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It has always seemed arrogant to think that aliens exist anywhere within our galaxy. Look at how many galaxies are out there. Now realize that the universe exte

by shawn 8y ago

It has always seemed arrogant to think that aliens exist anywhere within our galaxy. Look at how many galaxies are out there. Now realize that the universe extends far beyond our Hubble sphere. We can’t hope to colonize even a fraction of 1% of our galaxy, even with wildly futuristic technology. There is one option, though: Become our own aliens. If we set up colonies separated by time and distance, we will culturally diverge within a century, and genetically within a few millennia-ish.

Cthulhu_ 8y ago
What if we are the aliens though?
- ballade 8y ago
  Panspermia?
  - mirimir 8y ago
    Maybe, but not necessarily even that. The flow of chemical evolution that leads to carbon-based life is just so highly likely. We see some key molecules just about everywhere we look out there. And various simulations (physical, not virtual) create nucleic acids, amino acids, fatty acids, carbohydrates, etc. So there's no reason to think that the Earth is special.
    - pbhjpbhj 8y ago
      Something I don't get, people say something along those lines -- that with earth-like conditions, blah-blah, earth-like planets, ... then life! But also experts claim life only arose once on Earth. So, in a place with perfect conditions, the perfect distance from the sun, the perfect atmosphere, perfect trigger, perfect environmental conditions, life only started once! Doesn't that make it so infinitesimally unlikely that even with millions, billions, of planets with the right conditions we still shouldn't expect abiogenesis to occur. The same arguments that make for extraterrestrial life surely stand against the uniqueness of anything. We know things that are unique. Seems like it's mostly faith based assertion.
      - nervousvarun 8y ago
        Just curious how can anyone conclusively claim life arose only once? Don't they just say we only have evidence that it arose once? Maybe it started twice or 100M times but 100% of those times the newly started life was "consumed" in some way by already existing life etc.
        mirimir 8y ago
        Yes, that seems a dubious claim. There's no way to know, except though simulations, how many dead ends there were. What we know is that all existing organisms share basic biochemical features. More or less the same nucleic acids, amino acids, and so on. So other paths arguably got competed out. Or merged, as we know for nuclei, mitochondria and chloroplasts in eukaryotes. Probably also components of bacteria. Flagella, maybe? The whole DNA/RNA/protein thing could well be a kludge. The especially cool aspect of searching for life elsewhere in the solar system is the possibility that we'll find other variants that dominated.
        jobigoud 8y ago
        It's also because we have tried all sorts of approaches for the past 70 years or so and we haven't been able to bootstrap it ourselves.
        mirimir 8y ago
        I doubt that any of the experiments have run for longer than a few years. And probably less.
      - burlesona 8y ago
        Or an anti-faith based assertion. It’s in many ways much more terrifying if we are, in fact, special. If we are just one of billions of places that life is going strong then we’ll do the best we can but if we don’t survive the eons who cares. If Earth is the one and only seed of life, then don’t we have an incredible moral imperative not to wreck things here, and if possible to spread life into the darkness? Being truly alone in the vast dark is a much scarier idea to live with.
adrianN 8y ago
Von Neumann probes could probably colonize a good chunk of the Milky Way given a few hundred thousand years.
- ghaff 8y ago
  That in turn makes assumptions about the practicality of interstellar travel etc. But, yes. The counterpoint to space is big is that so are timescales.
  - adrianN 8y ago
    Interstellar travel is definitely possible. The only question is how long the trips take. You can build nuclear pulse propulsion vessels fairly easily that can reach a few percent of the speed of light. Those things can cross the Milky Way in less than ten million years.
    - ghaff 8y ago
      I wouldn't use the term "definitely." But it looks like "just" a (very hard) engineering problem [i.e. no known fundamental reasons why it's impossible]. And humans are pretty good at solving engineering problems over relatively short periods of time. ADDED: There are also questions of resources, motivations, and e.g. whether we'd even want to build self-replicating probes.
      - adrianN 8y ago
        No, speed is the hard engineering problem. The Voyager probes for example have reached escape velocity from our solar system. That's fairly primitive rocket technology.
  - bramgn 8y ago
    This. I always wonder why discussions about the search for alien civilizations don't take the massive timescale more into consideration. Say you're watching a summary of our universe compressed to a hundred years. Each time a civilization pops up, it might just hold on long enough to last a nanosecond. We're just living that in that blip of a time.
OscarCunningham 8y ago
>We can’t hope to colonize even a fraction of 1% of our galaxy, even with wildly futuristic technology. If you can do any colonization at all it shouldn't be that much harder to colonize the whole galaxy. Once you've got the ability to colonize exponential growth will take over and pretty soon* you'll be everywhere. *In the context of the Fermi paradox, we're wondering why no aliens have already colonized the galaxy (including our solar system). So by "pretty soon" I mean relative to the time interval between when such aliens might have appeared and now.
- jcranmer 8y ago
  There is a basic epistemological flaw that goes on in the Fermi Paradox (and similar arguments): the argument rests on the idea that, given enough time, an event which has non-zero probability will eventually happen. The flaw is that there is no consideration of if enough time has actually passed, since the probabilities we talk about are often characterized on the level of "we don't conclusively know it to be impossible." If you look at the statement you yourself make, it requires a lot of assumptions: * Interstellar colonization is possible (this is explicitly taken as a hypothesis, though) * The ability to colonize another star system is the ability to colonize a large number of star systems. This is to say, the social consequences of colonization are not going to grow larger with size. A possible counterfactual would be that large civilizations might put more energy into securing control of known systems rather than embarking on further colonization--and the anecdotal evidence from the history of Earth is that this is indeed the case. * Colonization is a logistic process (which is probably what you really meant when you said exponential, but the difference is a technicality for this discussion). If interstellar travel is really as difficult as our knowledge of physics suggests it to be, then interstellar colonies are likely to develop as completely independent civilizations without maintaining strong ties to their parent motherlands, and subsequent colonization efforts are going to include attempts to "colonize" already-colonized systems and consequently logistic growth wouldn't be achieved.
- pfdietz 8y ago
  We're also wondering why we haven't seen any other galaxy that's been fully colonized and industrialized. K3 civilizations would be detectable at cosmological distances.

by shawn 8y ago

Cthulhu_ 8y ago

What if we are the aliens though?

ballade 8y ago
Panspermia?
- mirimir 8y ago
  Maybe, but not necessarily even that. The flow of chemical evolution that leads to carbon-based life is just so highly likely. We see some key molecules just about everywhere we look out there. And various simulations (physical, not virtual) create nucleic acids, amino acids, fatty acids, carbohydrates, etc. So there's no reason to think that the Earth is special.
  - pbhjpbhj 8y ago
    Something I don't get, people say something along those lines -- that with earth-like conditions, blah-blah, earth-like planets, ... then life! But also experts claim life only arose once on Earth. So, in a place with perfect conditions, the perfect distance from the sun, the perfect atmosphere, perfect trigger, perfect environmental conditions, life only started once! Doesn't that make it so infinitesimally unlikely that even with millions, billions, of planets with the right conditions we still shouldn't expect abiogenesis to occur. The same arguments that make for extraterrestrial life surely stand against the uniqueness of anything. We know things that are unique. Seems like it's mostly faith based assertion.
    - nervousvarun 8y ago
      Just curious how can anyone conclusively claim life arose only once? Don't they just say we only have evidence that it arose once? Maybe it started twice or 100M times but 100% of those times the newly started life was "consumed" in some way by already existing life etc.
      - mirimir 8y ago
        Yes, that seems a dubious claim. There's no way to know, except though simulations, how many dead ends there were. What we know is that all existing organisms share basic biochemical features. More or less the same nucleic acids, amino acids, and so on. So other paths arguably got competed out. Or merged, as we know for nuclei, mitochondria and chloroplasts in eukaryotes. Probably also components of bacteria. Flagella, maybe? The whole DNA/RNA/protein thing could well be a kludge. The especially cool aspect of searching for life elsewhere in the solar system is the possibility that we'll find other variants that dominated.
        jobigoud 8y ago
        It's also because we have tried all sorts of approaches for the past 70 years or so and we haven't been able to bootstrap it ourselves.
        mirimir 8y ago
        I doubt that any of the experiments have run for longer than a few years. And probably less.
    - burlesona 8y ago
      Or an anti-faith based assertion. It’s in many ways much more terrifying if we are, in fact, special. If we are just one of billions of places that life is going strong then we’ll do the best we can but if we don’t survive the eons who cares. If Earth is the one and only seed of life, then don’t we have an incredible moral imperative not to wreck things here, and if possible to spread life into the darkness? Being truly alone in the vast dark is a much scarier idea to live with.

adrianN 8y ago

Von Neumann probes could probably colonize a good chunk of the Milky Way given a few hundred thousand years.

ghaff 8y ago
That in turn makes assumptions about the practicality of interstellar travel etc. But, yes. The counterpoint to space is big is that so are timescales.
- adrianN 8y ago
  Interstellar travel is definitely possible. The only question is how long the trips take. You can build nuclear pulse propulsion vessels fairly easily that can reach a few percent of the speed of light. Those things can cross the Milky Way in less than ten million years.
  - ghaff 8y ago
    I wouldn't use the term "definitely." But it looks like "just" a (very hard) engineering problem [i.e. no known fundamental reasons why it's impossible]. And humans are pretty good at solving engineering problems over relatively short periods of time. ADDED: There are also questions of resources, motivations, and e.g. whether we'd even want to build self-replicating probes.
    - adrianN 8y ago
      No, speed is the hard engineering problem. The Voyager probes for example have reached escape velocity from our solar system. That's fairly primitive rocket technology.
- bramgn 8y ago
  This. I always wonder why discussions about the search for alien civilizations don't take the massive timescale more into consideration. Say you're watching a summary of our universe compressed to a hundred years. Each time a civilization pops up, it might just hold on long enough to last a nanosecond. We're just living that in that blip of a time.

OscarCunningham 8y ago

>We can’t hope to colonize even a fraction of 1% of our galaxy, even with wildly futuristic technology. If you can do any colonization at all it shouldn't be that much harder to colonize the whole galaxy. Once you've got the ability to colonize exponential growth will take over and pretty soon* you'll be everywhere. *In the context of the Fermi paradox, we're wondering why no aliens have already colonized the galaxy (including our solar system). So by "pretty soon" I mean relative to the time interval between when such aliens might have appeared and now.

jcranmer 8y ago
There is a basic epistemological flaw that goes on in the Fermi Paradox (and similar arguments): the argument rests on the idea that, given enough time, an event which has non-zero probability will eventually happen. The flaw is that there is no consideration of if enough time has actually passed, since the probabilities we talk about are often characterized on the level of "we don't conclusively know it to be impossible." If you look at the statement you yourself make, it requires a lot of assumptions: * Interstellar colonization is possible (this is explicitly taken as a hypothesis, though) * The ability to colonize another star system is the ability to colonize a large number of star systems. This is to say, the social consequences of colonization are not going to grow larger with size. A possible counterfactual would be that large civilizations might put more energy into securing control of known systems rather than embarking on further colonization--and the anecdotal evidence from the history of Earth is that this is indeed the case. * Colonization is a logistic process (which is probably what you really meant when you said exponential, but the difference is a technicality for this discussion). If interstellar travel is really as difficult as our knowledge of physics suggests it to be, then interstellar colonies are likely to develop as completely independent civilizations without maintaining strong ties to their parent motherlands, and subsequent colonization efforts are going to include attempts to "colonize" already-colonized systems and consequently logistic growth wouldn't be achieved.
pfdietz 8y ago
We're also wondering why we haven't seen any other galaxy that's been fully colonized and industrialized. K3 civilizations would be detectable at cosmological distances.