What If Humanity Is Among The First Spacefaring Civilizations?Our biggest worry may be the aliens we can't see
"There is no practical use of space quite yet."Really? I admit that Mars rovers might not qualify as practical, but why are communications, environmental monitoring, GPS, surveillance, and so on not practical? Or are you only counting crewed flight as spacefaring? If so I don't agree with that limitation.
Quote from: Phil Stooke on 11/12/2022 09:18 pm"There is no practical use of space quite yet."Really? I admit that Mars rovers might not qualify as practical, but why are communications, environmental monitoring, GPS, surveillance, and so on not practical? Or are you only counting crewed flight as spacefaring? If so I don't agree with that limitation. I am talking about space. We (the humans) do very small steps on the "walking distance" from our home. Mars rovers etc. are just very few experiments on the level of first pre Columbus experiments with the sea navigation. Small experiments is not use. They are just experiments, the knowledge they provide is very conditional and almost always very situational. The data about Mars are practical if Mars will be ever used. Which is not.
More of it it's quite easy to make very solid arguments that generally "Space" drive is about to end completely and there will be nothing after. Your country (just like the rest of the world) is undergoing through very significant social and cultural changes. Basically confucian nonsense (moral licensing is a powerful drug) is winning the world. I remind that most human present civilizations are static historically and are focused on the past.
Quote from: dondar on 11/13/2022 09:52 amQuote from: Phil Stooke on 11/12/2022 09:18 pm"There is no practical use of space quite yet."Really? I admit that Mars rovers might not qualify as practical, but why are communications, environmental monitoring, GPS, surveillance, and so on not practical? Or are you only counting crewed flight as spacefaring? If so I don't agree with that limitation. I am talking about space. We (the humans) do very small steps on the "walking distance" from our home. Mars rovers etc. are just very few experiments on the level of first pre Columbus experiments with the sea navigation. Small experiments is not use. They are just experiments, the knowledge they provide is very conditional and almost always very situational. The data about Mars are practical if Mars will be ever used. Which is not.Phil admits that "Mars rovers might not qualify as practical," but you never address the second half of his post.
Quote from: Phil Stooke on 11/12/2022 09:18 pm"There is no practical use of space quite yet."Really? I admit that Mars rovers might not qualify as practical, but why are communications, environmental monitoring, GPS, surveillance, and so on not practical? Or are you only counting crewed flight as spacefaring? If so I don't agree with that limitation. In English "seafaring" comes from a combination of "sea" and the Germanic word for "journey" via Middle English and its strong German roots. It literally means "sea journey". Changing what is being traveled on/in gives us "spacefaring" or "space journey/travel". None of the uses you mention involve travel. They just whiz around the Earth, never leaving or arriving. The GEO satellites don't even do that relative to the Earth. Crew or no crew, they're not traveling. The general public understands that at a gut level and that's one of the main reasons that it lost interest in space once Apollo ended.If a true spacefaring society is equivalent to at least the Phoenicians and Vikings, what we have now is the riverside society with canoes to tend the fish traps and weirs and some people spending time in a duck blind out in the middle of the river (ISS).
I have a sneaking suspicion that before a civilization can become truly interstellar, they are exterminated by their machines, who then go dark.
Quote from: laszlo on 11/13/2022 11:13 amQuote from: Phil Stooke on 11/12/2022 09:18 pm"There is no practical use of space quite yet."Really? I admit that Mars rovers might not qualify as practical, but why are communications, environmental monitoring, GPS, surveillance, and so on not practical? Or are you only counting crewed flight as spacefaring? If so I don't agree with that limitation. In English "seafaring" comes from a combination of "sea" and the Germanic word for "journey" via Middle English and its strong German roots. It literally means "sea journey". Changing what is being traveled on/in gives us "spacefaring" or "space journey/travel". None of the uses you mention involve travel. They just whiz around the Earth, never leaving or arriving. The GEO satellites don't even do that relative to the Earth. Crew or no crew, they're not traveling. The general public understands that at a gut level and that's one of the main reasons that it lost interest in space once Apollo ended.If a true spacefaring society is equivalent to at least the Phoenicians and Vikings, what we have now is the riverside society with canoes to tend the fish traps and weirs and some people spending time in a duck blind out in the middle of the river (ISS).An interesting link regarding the question of whether mankind could truly become the first spacefaring civilization:https://www.forbes.com/sites/startswithabang/2020/10/14/are-humans-earths-best-chance-to-become-a-spacefaring-civilization/?sh=5f1ec26b7d84
Grabby aliens again. Don’t like that theory. Basically built on the assumption that because we don’t see evidence of them out there, they must be expanding fairly close to the speed of light, to account for the fact that their visible light does not reach us significantly before they do.Requiring a rather contrived constraint that the older they are, the further away they are (to avoid a situation where a billion year old civilization is in e.g. the Andromeda galaxy, which should have made it visible to us within at most a few million years, so hundreds of millions years ago from the present).Why would older civilizations necessarily be more distant from us. There is no logical reason for that to be the case.The simpler alternative is that they’re just not there in the first place.
good example of why American habit of early specialization in .... sucks.
Quote from: M.E.T. on 11/12/2022 07:05 amGrabby aliens again. Don’t like that theory. Basically built on the assumption that because we don’t see evidence of them out there, they must be expanding fairly close to the speed of light, to account for the fact that their visible light does not reach us significantly before they do.Requiring a rather contrived constraint that the older they are, the further away they are (to avoid a situation where a billion year old civilization is in e.g. the Andromeda galaxy, which should have made it visible to us within at most a few million years, so hundreds of millions years ago from the present).Why would older civilizations necessarily be more distant from us. There is no logical reason for that to be the case.The simpler alternative is that they’re just not there in the first place.The farther away we are from them, the longer it will take for them to get to us -- and the more opportunity they have to age before coming into contact with us.What would be the most likely differences in the type of "first contact" we'd experience from aliens who originate from within our solar system, as compared to aliens who originate from beyond our solar system?
Quote from: sanman on 11/25/2022 07:55 pmQuote from: M.E.T. on 11/12/2022 07:05 amGrabby aliens again. Don’t like that theory. Basically built on the assumption that because we don’t see evidence of them out there, they must be expanding fairly close to the speed of light, to account for the fact that their visible light does not reach us significantly before they do.Requiring a rather contrived constraint that the older they are, the further away they are (to avoid a situation where a billion year old civilization is in e.g. the Andromeda galaxy, which should have made it visible to us within at most a few million years, so hundreds of millions years ago from the present).Why would older civilizations necessarily be more distant from us. There is no logical reason for that to be the case.The simpler alternative is that they’re just not there in the first place.The farther away we are from them, the longer it will take for them to get to us -- and the more opportunity they have to age before coming into contact with us.What would be the most likely differences in the type of "first contact" we'd experience from aliens who originate from within our solar system, as compared to aliens who originate from beyond our solar system?The ones closer to us, if they exist, will likely be alive and the ones coming from far away will be more likely to be dead when they arrive.Space travel is never trivial, unless you go into science fictional levels of technology where you snap your fingers and a spaceship appears and you can travel close to the speed of light. But I suppose we're talking about reasonable, "known to us" means of propulsion as well as manufacturing and outfitting (i.e. no magical force fields to contain hull breaches). The longer they have to travel (just imagine sitting on top of each other for 1000 years, classes/factions are going to form, in-ship wars may be inevitable) the more likely it is that some technical failure, sabotage, uprising or other stuff happens that damages their ship and renders it uninhabitable.So, either a long distance species coming to us is extremely peaceful (towards each other and probably towards outsiders) or dead.
The ones closer to us, if they exist, will likely be alive and the ones coming from far away will be more likely to be dead when they arrive.Space travel is never trivial, unless you go into science fictional levels of technology where you snap your fingers and a spaceship appears and you can travel close to the speed of light. But I suppose we're talking about reasonable, "known to us" means of propulsion as well as manufacturing and outfitting (i.e. no magical force fields to contain hull breaches). The longer they have to travel (just imagine sitting on top of each other for 1000 years, classes/factions are going to form, in-ship wars may be inevitable) the more likely it is that some technical failure, sabotage, uprising or other stuff happens that damages their ship and renders it uninhabitable.So, either a long distance species coming to us is extremely peaceful (towards each other and probably towards outsiders) or dead.
The issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.
Our recent analysis suggests that they appear at random stars roughly once per million galaxies, and then expand at roughly half the speed of light. Right now, they have filled roughly half of the universe, and if we join them we’ll meet them in roughly a billion years. There may be far more quiet than grabby alien civs out there, but those don’t usually do much or last long, and even the ruins of the nearest are quite far away.
Quote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.From what I gather about the grabby aliens hypothesis, it is specifically designed to address the question of why humans have appeared so early in the universe's existence, 13.8 billion years in, when the average star in the universe will last ~5 trillion years and it is vastly more likely for advanced life to appear later rather than sooner by the hard-steps power law model of the origin of advanced life. It states that if we assume that human civilization is not special in appearing so early (Copernican principle and all), then there must be something that prevents civilizations like ours from appearing and observing the universe like we do in those trillions of years of distant future; that "something" is grabby aliens, which drastically change their stellar environments and prevent the emergence of indigenous alien civilizations within their sphere of influence.Because we don't observe the kind of obvious stellar engineering activity that defines "grabby aliens", the appearance rate of these types of alien civilizations is highly constrained. Robin Hanson, who proposed and wrote the mathematical model behind this hypothesis, states the following here:QuoteOur recent analysis suggests that they appear at random stars roughly once per million galaxies, and then expand at roughly half the speed of light. Right now, they have filled roughly half of the universe, and if we join them we’ll meet them in roughly a billion years. There may be far more quiet than grabby alien civs out there, but those don’t usually do much or last long, and even the ruins of the nearest are quite far away.Those are the median values that his model spits out if we assume grabby civilizations both exist and haven't appeared in our light cone yet. So it's not that "the older a civilization is, the farther away from Earth it has to be"; it's that grabby aliens in particular are so rare and expand so fast that it isn't unusual that we don't see them yet (even then, Hanson predicts that over half the universe can currently see obvious alien activity in their night skies; we're just outside those light cones at the moment). Basically, we'll encounter the nearest one in about a billion years, and in under ten billion years every star in the observable universe will be within a grabby civilization. Thus, we observe ourselves appearing near the beginning of the universe's history because civilizations like ours can only appear near the beginning; Copernican principle preserved.
Quote from: Yiosie on 11/30/2022 04:39 amQuote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.From what I gather about the grabby aliens hypothesis, it is specifically designed to address the question of why humans have appeared so early in the universe's existence, 13.8 billion years in, when the average star in the universe will last ~5 trillion years and it is vastly more likely for advanced life to appear later rather than sooner by the hard-steps power law model of the origin of advanced life. It states that if we assume that human civilization is not special in appearing so early (Copernican principle and all), then there must be something that prevents civilizations like ours from appearing and observing the universe like we do in those trillions of years of distant future; that "something" is grabby aliens, which drastically change their stellar environments and prevent the emergence of indigenous alien civilizations within their sphere of influence.Because we don't observe the kind of obvious stellar engineering activity that defines "grabby aliens", the appearance rate of these types of alien civilizations is highly constrained. Robin Hanson, who proposed and wrote the mathematical model behind this hypothesis, states the following here:QuoteOur recent analysis suggests that they appear at random stars roughly once per million galaxies, and then expand at roughly half the speed of light. Right now, they have filled roughly half of the universe, and if we join them we’ll meet them in roughly a billion years. There may be far more quiet than grabby alien civs out there, but those don’t usually do much or last long, and even the ruins of the nearest are quite far away.Those are the median values that his model spits out if we assume grabby civilizations both exist and haven't appeared in our light cone yet. So it's not that "the older a civilization is, the farther away from Earth it has to be"; it's that grabby aliens in particular are so rare and expand so fast that it isn't unusual that we don't see them yet (even then, Hanson predicts that over half the universe can currently see obvious alien activity in their night skies; we're just outside those light cones at the moment). Basically, we'll encounter the nearest one in about a billion years, and in under ten billion years every star in the observable universe will be within a grabby civilization. Thus, we observe ourselves appearing near the beginning of the universe's history because civilizations like ours can only appear near the beginning; Copernican principle preserved.All of that still means that billion year old civilizations have to be more than a billion light years away, while 100 million year old civilizations only need to be 100 million light years away. The inverse would mean that the billion year old civilization would have been visible to us for the last 900 million years or so.So yes, it does mean that older civilizations have to be farther away to make the model work.
Quote from: Slothman on 11/27/2022 04:25 pm…..snip…So, either a long distance species coming to us is extremely peaceful (towards each other and probably towards outsiders) or dead.Agree with that assessment, which incidentally simply echoes 'the meek shall inherit...'.One should also adjust for the sheer improbability of technically intelligent life, with much less than 10,000 years of existence in the at least 1 billion years of life on earth.
…..snip…So, either a long distance species coming to us is extremely peaceful (towards each other and probably towards outsiders) or dead.
I also wonder if seeing signs of highly advanced aliens is overstated. It assumes that as aliens advance, their artifacts get larger and more visible. What if it's the opposite? We see some of that right here on Earth. Compare the pile of 19th-century explosives it would have taken to completely flatten London and its environs in Queen Victoria's time with a staged thermonuclear weapon that could so the same today to the even larger London. Or compare the size and contents of the RMS Titanic's engine room, all to produce 38 MW to the Raptor 2 which fits on a forklift pallet and produces multiple GW. Or a 1950's 4-story SAGE blockhouse to a modern truck-mounted air-defense control center.As tech gets better, it gets smaller. Modern computer chips have more transistors than our brains have neurons. Nano machinery is so small that it's invisible. A truly advanced alien may be microscopic, powered by cosmic radiation and manipulating space-time directly with some kind of quantum effectors. They may move have flooded their local space with uncountable numbers of these tiny bodies and be moving their consciousnesses between them at the speed of light. If there are enough of these tiny but highly absorptive creatures out there, we may only "see" them through their net gravitational effects. They could be the explanation for dark matter.Even if that's not the case, if advanced aliens have moved their tech to the quantum scales, they could be all over the space that we see but still be invisible to us. We could be the primitives standing under the cell towers looking for the giant drums that the civilized folks signal with and wondering where they all are.
We could be the primitives standing under the cell towers looking for the giant drums that the civilized folks signal with and wondering where they all are.
*snip* The answer is simple: pollution, changes in chemistry in stars, odd IR signatures. We don't so far as I know, see any of these so far *snip*Life, of course, is everywhere - but it is highly evolved, perfectly adapted, slime.
Quote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.But the reason why the grabbies have to be farther away, is because if they weren't, then they'd likely have already grabbed us by now. The older they are, the grabbier they can be, since their engineering capabilities only grow with time, and their Von Neumann swarms have more time to grow in size and voraciousness (provided their own swarms don't swarm back at them)Why is it that "the simpler alternative is that they’re just not there in the first place" ?? Why is that simpler?Simpler that they're not there? Or simpler that they're just not grabby?
Quote from: sanman on 12/01/2022 04:17 amQuote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.But the reason why the grabbies have to be farther away, is because if they weren't, then they'd likely have already grabbed us by now. The older they are, the grabbier they can be, since their engineering capabilities only grow with time, and their Von Neumann swarms have more time to grow in size and voraciousness (provided their own swarms don't swarm back at them)Why is it that "the simpler alternative is that they’re just not there in the first place" ?? Why is that simpler?Simpler that they're not there? Or simpler that they're just not grabby?That’s a bit like arguing the reason the boogeyman has to be on Easter Island rather in New York is because if he was in New York he would have attacked us by now.EDITIf you don’t see any aliens, surely it is simpler to argue they are not there (until evidence proves otherwise), than to contrive an answer where they HAVE to be there, but they all just happen to be at a distance where their age does not allow their light to have reached us yet. There could be multiple 5 billion year old civilizations, but according to this theory they just happen to all be more than 5 billion light years away. When in reality their distribution should be random, as the Milky Way or Andromeda is just as old as galaxies 5 or 10 billion light years away.
Quote from: M.E.T. on 12/01/2022 07:56 amQuote from: sanman on 12/01/2022 04:17 amQuote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.But the reason why the grabbies have to be farther away, is because if they weren't, then they'd likely have already grabbed us by now. The older they are, the grabbier they can be, since their engineering capabilities only grow with time, and their Von Neumann swarms have more time to grow in size and voraciousness (provided their own swarms don't swarm back at them)Why is it that "the simpler alternative is that they’re just not there in the first place" ?? Why is that simpler?Simpler that they're not there? Or simpler that they're just not grabby?That’s a bit like arguing the reason the boogeyman has to be on Easter Island rather in New York is because if he was in New York he would have attacked us by now.EDITIf you don’t see any aliens, surely it is simpler to argue they are not there (until evidence proves otherwise), than to contrive an answer where they HAVE to be there, but they all just happen to be at a distance where their age does not allow their light to have reached us yet. There could be multiple 5 billion year old civilizations, but according to this theory they just happen to all be more than 5 billion light years away. When in reality their distribution should be random, as the Milky Way or Andromeda is just as old as galaxies 5 or 10 billion light years away.There's a video on YouTube from one of the co-authors of the paper proposing the grabby aliens hypothesis that shows a 3D simulation of a median scenario in their model:The first grabby alien civilizations only appear about 6 billions years after the Big Bang due to the lack of heavy elements in Population III and II stars formed in the early universe. After 13.8 billion years, the majority of the observable universe is within a grabby alien civilization, but large gaps still exist where observers would see no obvious sign of aliens in their observable universes. To your point about multiple 5 billion year old civilizations, this particular sim shows only about 8-10 existing grabby alien civs in the observable universe 5 billion years ago; if evenly distributed, their origin points would be separated by over 5 billion light years on average today, and when randomly distributed there would be smaller and large gaps. "Older civilization far, newer civilization closer" is therefore unsurprising, given how incredibly rare grabby aliens are (only 87 appear in total for this particular simulation over the 20 billion years it takes for the observable universe to be full).The grabby aliens model doesn't "contrive an answer where they HAVE to be there", it hypothesizes the existence of grabby aliens (defined as civilizations that expand quickly and radically modify stars and galaxies for their use) specifically and explicitly to explain why humans have appeared very early in the universe's history without rejecting the Copernican principle: it proposes that we aren't special, and have in fact appeared close to the end of the time in the universe when we could have possibly spawned before the universe is filled. The model then constrains the appearance rate and expansion speeds of these grabby aliens due to the fact that we don't currently observe them.Of course, everything here assumes that we are not, in fact, extremely special or unique in the timing or presence of our civilization. That we are not alone, and that we have not appeared early due to luck.
Statistical we wouldn't be first or last. There are trillions of planets out there. Life on earth has existed for few 100million years and we've gone from ape to spacefaring in 100,000years.
Quote from: Yiosie on 12/01/2022 09:54 amQuote from: M.E.T. on 12/01/2022 07:56 amQuote from: sanman on 12/01/2022 04:17 amQuote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.But the reason why the grabbies have to be farther away, is because if they weren't, then they'd likely have already grabbed us by now. The older they are, the grabbier they can be, since their engineering capabilities only grow with time, and their Von Neumann swarms have more time to grow in size and voraciousness (provided their own swarms don't swarm back at them)Why is it that "the simpler alternative is that they’re just not there in the first place" ?? Why is that simpler?Simpler that they're not there? Or simpler that they're just not grabby?That’s a bit like arguing the reason the boogeyman has to be on Easter Island rather in New York is because if he was in New York he would have attacked us by now.EDITIf you don’t see any aliens, surely it is simpler to argue they are not there (until evidence proves otherwise), than to contrive an answer where they HAVE to be there, but they all just happen to be at a distance where their age does not allow their light to have reached us yet. There could be multiple 5 billion year old civilizations, but according to this theory they just happen to all be more than 5 billion light years away. When in reality their distribution should be random, as the Milky Way or Andromeda is just as old as galaxies 5 or 10 billion light years away.There's a video on YouTube from one of the co-authors of the paper proposing the grabby aliens hypothesis that shows a 3D simulation of a median scenario in their model:The first grabby alien civilizations only appear about 6 billions years after the Big Bang due to the lack of heavy elements in Population III and II stars formed in the early universe. After 13.8 billion years, the majority of the observable universe is within a grabby alien civilization, but large gaps still exist where observers would see no obvious sign of aliens in their observable universes. To your point about multiple 5 billion year old civilizations, this particular sim shows only about 8-10 existing grabby alien civs in the observable universe 5 billion years ago; if evenly distributed, their origin points would be separated by over 5 billion light years on average today, and when randomly distributed there would be smaller and large gaps. "Older civilization far, newer civilization closer" is therefore unsurprising, given how incredibly rare grabby aliens are (only 87 appear in total for this particular simulation over the 20 billion years it takes for the observable universe to be full).The grabby aliens model doesn't "contrive an answer where they HAVE to be there", it hypothesizes the existence of grabby aliens (defined as civilizations that expand quickly and radically modify stars and galaxies for their use) specifically and explicitly to explain why humans have appeared very early in the universe's history without rejecting the Copernican principle: it proposes that we aren't special, and have in fact appeared close to the end of the time in the universe when we could have possibly spawned before the universe is filled. The model then constrains the appearance rate and expansion speeds of these grabby aliens due to the fact that we don't currently observe them.Of course, everything here assumes that we are not, in fact, extremely special or unique in the timing or presence of our civilization. That we are not alone, and that we have not appeared early due to luck.Feels similar to the probabilistic Doomsday Argument, which makes no practical sense. In this case SOMEONE had to be early. It might as well be us. It doesn’t need invisible grabby aliens to CAUSE our earliness to be normalised.Just like SOMEONE has to win the Powerball lottery draw. However improbable it might be for any specific individual.We just won the cosmic lottery. As will many others over the ensuing trillions of years of the universe’s existence. We just happen to be in the first 13.8 billion years.
Quote from: M.E.T. on 12/01/2022 02:11 pmQuote from: Yiosie on 12/01/2022 09:54 amQuote from: M.E.T. on 12/01/2022 07:56 amQuote from: sanman on 12/01/2022 04:17 amQuote from: M.E.T. on 11/30/2022 03:13 amThe issue is not about us physically meeting them. It’s about us SEEING (or rather NOT seeing) evidence of their civilizations in their home galaxies. The older they are the more visible an effect these “grabby aliens” should have on their stellar neighbourhood. To explain this lack of detection, the Grabby Alien hypothesis says that those old enough to have visibly changed their stellar environments HAVE to be far enough away that the light of their civilization has not had time to reach us yet.So a “mega structure / stellar engineering capable” civilization could have arisen 500M years ago in a galaxy 1B light years away, but it is not allowed to have arisen in the next door Andromeda galaxy more than 2.5 million years ago. Or in the Milky Way itself more than ~100K years ago. Else we would see evidence of it.So the theory requires that the older a civilization is, the farther away from Earth it has to be. That’s a weird, rather Earth-centric condition that has no logical or natural reason for existing, other than to make the theory work.But the reason why the grabbies have to be farther away, is because if they weren't, then they'd likely have already grabbed us by now. The older they are, the grabbier they can be, since their engineering capabilities only grow with time, and their Von Neumann swarms have more time to grow in size and voraciousness (provided their own swarms don't swarm back at them)Why is it that "the simpler alternative is that they’re just not there in the first place" ?? Why is that simpler?Simpler that they're not there? Or simpler that they're just not grabby?That’s a bit like arguing the reason the boogeyman has to be on Easter Island rather in New York is because if he was in New York he would have attacked us by now.EDITIf you don’t see any aliens, surely it is simpler to argue they are not there (until evidence proves otherwise), than to contrive an answer where they HAVE to be there, but they all just happen to be at a distance where their age does not allow their light to have reached us yet. There could be multiple 5 billion year old civilizations, but according to this theory they just happen to all be more than 5 billion light years away. When in reality their distribution should be random, as the Milky Way or Andromeda is just as old as galaxies 5 or 10 billion light years away.There's a video on YouTube from one of the co-authors of the paper proposing the grabby aliens hypothesis that shows a 3D simulation of a median scenario in their model:The first grabby alien civilizations only appear about 6 billions years after the Big Bang due to the lack of heavy elements in Population III and II stars formed in the early universe. After 13.8 billion years, the majority of the observable universe is within a grabby alien civilization, but large gaps still exist where observers would see no obvious sign of aliens in their observable universes. To your point about multiple 5 billion year old civilizations, this particular sim shows only about 8-10 existing grabby alien civs in the observable universe 5 billion years ago; if evenly distributed, their origin points would be separated by over 5 billion light years on average today, and when randomly distributed there would be smaller and large gaps. "Older civilization far, newer civilization closer" is therefore unsurprising, given how incredibly rare grabby aliens are (only 87 appear in total for this particular simulation over the 20 billion years it takes for the observable universe to be full).The grabby aliens model doesn't "contrive an answer where they HAVE to be there", it hypothesizes the existence of grabby aliens (defined as civilizations that expand quickly and radically modify stars and galaxies for their use) specifically and explicitly to explain why humans have appeared very early in the universe's history without rejecting the Copernican principle: it proposes that we aren't special, and have in fact appeared close to the end of the time in the universe when we could have possibly spawned before the universe is filled. The model then constrains the appearance rate and expansion speeds of these grabby aliens due to the fact that we don't currently observe them.Of course, everything here assumes that we are not, in fact, extremely special or unique in the timing or presence of our civilization. That we are not alone, and that we have not appeared early due to luck.Feels similar to the probabilistic Doomsday Argument, which makes no practical sense. In this case SOMEONE had to be early. It might as well be us. It doesn’t need invisible grabby aliens to CAUSE our earliness to be normalised.Just like SOMEONE has to win the Powerball lottery draw. However improbable it might be for any specific individual.We just won the cosmic lottery. As will many others over the ensuing trillions of years of the universe’s existence. We just happen to be in the first 13.8 billion years.I also thought of the Doomsday Argument when first reading about this, and saw that Robin Hanson had previously rejected it comprehensively. So I guess there must be some distinction between it and the grabby aliens hypothesis that I don't understand.Yes, it is very possible that we are early due to luck (that's my personal stance on the question too). Just wanted to focus the discussion back to the hypothesis that inspired the video in the first post. The authors of the paper thought that "someone has to be early, and it might as well be us" ought to be countered with an explanation rooted in the Copernican principle to consider before leaving it up to dumb luck. Their answer is "we're actually not early; we're in the middle of the distribution of emerging spacefaring civilizations", and grabby aliens is their attempt to take that possibility to a logical conclusion.In any case it was fun to put aside my own priors and explore this hypothesis here.
Quote from: TrevorMonty on 11/12/2022 07:23 amStatistical we wouldn't be first or last. There are trillions of planets out there. Life on earth has existed for few 100million years and we've gone from ape to spacefaring in 100,000years.Evolution does not have a purpose or a goal, and it does not necessarily select for complexity or intelligence. Simple / Bacterial life forms ruled the Earth for ~4 billion years. There is no particular reason, that we know of anyway, that they could not have continued to be the dominant life form for tens of billions of years. There may be trillions of planets out there with such simple life, but that does not guarantee they will eventually produce an intelligent species that creates a civilization. Even using Earth as an example, it is statistically very unlikely. We are the only one of many billions of the complex species on Earth that has developed the high level of intelligence we have. And even if a species develops intelligence, it may not have the capability or resources to produce technology. A human-intelligent dolphin could never smelt metals and build a radio, for example. Or their planet may not have a crust rich in workable metals, or they don't have any animals suitable for domestication, or crop plants that can be grown en mass with storable seeds for food during lean seasons / years. Humanity really hit the jackpot with a large amount of exploitable resources on our planet. It's also possible also that supernovae and gamma ray bursts extinguish life in large areas of the galaxy (one of the several possible Great Filters). Anyway, when I plug in my personal estimates into the Drake equation, I get maybe 5 technological civilizations in our galaxy. I don't think we are alone, but I think it may be a very long time before we find another intelligent, technology-making civilization. It is entirely possible we are the first (at least in our galaxy or in our region of the galaxy) to be able to leave our home planet.
...And even if a species develops intelligence, it may not have the capability or resources to produce technology. A human-intelligent dolphin could never smelt metals and build a radio, for example. Or their planet may not have a crust rich in workable metals, or they don't have any animals suitable for domestication, or crop plants that can be grown en mass with storable seeds for food during lean seasons / years. Humanity really hit the jackpot with a large amount of exploitable resources on our planet. ...
Quote from: whitelancer64 on 12/01/2022 02:50 pm...And even if a species develops intelligence, it may not have the capability or resources to produce technology. A human-intelligent dolphin could never smelt metals and build a radio, for example. Or their planet may not have a crust rich in workable metals, or they don't have any animals suitable for domestication, or crop plants that can be grown en mass with storable seeds for food during lean seasons / years. Humanity really hit the jackpot with a large amount of exploitable resources on our planet. ...And don't forget availability of cheap energy - fossil fuels. You can't really build industrial civilization without them (going straight from burning wood to renewable/nuclear is next to impossible). So yet another small factor to multiply the already small probabilities...
Gunpowder was invented in ancient China and resulted in no industrial revolution. …
Quote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. …It did once spread all over the old world. It took centuries for all the pieces to fit together, but again, gunpowder driven machines predated the steam powered versions by a few decades (a century or two in the case of Leonardo DiVinci writing down an idea).
Quote from: Robotbeat on 12/02/2022 03:09 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. …It did once spread all over the old world. It took centuries for all the pieces to fit together, but again, gunpowder driven machines predated the steam powered versions by a few decades (a century or two in the case of Leonardo DiVinci writing down an idea).What gunpowder driven machines?
Gunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.
Gunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.
Quote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.
Quote from: whitelancer64 on 12/02/2022 03:41 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.Not that simple. Renewables are unreliable and require large areas, nuclear although neither of those things has to overcome the problem of nuclear waste , fear of radiation leaks and not in my back yard.
Grabby aliens again. Don’t like that theory.
Quote from: daedalus1 on 12/02/2022 03:22 pmQuote from: Robotbeat on 12/02/2022 03:09 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. …It did once spread all over the old world. It took centuries for all the pieces to fit together, but again, gunpowder driven machines predated the steam powered versions by a few decades (a century or two in the case of Leonardo DiVinci writing down an idea).What gunpowder driven machines?An idea that was experimented on in the late 1600shttps://en.wikipedia.org/wiki/Gunpowder_engineFire driven steam engines were considerably easier to work with and took off shortly thereafter.
Quote from: whitelancer64 on 12/02/2022 03:41 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.Not that simple. Renewables are unreliable
and require large areas,
nuclear although neither of those things has to overcome the problem of nuclear waste , fear of radiation leaks and not in my back yard.
Quote from: whitelancer64 on 12/02/2022 03:36 pmQuote from: daedalus1 on 12/02/2022 03:22 pmQuote from: Robotbeat on 12/02/2022 03:09 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. …It did once spread all over the old world. It took centuries for all the pieces to fit together, but again, gunpowder driven machines predated the steam powered versions by a few decades (a century or two in the case of Leonardo DiVinci writing down an idea).What gunpowder driven machines?An idea that was experimented on in the late 1600shttps://en.wikipedia.org/wiki/Gunpowder_engineFire driven steam engines were considerably easier to work with and took off shortly thereafter.It wasn't a working useful machine. The earliest experimental steam engine was demonstrated 2000 years ago and I didn't count that either. The point is fossil fuels are energy dense. For the huge amount of power needed to industrialise the world, wood supplies would have run out very quickly.
Quote from: daedalus1 on 12/02/2022 03:51 pmQuote from: whitelancer64 on 12/02/2022 03:41 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.Not that simple. Renewables are unreliable That's patently untrue. Quoteand require large areas, Not all of them. Quotenuclear although neither of those things has to overcome the problem of nuclear waste , fear of radiation leaks and not in my back yard.Modern nuclear reactor designs are essentially meltdown-proof and there'd only be a radiation leak if there was a military attack on them to breach the core. Every major nuclear reactor disaster resulting in radioactive materials released has happened in reactor designs from the 1950s and 60s.
Quote from: whitelancer64 on 12/02/2022 04:08 pmQuote from: daedalus1 on 12/02/2022 03:51 pmQuote from: whitelancer64 on 12/02/2022 03:41 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.Not that simple. Renewables are unreliable That's patently untrue. Quoteand require large areas, Not all of them. Quotenuclear although neither of those things has to overcome the problem of nuclear waste , fear of radiation leaks and not in my back yard.Modern nuclear reactor designs are essentially meltdown-proof and there'd only be a radiation leak if there was a military attack on them to breach the core. Every major nuclear reactor disaster resulting in radioactive materials released has happened in reactor designs from the 1950s and 60s.You are welcome to state a compact renewable and a reliable one.Fukushima. The designs being built now are hugely expensive and typically overrun the budget massively. Why aren't lots being built and don't say fossil fuel industry, that's a cop-out. It's because of the concerns I outlined above.
Quote from: daedalus1 on 12/02/2022 04:51 pmQuote from: whitelancer64 on 12/02/2022 04:08 pmQuote from: daedalus1 on 12/02/2022 03:51 pmQuote from: whitelancer64 on 12/02/2022 03:41 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. Wood has been around a long time.The use of the dense power of fossil fuel was crucial to the industrial revolution and still society is finding it difficult to replace them.We could transition to 100% sustainable power (especially nuclear) over the course of a few decades, if we, as a whole, made it a priority to do so. The main difficulty is, as it has been for decades, the political power of the fossil fuel industry blocking any such efforts.Not that simple. Renewables are unreliable That's patently untrue. Quoteand require large areas, Not all of them. Quotenuclear although neither of those things has to overcome the problem of nuclear waste , fear of radiation leaks and not in my back yard.Modern nuclear reactor designs are essentially meltdown-proof and there'd only be a radiation leak if there was a military attack on them to breach the core. Every major nuclear reactor disaster resulting in radioactive materials released has happened in reactor designs from the 1950s and 60s.You are welcome to state a compact renewable and a reliable one.Fukushima. The designs being built now are hugely expensive and typically overrun the budget massively. Why aren't lots being built and don't say fossil fuel industry, that's a cop-out. It's because of the concerns I outlined above.Hydropower, solar, and wind are all very reliable. By the way, they currently generate about 30% of the global supply of electricity. The reactors at the Fukushima power plant were designed in the 60s, the construction of the facility was started in 1971. Cost overruns would be far less of an issue if they were being built en masse, instead of as one-off builds. This is also largely a US problem, other countries that build nuclear power plants on a more regular basis don't see such issues. Why aren't lots being built is because lots of people are dumb and are scared of nuclear power. We should ignore them and just build lots of nuclear power plants.
Quote from: TrevorMonty on 11/12/2022 07:23 amStatistical we wouldn't be first or last. There are trillions of planets out there. Life on earth has existed for few 100million years and we've gone from ape to spacefaring in 100,000years.My argument here is the same as it has been in the many other similar threads on this topic. Evolution does not have a purpose or a goal, and it does not necessarily select for complexity or intelligence. Simple / Bacterial life forms ruled the Earth for ~4 billion years. There is no particular reason, that we know of anyway, that they could not have continued to be the dominant life form for tens of billions of years.There may be trillions of planets out there with such simple life, but that does not guarantee they will eventually produce an intelligent species that creates a civilization. Even using Earth as an example, it is statistically very unlikely. We are the only one of many billions of the complex species on Earth that has developed the high level of intelligence we have.
And even if a species develops intelligence, it may not have the capability or resources to produce technology. A human-intelligent dolphin could never smelt metals and build a radio, for example. Or their planet may not have a crust rich in workable metals, or they don't have any animals suitable for domestication, or crop plants that can be grown en mass with storable seeds for food during lean seasons / years. Humanity really hit the jackpot with a large amount of exploitable resources on our planet.
It's also possible also that supernovae and gamma ray bursts extinguish life in large areas of the galaxy (one of the several possible Great Filters).
Anyway, when I plug in my personal estimates into the Drake equation, I get maybe 5 technological civilizations in our galaxy. I don't think we are alone, but I think it may be a very long time before we find another intelligent, technology-making civilization. It is entirely possible we are the first (at least in our galaxy or in our region of the galaxy) to be able to leave our home planet.
Quote from: M.E.T. on 11/12/2022 07:05 amGrabby aliens again. Don’t like that theory.Dunno what "grabby" aliens are, but let me dust off my "3 Civilizations Conjecture". [3CC]There are three civilizations in the universe; the ones who achieved sentience the day before mankind did, us, and the ones who achieved sentience the day after we did. We all have about the same tech, and cannot see each other because we're so widely dispersed.
Quote from: whitelancer64 on 12/02/2022 06:07 pmHydropower, solar, and wind are all very reliable. By the way, they currently generate about 30% of the global supply of electricity. The reactors at the Fukushima power plant were designed in the 60s, the construction of the facility was started in 1971. Cost overruns would be far less of an issue if they were being built en masse, instead of as one-off builds. This is also largely a US problem, other countries that build nuclear power plants on a more regular basis don't see such issues. Why aren't lots being built is because lots of people are dumb and are scared of nuclear power. We should ignore them and just build lots of nuclear power plants.Hydropower doesn't work in a drought, solar doesn't work at night, wind doesn't work when the wind stops.All of them take up a large area compared to the wattage output.By the way Germany just dug up a wind farm to get to the fossil fuel coal underneath it.
Hydropower, solar, and wind are all very reliable. By the way, they currently generate about 30% of the global supply of electricity. The reactors at the Fukushima power plant were designed in the 60s, the construction of the facility was started in 1971. Cost overruns would be far less of an issue if they were being built en masse, instead of as one-off builds. This is also largely a US problem, other countries that build nuclear power plants on a more regular basis don't see such issues. Why aren't lots being built is because lots of people are dumb and are scared of nuclear power. We should ignore them and just build lots of nuclear power plants.
Quote from: whitelancer64 on 12/01/2022 02:50 pmQuote from: TrevorMonty on 11/12/2022 07:23 amStatistical we wouldn't be first or last. There are trillions of planets out there. Life on earth has existed for few 100million years and we've gone from ape to spacefaring in 100,000years.My argument here is the same as it has been in the many other similar threads on this topic. Evolution does not have a purpose or a goal, and it does not necessarily select for complexity or intelligence. Simple / Bacterial life forms ruled the Earth for ~4 billion years. There is no particular reason, that we know of anyway, that they could not have continued to be the dominant life form for tens of billions of years.There may be trillions of planets out there with such simple life, but that does not guarantee they will eventually produce an intelligent species that creates a civilization. Even using Earth as an example, it is statistically very unlikely. We are the only one of many billions of the complex species on Earth that has developed the high level of intelligence we have.Darwinism promotes dominance, because in the survival of the fittest, the dominant prevail. Clearly intelligence would be an eventual outcome of that, since intelligence helps dominance. We don't see bacteria actively seeking ways to become multiplanetary, like we humans are doing. It's just that it takes time for Darwinism to do its work, and evolve organisms up to our level.
QuoteAnd even if a species develops intelligence, it may not have the capability or resources to produce technology. A human-intelligent dolphin could never smelt metals and build a radio, for example. Or their planet may not have a crust rich in workable metals, or they don't have any animals suitable for domestication, or crop plants that can be grown en mass with storable seeds for food during lean seasons / years. Humanity really hit the jackpot with a large amount of exploitable resources on our planet.Intelligence finds a way, because of what we like to call "the human condition", which may in fact just be "the intelligent condition". All human (read: intelligent) beings seek to have their cake and eat it too - that means trying to get more work done with less effort, and all that. Which means developing tools, instruments, and all the rest. Just like everything else in the universe, we living things seek conserve our energy.
QuoteIt's also possible also that supernovae and gamma ray bursts extinguish life in large areas of the galaxy (one of the several possible Great Filters).These are random uncorrelated random events which can indeed strike down the evolved through no fault of their own. Although, just like humans striving to develop planetary defense against asteroids, one could imagine sufficiently advanced civilizations surveying for these even larger astrophysical phenomena to guard against them as well.QuoteAnyway, when I plug in my personal estimates into the Drake equation, I get maybe 5 technological civilizations in our galaxy. I don't think we are alone, but I think it may be a very long time before we find another intelligent, technology-making civilization. It is entirely possible we are the first (at least in our galaxy or in our region of the galaxy) to be able to leave our home planet.We are living in a very small timeslice of our overall evolutionary history, and if we succeed in becoming multiplanetary or even interstellar, then our evolutionary history could extend for a lot longer. If we continue on for long enough, we may eventually come upon signs of other technological civilizations, who could quickly pop up out of nowhere.But is it more prudent for us to try to detect them before allowing them to detect us first?
All these discussions about extraterrestrial civilizations ultimately go back to relying on the Fermi paradox, which is based on a simple fallacy. It assumes that once a civilization becomes spacefaring, it will choose to focus on finding other planets to exploit and/or colonize.I don't think this is a compelling assumption..
Asteroids will for some time be the primary sources for wealth accumulation in the solar system: they are relatively undifferentiated, valuable elements are not sequestered in difficult to reach locations...
Quote from: llanitedave on 12/24/2022 04:00 amAsteroids will for some time be the primary sources for wealth accumulation in the solar system: they are relatively undifferentiated, valuable elements are not sequestered in difficult to reach locations...Asteroids are not in "difficult to reach locations"?That's good to know.
Quote from: llanitedave on 12/24/2022 04:00 amAll these discussions about extraterrestrial civilizations ultimately go back to relying on the Fermi paradox, which is based on a simple fallacy. It assumes that once a civilization becomes spacefaring, it will choose to focus on finding other planets to exploit and/or colonize.I don't think this is a compelling assumption..This is incorrect: actually, you just mentioned one of the many hypotesized solutions to the Fermi Paradox, that as such - a "paradox" - can't contain a fallacy.
Quote from: gdelottle on 12/26/2022 02:03 pmQuote from: llanitedave on 12/24/2022 04:00 amAll these discussions about extraterrestrial civilizations ultimately go back to relying on the Fermi paradox, which is based on a simple fallacy. It assumes that once a civilization becomes spacefaring, it will choose to focus on finding other planets to exploit and/or colonize.I don't think this is a compelling assumption..This is incorrect: actually, you just mentioned one of the many hypotesized solutions to the Fermi Paradox, that as such - a "paradox" - can't contain a fallacy.The fallacy is in thinking of it as a paradox at all. If it has plausible solutions, it's not a paradox.
Quote from: JohnFornaro on 12/26/2022 02:30 pmQuote from: llanitedave on 12/24/2022 04:00 amAsteroids ... are not sequestered in difficult to reach locations...Asteroids are not in "difficult to reach locations"?That's good to know.Compared to planets, no. I'm not talking about our current state of technology, this thread references "spacefaring civilizations." For a civilization that is capable of being spacefaring, asteroids are easy.
Quote from: llanitedave on 12/24/2022 04:00 amAsteroids ... are not sequestered in difficult to reach locations...Asteroids are not in "difficult to reach locations"?That's good to know.
Asteroids ... are not sequestered in difficult to reach locations...
Quote from: JohnFornaro on 12/02/2022 03:56 pmDunno what "grabby" aliens are, but let me dust off my "3 Civilizations Conjecture". [3CC]There are three civilizations in the universe; the ones who achieved sentience the day before mankind did, us, and the ones who achieved sentience the day after we did. We all have about the same tech, and cannot see each other because we're so widely dispersed.But are you taking into account the idea that there are those who achieve sentience and civilization after we do, but whose pace of advancement was fast enough to overtake us? Likewise, there could be those who achieved sentience and civilization before we did, and their pace of advancement was slow enough for us to overtake them.Maybe there's some other Earth out there that didn't have an asteroid impact like the one that killed off our dinosaurs. So they got to evolve farther much sooner, without suffering as many setbacks. Or is it maybe because we suffered an asteroid extinction event, [AEE] that we got to evolve to higher levels of intelligence sooner?
Dunno what "grabby" aliens are, but let me dust off my "3 Civilizations Conjecture". [3CC]There are three civilizations in the universe; the ones who achieved sentience the day before mankind did, us, and the ones who achieved sentience the day after we did. We all have about the same tech, and cannot see each other because we're so widely dispersed.
Quote from: daedalus1 on 12/02/2022 03:22 pmQuote from: Robotbeat on 12/02/2022 03:09 pmQuote from: daedalus1 on 12/02/2022 02:40 pmGunpowder was invented in ancient China and resulted in no industrial revolution. …It did once spread all over the old world. It took centuries for all the pieces to fit together, but again, gunpowder driven machines predated the steam powered versions by a few decades (a century or two in the case of Leonardo DiVinci writing down an idea).What gunpowder driven machines?Um, cannons?
Cannons are simple gunpowder driven machines. People had the idea of replacing the cannonball with a piston (or just creating a vacuum), using gunpowder sequentially, and using this to pump water or drive machinery. This concept predated the steam driven Savery pump patented in 1698.https://en.wikipedia.org/wiki/Gunpowder_engineHuygens and Papin did experiments to this effect in the 1670s, and an invention for using gunpowder to pump water appeared as early as Samuel Morland’s 1661 invention.Hooke also mentioned the idea in the 1670s. Da Vinci mentioned the idea in 1508.
Quote from: Robotbeat on 12/28/2022 01:03 pmCannons are simple gunpowder driven machines. People had the idea of replacing the cannonball with a piston (or just creating a vacuum), using gunpowder sequentially, and using this to pump water or drive machinery. This concept predated the steam driven Savery pump patented in 1698.https://en.wikipedia.org/wiki/Gunpowder_engineHuygens and Papin did experiments to this effect in the 1670s, and an invention for using gunpowder to pump water appeared as early as Samuel Morland’s 1661 invention.Hooke also mentioned the idea in the 1670s. Da Vinci mentioned the idea in 1508.Did someone use one to do actual productive work?
Quote from: daedalus1 on 12/28/2022 01:36 pmQuote from: Robotbeat on 12/28/2022 01:03 pmCannons are simple gunpowder driven machines. People had the idea of replacing the cannonball with a piston (or just creating a vacuum), using gunpowder sequentially, and using this to pump water or drive machinery. This concept predated the steam driven Savery pump patented in 1698.https://en.wikipedia.org/wiki/Gunpowder_engineHuygens and Papin did experiments to this effect in the 1670s, and an invention for using gunpowder to pump water appeared as early as Samuel Morland’s 1661 invention.Hooke also mentioned the idea in the 1670s. Da Vinci mentioned the idea in 1508.Did someone use one to do actual productive work?Other than weapons, not that I’m aware of, but that’s irrelevant. The ideas developed by the development of gunpowder and experiments with it directly led to steam power, which was much more practical (as wood & coal are much cheaper than gunpowder).Using fire to do physical work is THE principle, and it started with the first gunpowder weapons which launched projectiles.
Of course, before even being used for true cannons, gunpowder was used for rockets…
In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled.
I'd agree with this but after billions of years to present-day, you have to think there has emerged at least one giga-powerful, almighty planet-eating civilization.
If our physics is wrong, and I think it is, FTL is possible and other Civs would have found it eventually. But we have no evidence they are here but they should be here or have been here.
In fact, what the meteorites studies tell us is that we can even make a bolder prediction: On Mars (or elsewhere), if carbon processing life exists, then L-alanine will perform better than D-alanine in a labeled release experiment. Hopefully, repeating this experiment in its chiral modification will be considered for a future mission. No doubt, a new fascinating era of the exploration of life beyond Earth has just begun.
Quote from: dondar on 11/24/2022 11:58 amgood example of why American habit of early specialization in .... sucks.I don't understand what you mean by this, Please explain.
Quote from: arfdog on 03/07/2023 08:52 pmI'd agree with this but after billions of years to present-day, you have to think there has emerged at least one giga-powerful, almighty planet-eating civilization.That assumes that planets are particularly attractive to inter-stellar spacefarers. It may be that rocks stock in a big ball at the bottom of a gravity well - requiring you to start stripping away at the surface just to get at the juicy bits - just aren't all that useful when you can pick systems to visit with more attractive combinations of loose rubble orbiting hot stars (more energy available, less energy needed to access resources). "Aliens want to invade our planet" seems like a mere extension of the old "aliens want to steal out water" trope that ignores the teratonnes of water available floating about the rest of the solar system alone that does not require ~11km/s to drag out of a gravity well.
Thoughts: Universe 13.5 Billion years old. Sun 4.5B, Earth 4B, Life 3.8B, Humanoid 2M, Civ 15k, radio 130yrs ago, nukes 70 years ago, Spacefaring 60yrs ago, Intrasolar TBD. Interstellar TBD. Max Civ on Earth lifespan remaining, 1B years. Sun's remaining lifespan 5B. That is basically 4.5B of nothing and 1 Billion year window to GTFO. What were the previous 9B years of the Universe like? They might need stable stars that exist 5B years before Space Civs arise. Large stars die quickly. Most stable stars have planets but we don't know what percentage are in the habitable/water zone. Could be very rare. If Aliens existed and could leave their planet they would know of Earth, but either cannot get here since too far and FTL is impossible or Earth had no detectable Civs before they died out. If FTL is possible they would have been on Earth, ignored us or conquered US or had non-interference, stealth observe or colonized Earth. I think advanced civs are very rare. Maybe less than 100 per Galaxy over 10B years. FTL is the key. If our physics is basically correct FTL is not possible. No one ever goes very far, even over billions of years. If our physics is wrong, and I think it is, FTL is possible and other Civs would have found it eventually. But we have no evidence they are here but they should be here or have been here. I think most of these puzzles will be solved in the next 50 years.
And I doubt we'll ever be able to visit each other, furthermore I doubt anyone will figure out FTL travel.... seeing as no other phenomena or entity in the universe seems to have achieved this.
... all of us having just emerged from single-celled organisms recently.
*snip*Most stable stars have planets but we don't know what percentage are in the habitable/water zone. Could be very rare. *snip*
*snip*FTL is the key. If our physics is basically correct FTL is not possible. No one ever goes very far, even over billions of years. *snip*
Quote from: GalacticIntruder on 03/08/2023 07:56 am*snip*Most stable stars have planets but we don't know what percentage are in the habitable/water zone. Could be very rare. *snip*NASA's analysis of the Kepler space telescope data, shows that about half of all Sun-like stars could have a rocky planet in the habitable zone. The most conservative estimate in that study is 7% of all Sun-like stars in our galaxy should have a rocky planet in the habitable zone. This would mean there is approximately 300 million such planets in the Milky Way galaxy. https://www.nasa.gov/feature/ames/kepler-occurrence-rate
Quote from: whitelancer64 on 03/15/2023 06:33 pmQuote from: GalacticIntruder on 03/08/2023 07:56 am*snip*Most stable stars have planets but we don't know what percentage are in the habitable/water zone. Could be very rare. *snip*NASA's analysis of the Kepler space telescope data, shows that about half of all Sun-like stars could have a rocky planet in the habitable zone. The most conservative estimate in that study is 7% of all Sun-like stars in our galaxy should have a rocky planet in the habitable zone. This would mean there is approximately 300 million such planets in the Milky Way galaxy. https://www.nasa.gov/feature/ames/kepler-occurrence-rateI'd say one of the biggest unknowns about the prevalence and complexity of life in the universe is how critical and unique the Theia collision event was to life's development on Earth. If complex life could not have arisen without it, 300 million starts to sound like an awfully tiny number.
While there are alot of rocky planets out there, rocky does not equal habitable. There is alot of thought that planets close in to a m star will not have an atmosphere. To date, we've gotten info about atmospheres for a tiny number of rocky planets around m stars, and they've had no atmosphere. JWST found one didn't have an atmosphere recently. The idea that theres lots of planets, so it must've happened lots of chances misses a basic idea of statistics. That assumes that life is common, and that intelligent tool using life is rather common. Whats uncommon? People often run through the drake equation and use 1/10 chances or 1/100 for each step. What if the chance of life is 1 in a trillion? What of life developing tools is 1 in quintillion? That would mean we are the only ones in the entire super cluster. However people rarely consider numbers like that because it:1. gives results they don't life2. don't normally deal wiht numbers like that, so they are inherantly biased against considering them.Remember that aside from number of rocky planets, ALL the statistics people use are 100% made up with zero basis in fact. We simply don't have the information to make these predictions.