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One thing that bothers me is that papers like this always assume alien life will look exactly like life on Earth. It must be the same distance from the sun as u

One thing that bothers me is that papers like this always assume alien life will look exactly like life on Earth. It must be the same distance from the sun as us, have water and proteins like us, etc. If we effectively limit the definition of "life" to "the types of organisms we see on Earth", then of course we will never find life anywhere else. Maybe there are aliens that live on a gas giant and they "eat" the lighting rather than food, and their bodies look more like circuitry than the chemical life on Earth. Maybe there is a planet with a very strong magnetic field, and the life there is kind of like an electromagnet. They have bodies high in copper and the current of the ocean moves them through the magnetic field and generates electrical energy. It makes sense that we restrict our search for life forms we know to be possible while we are stuck with limited tools at our disposal. But I don't want us to overlook some amazing discoveries because we have put blinders on.

learnstats2 6y ago
It's reasonable to understand that 'life' here means 'we can meaningfully communicate across space with', since that is the intended purpose here. It seems almost infinitely more likely that we will be able to communicate with life that is like us. Even if that turns out not to be essential, it is a better starting place to spend your limited resources looking.
- teknopaul 6y ago
  I think this very article disproves your hypothesis. Life like us is probably so far away and so short-lived that we will never be able to communicate. An intelligence that is near enough to reply & able to survive millions of years (so its lifespan crosses ours) might provide some results. If we start sending out signals and ask how long will it take for a reply? 17,000 years from something like us. Thats no use. Might be better to phone every star in the neighbourhood starting with the nearest, and see if anyone picks up.
  - Balgair 6y ago
    Our understanding of the universe and physics is still young. We're reasonably sure about 'normal' matter, things like you, a beer, or a star. Unfortunately, that's only about 5% of the universe that we know of today. Things like Dark Matter, well, we know it falls down. That's about it, really. There's a lot of theories about it though. More unfortunately, we think Dark Matter is about 20% of the universe. Then there's Dark Energy. It makes things fall up (?!). And we're not super sure about that, either. Most unfortunately, Dark Energy is about 75% of the universe. We don't have a clue if any intelligence is even using photons to communicate anymore. Most of the universe doesn't seem to really interact with them anyways. And that's with this limited understanding of 'Dark' things. We're still standing at the shore of a vast ocean.
fennecfoxen 6y ago
The start of life is basically a statistics game waiting for a system to spontaneously enter the right self-reproducing state, and it is relatively easy for a system combining water and various mostly-carbon-based molecules to enter into that state. We thus suppose that life looks like life on Earth because life on Earth has several properties which allowed it to come into existence. By contrast, there are no known states that cause a strong planetary electromagnetic field to rearrange copper into self-reproducing patterns: if anything, such electromagnetic fields are more likely to disrupt any spontaneous order that happens to arise. So it's true there may be other systems of life out there, but too much handwaving about that fact can obscure the fact that the other candidates for ordered systems arising from chaos are weak candidates. It would be unwise to rely on this wild speculation while trying to responsibly and conservatively estimate how much life there is.
- teknopaul 6y ago
  Right now there is a lot of active search for life based on the habitable zone theory. I also think that we should open up our ideas. We might find something of intellect and of interest closer than 17000 light years. If nearest carbon based life if so far there is not much to be learned. If we can find even a mildly interesting self supporting system in our own solar system we may not be able to play golf but we might be able to communicate and learn. I also think we are foolish to not look for intelligence on earth. We killed off the neanderthals. There is more hope of bringing them back and asking for an opinion than finding little green men.
  - fennecfoxen 6y ago
    We might indeed find something of intellect closer! It would indeed be interesting! It is not, however, something we have reason to expect would be particularly probable. I am unsure what variety of "opinion" you hope to extract from your hypothetical Neanderthal, and take the opportunity to note that, as social mammals with large and adaptable brains, the opinion systems of intelligent hominids are substantially shaped by their upbringing and how they relate to the society around them, particularly as regards the more complex systems of thought.
- 6y ago

learnstats2 6y ago

It's reasonable to understand that 'life' here means 'we can meaningfully communicate across space with', since that is the intended purpose here. It seems almost infinitely more likely that we will be able to communicate with life that is like us. Even if that turns out not to be essential, it is a better starting place to spend your limited resources looking.

teknopaul 6y ago
I think this very article disproves your hypothesis. Life like us is probably so far away and so short-lived that we will never be able to communicate. An intelligence that is near enough to reply & able to survive millions of years (so its lifespan crosses ours) might provide some results. If we start sending out signals and ask how long will it take for a reply? 17,000 years from something like us. Thats no use. Might be better to phone every star in the neighbourhood starting with the nearest, and see if anyone picks up.
- Balgair 6y ago
  Our understanding of the universe and physics is still young. We're reasonably sure about 'normal' matter, things like you, a beer, or a star. Unfortunately, that's only about 5% of the universe that we know of today. Things like Dark Matter, well, we know it falls down. That's about it, really. There's a lot of theories about it though. More unfortunately, we think Dark Matter is about 20% of the universe. Then there's Dark Energy. It makes things fall up (?!). And we're not super sure about that, either. Most unfortunately, Dark Energy is about 75% of the universe. We don't have a clue if any intelligence is even using photons to communicate anymore. Most of the universe doesn't seem to really interact with them anyways. And that's with this limited understanding of 'Dark' things. We're still standing at the shore of a vast ocean.

fennecfoxen 6y ago

The start of life is basically a statistics game waiting for a system to spontaneously enter the right self-reproducing state, and it is relatively easy for a system combining water and various mostly-carbon-based molecules to enter into that state. We thus suppose that life looks like life on Earth because life on Earth has several properties which allowed it to come into existence. By contrast, there are no known states that cause a strong planetary electromagnetic field to rearrange copper into self-reproducing patterns: if anything, such electromagnetic fields are more likely to disrupt any spontaneous order that happens to arise. So it's true there may be other systems of life out there, but too much handwaving about that fact can obscure the fact that the other candidates for ordered systems arising from chaos are weak candidates. It would be unwise to rely on this wild speculation while trying to responsibly and conservatively estimate how much life there is.

teknopaul 6y ago
Right now there is a lot of active search for life based on the habitable zone theory. I also think that we should open up our ideas. We might find something of intellect and of interest closer than 17000 light years. If nearest carbon based life if so far there is not much to be learned. If we can find even a mildly interesting self supporting system in our own solar system we may not be able to play golf but we might be able to communicate and learn. I also think we are foolish to not look for intelligence on earth. We killed off the neanderthals. There is more hope of bringing them back and asking for an opinion than finding little green men.
- fennecfoxen 6y ago
  We might indeed find something of intellect closer! It would indeed be interesting! It is not, however, something we have reason to expect would be particularly probable. I am unsure what variety of "opinion" you hope to extract from your hypothetical Neanderthal, and take the opportunity to note that, as social mammals with large and adaptable brains, the opinion systems of intelligent hominids are substantially shaped by their upbringing and how they relate to the society around them, particularly as regards the more complex systems of thought.
6y ago