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| ▲ | Zigurd 8 days ago | parent | next [-] | | Yes. Most people don't understand either physical and chronological distance enough to understand that contact with an alien civilization, if it exists or ever did exist, is vanishingly unlikely to happen because of time, physical changes to solar systems, distance, the endurance of civilizations, the speed of light, etc. Loeb is pandering to the UFO-susceptible. | | |
| ▲ | 0xDEAFBEAD 8 days ago | parent | next [-] | | "Endurance of civilizations" is the key parameter here. The universe is almost 14 billion years old. Colonizing the Milky Way only takes 1 million years if you can travel 10% of the speed of light. So time and distance aren't significant obstacles for a highly enduring civilization. Given our massive uncertainty about the endurance/motives/etc. of super-advanced starfaring civiliations, I don't think it's justified to say that alien interlopers are "vanishingly unlikely". | | |
| ▲ | giantrobot 8 days ago | parent | next [-] | | > Colonizing the Milky Way only takes 1 million years if you can travel 10% of the speed of light. This statement comes up all the time as if it automatically wins any discussion of alien civilizations. It contains a number of huge possibly specious assumptions. The first and most obvious is that even a long-lived civilization could construct a technology allowing a non-trivial amount of mass to accelerate to 0.1c and more importantly decelerate at the destination to a relative velocity of zero to facilitate the colonization. | | |
| ▲ | asdff 8 days ago | parent | next [-] | | Also a lot of assumptions about mutation rate. Anatomically modern humans appeared 300k years ago. Behaviorally modern humans appeared 50k years ago. A species beginning colonization on one end of the galaxy might not be the same species at all by the time it reached the other end of the galaxy a million years later. There might be a whole spectrum of new species that emerged along the way. | | |
| ▲ | 0xDEAFBEAD 8 days ago | parent | next [-] | | It seems to me that such speciation supports the assumption of endurance. Over time you'd see selection for species which are patient, diligent, fecund star colonizers. Just like medieval Europeans spent decades or centuries building a cathedral, over time you'd select for species which spend centuries working on their next starshot. | | |
| ▲ | syncmaster913n 8 days ago | parent | next [-] | | "Over time you'd see selection for species which are patient, diligent, fecund star colonizers." Or for species that excel at command-deck politics. | |
| ▲ | asdff 7 days ago | parent | prev [-] | | Depends on if the explorers are the ones doing the bulk of the breeding. On planet earth, educated people actually tend to have fewer kids. There is therefore selective pressure against intelligence on earth. |
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| ▲ | grumbelbart2 8 days ago | parent | prev [-] | | I'd expect the first exploration to be done by machines, and digital transfer of the controlling instance would remove almost all drift. | | |
| ▲ | asdff 7 days ago | parent [-] | | Machines suffer mutation rate too. Cosmic ray induced bitflips could be possible. Although since we are all spitballing anyhow maybe you can handwave a cosmic shield along with your cosmic explorer. It would also be interesting if the host system collapsed. That would be some interesting scifi fodder: advanced civilization sends out probes but by the time FTL visitors show up, their civilization already collapsed to the stone age. |
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| ▲ | 0xDEAFBEAD 8 days ago | parent | prev | next [-] | | >The first and most obvious is that even a long-lived civilization could construct a technology allowing a non-trivial amount of mass to accelerate to 0.1c and more importantly decelerate at the destination to a relative velocity of zero to facilitate the colonization. Is there any reason to believe this should be impossible, in principle? Note my use of the word "impossible", as opposed to "extremely difficult". The colonization timeline is still the same order of magnitude if it takes 100,000 years of research and engineering to crack the problem. Think about what humanity has achieved in the past 50 years, then multiply by 2000. | | |
| ▲ | earnestinger 8 days ago | parent [-] | | It’s unknown. It can equally be possible, impossible or not worth it. Interstellar rocks crashing at you with velocity of 0.1c might hurt a lot. I would not like my government spending 99% of everybodies income for 100 generations, just to send one human to proxima centauri. Growth and efficiency gains are not guaranteed, and will eventually stop.
(If you take the mass of universe, put it into mc^2, and assume 5% energy consumption increase per year you get 2k years to consume whole universe worth of energy) We can’t just assume that humans will reach Proxima Centauri. |
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| ▲ | api 8 days ago | parent | prev [-] | | And then do that gargantuan feat more than once, with every colony growing exponentially until it can do it again. We haven’t been back to the moon. Maybe some much more advanced civilization would do one star shot, found one colony, and be like awesome now we are in two solar systems and that’s enough. A solar system is huge. It’s probably a lot easier to terraform terrestrial planets or build a living Dyson swarm of Stanford toruses than build a starship. Certainly easier than building more than one starship. The human race could probably expand for hundreds of thousands of years in this solar system before we would ever feel any actual pressure to go elsewhere. | | |
| ▲ | 0xDEAFBEAD 8 days ago | parent [-] | | >Maybe some much more advanced civilization would do one star shot, found one colony, and be like awesome now we are in two solar systems and that’s enough. There are over 100 billion stars in the Milky Way alone. Your statement might be true for 99% of civs, yet the remaining 1% are still gigacolonizers. >It’s probably a lot easier to terraform terrestrial planets or build a living Dyson swarm of Stanford toruses than build a starship. Certainly easier than building more than one starship. The human race could probably expand for hundreds of thousands of years in this solar system before we would ever feel any actual pressure to go elsewhere. If you're Kardashev type 2, what are you going to do with all of that energy anyways? Why not give your Stanford toruses sublight engines, and turn them into superfast interstellar cruise ships full of amenities? Lawnchair Larry said it well: "A man can't just sit around." |
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| ▲ | timuckun 8 days ago | parent | prev [-] | | Have ever seen anything bigger than a bread box travel at 10% of the speed of light? Also your timeline presumes self replicating spaceships exist or could exist. Have you ever thought about what kind of spaceship could mine metals, smelt them, make glass, build a chip fab etc? | | |
| ▲ | david-gpu 7 days ago | parent [-] | | > Have ever seen anything bigger than a bread box travel at 10% of the speed of light? The sort of technological capabilities we have today would sound laughable to people a mere thousand years ago. Who knows what will be doable in a few million years, which is a blink in the grand scheme of the cosmos. |
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| ▲ | api 8 days ago | parent | prev | next [-] | | We have no idea. There are multiple unknown parameters in that sentence. We can’t say it’s likely or unlikely. | |
| ▲ | throwawaymaths 8 days ago | parent | prev [-] | | what do you think of this? https://www.researchgate.net/publication/394040040_Aligned_m... | | |
| ▲ | Zigurd 8 days ago | parent [-] | | I don't think too highly of this, from the abstract: Notably, the candidate coincides in time with the Washington D.C. 1952 UFO flyover, and another (a candidate) falls within a day of the peak of the 1954 UFO wave | | |
| ▲ | throwawaymaths 8 days ago | parent [-] | | wow. ok. didn't even look at the data. the crazy thing is that you are so biased against these researchers that you have even shut out the possibility that these (and the DC UFOs) are extremely high formation flying USAF vehicles (for example). |
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| ▲ | poulpy123 7 days ago | parent | prev | next [-] | | That's simple: clickbait speculation is not science | |
| ▲ | Muromec 8 days ago | parent | prev | next [-] | | The only reason is us declaring it seacular matter | |
| ▲ | moi2388 7 days ago | parent | prev [-] | | No. But claiming that a comet, which we know is a comet, might be a potentially hostile alien spacecraft is it the very least dishonest, but if claim also unfair and harmful for the general public and how they think about science. I don’t buy for a second Avi Loeb actually believes this; it’s just to up his citation index. I think it’s disgusting. |
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