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The Drake equations are the most convincing assessment of where we’re at and why that I’ve read — upshot, the fact that nobody is near us is a GREAT sign that w

The Drake equations are the most convincing assessment of where we’re at and why that I’ve read — upshot, the fact that nobody is near us is a GREAT sign that we’re likely going to have time to expand out of our solar system before some dominant civ just eats us maybe without even noticing us. That said, so many of these ‘intelligent life’ things have so many baked in assumptions, I’m constantly frustrated: “Must be water based, since that’s what we know,” “Must communicate via radio like we do in ways that we could recognize”, … The assumptions are legion.

VagabundoP 2y ago
Exactly, there’s alien and there’s alien alien. We can’t even imagine alien alien.
bsder 2y ago
> “Must be water based, since that’s what we know,” This one is an assumption, but it's a pretty good one. Equilibrium chemistry has a fairly narrow band of energy in which things can be pushed to one side or the other without completely dissociating. A solvent is almost always required as a medium and water is about as "simple" as that gets. Sub-zero chemistries might work, but they would be much slower than water--life might take longer than the age of the universe to evolve. Molten chemistries don't seem to be able to hang together long enough to be reversible. While the "building blocks" of life might be different, given our current knowledge of physics, the probability that the solvent for life is water is likely very high.
- vundercind 2y ago
  Chemistry’s the limiting factor for most of it. You’ll need a lot of energy for complex life. The list of things that can naturally provide enough without having extremely-hostile side effects is pretty much limited to stars, and then only if you get really lucky in a whole bunch of ways. Then you need to turn that into chemical energy to actually do anything with it. That’s gonna turn useful chemicals from the environment into waste you can no longer use. If you’re lucky the waste is chemically useful, and if something can evolve to use it, maybe it can turn it back into what you need (happened with oxygen). If the waste isn’t useful, you better hope your planet’s recycling it somehow. Ideally with some kind system that adjusts with a feedback-loop so it doesn’t limit your growth too much. Our one example sure looks extremely fragile, in that if you mess with any of several things a little bit, you might still get life, but it’ll cyclically wipe itself out, or never be able to harvest enough energy to support complex life, or any number of other problems that end in not seeing intelligence arise.
  - aaronblohowiak 2y ago
    Are we after the great filter?
poikroequ 2y ago
> However, it should be noted that the Drake equation is more of a thought experiment to highlight what we know and what we don't know about the evolution of technological life, rather than an absolute guide to the number of civilizations out there. I fully agree with your second paragraph though.
Beijinger 2y ago
"is a GREAT sign that we’re likely going to have time to expand out of our solar system before some dominant civ just eats us maybe without even noticing us." This is a bold interpretation. Could be a sign of many things. Like that life is much rarer than we assume. Could be that all civilizations run into some kind of energy trap or that civilizations tend to destroy themself with technology “Must be water based, since that’s what we know,” No scientist says that they MUST be water based, but water based would be a decent assumption since we know life can be water based. To look for life in general: look for entropy sources. https://www.sciencealert.com/entropy-could-be-the-secret-to-alien-worlds-being-habitable https://www.sciencealert.com/entropy-could-be-the-secret-to-...
- vessenes 2y ago
  I think your possible scenarios -- very rare life, energy trap or great winnower / cliff -- actually are all pretty positive in terms of Drake - to me the major point the equations make is just this: if you see any aliens at all, it is likely that you are late to the game of getting extrasolar, and due to the timescales involved, it is most likely that you are very very late to the game. That said, if, say in a billion years, we survive as a race, and still haven't met anyone, then some of those drake choices are very different than we imagine them -- and we must have somehow gotten really lucky, or there is something else very strange going on. Regardless, it would likely be pretty bad news to a single-planet lifeform to meet us at that point, or at least tectonic, depending on how altruistic society as a whole would be at the time of the meeting.
raxxorraxor 2y ago
I would think radio waves to be quite sensible here compared to other-dimensional ghost-aliens roaming the skies. Given radio waves being the primary marker for our own existence and looking at the distance those artificial signals already travelled compared to the size of the cosmos, I believe not having any form of indication for intelligent or any alien life is a surprise.

VagabundoP 2y ago

Exactly, there’s alien and there’s alien alien. We can’t even imagine alien alien.

bsder 2y ago

> “Must be water based, since that’s what we know,” This one is an assumption, but it's a pretty good one. Equilibrium chemistry has a fairly narrow band of energy in which things can be pushed to one side or the other without completely dissociating. A solvent is almost always required as a medium and water is about as "simple" as that gets. Sub-zero chemistries might work, but they would be much slower than water--life might take longer than the age of the universe to evolve. Molten chemistries don't seem to be able to hang together long enough to be reversible. While the "building blocks" of life might be different, given our current knowledge of physics, the probability that the solvent for life is water is likely very high.

vundercind 2y ago
Chemistry’s the limiting factor for most of it. You’ll need a lot of energy for complex life. The list of things that can naturally provide enough without having extremely-hostile side effects is pretty much limited to stars, and then only if you get really lucky in a whole bunch of ways. Then you need to turn that into chemical energy to actually do anything with it. That’s gonna turn useful chemicals from the environment into waste you can no longer use. If you’re lucky the waste is chemically useful, and if something can evolve to use it, maybe it can turn it back into what you need (happened with oxygen). If the waste isn’t useful, you better hope your planet’s recycling it somehow. Ideally with some kind system that adjusts with a feedback-loop so it doesn’t limit your growth too much. Our one example sure looks extremely fragile, in that if you mess with any of several things a little bit, you might still get life, but it’ll cyclically wipe itself out, or never be able to harvest enough energy to support complex life, or any number of other problems that end in not seeing intelligence arise.
- aaronblohowiak 2y ago
  Are we after the great filter?

poikroequ 2y ago

> However, it should be noted that the Drake equation is more of a thought experiment to highlight what we know and what we don't know about the evolution of technological life, rather than an absolute guide to the number of civilizations out there. I fully agree with your second paragraph though.

Beijinger 2y ago

"is a GREAT sign that we’re likely going to have time to expand out of our solar system before some dominant civ just eats us maybe without even noticing us." This is a bold interpretation. Could be a sign of many things. Like that life is much rarer than we assume. Could be that all civilizations run into some kind of energy trap or that civilizations tend to destroy themself with technology “Must be water based, since that’s what we know,” No scientist says that they MUST be water based, but water based would be a decent assumption since we know life can be water based. To look for life in general: look for entropy sources. https://www.sciencealert.com/entropy-could-be-the-secret-to-alien-worlds-being-habitable https://www.sciencealert.com/entropy-could-be-the-secret-to-...

vessenes 2y ago
I think your possible scenarios -- very rare life, energy trap or great winnower / cliff -- actually are all pretty positive in terms of Drake - to me the major point the equations make is just this: if you see any aliens at all, it is likely that you are late to the game of getting extrasolar, and due to the timescales involved, it is most likely that you are very very late to the game. That said, if, say in a billion years, we survive as a race, and still haven't met anyone, then some of those drake choices are very different than we imagine them -- and we must have somehow gotten really lucky, or there is something else very strange going on. Regardless, it would likely be pretty bad news to a single-planet lifeform to meet us at that point, or at least tectonic, depending on how altruistic society as a whole would be at the time of the meeting.

raxxorraxor 2y ago

I would think radio waves to be quite sensible here compared to other-dimensional ghost-aliens roaming the skies. Given radio waves being the primary marker for our own existence and looking at the distance those artificial signals already travelled compared to the size of the cosmos, I believe not having any form of indication for intelligent or any alien life is a surprise.