth with black radar absorptive paint, fired them up to owie speed, then turned off the engines and just let them sail. Deep space still has tiny amounts of matter floating around, so this relativistic missile will collide with that matter and accelerate it so much that it will release gamma rays, which could then be detected.
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Dec 6, 2018 05:56
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A division algorithm can be built from a multiplication algorithm combined with a binary search. For example to solve 100/8 you would first make a guess, like 4, then multiply by 8, which is 32 and less than 100. So then you try 8*8 = 64, still too low. Then try 16, whoops too high. Then 12, etc, until you get to 12.5. This puts an upper bound on the runtime of a division algorithm to the runtime of the multiplication algorithm times log(n), which is polynomial in time.
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Dec 6, 2018 06:36
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| # ¿ May 11, 2024 22:36 |
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Maybe all of the asteroids that caused extinction events on Earth were launched by aliens trying to prevent intelligent life from emerging on Earth 
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Dec 11, 2018 08:04
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