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mankind has been extremely lucky with our environments, among others: - Jupiter & Saturn pick out most of the comets, so we encounter massive reset only very r

mankind has been extremely lucky with our environments, among others: - Jupiter & Saturn pick out most of the comets, so we encounter massive reset only very rarely - thanx to hitting other planet long time ago, we have a spinning molten metal core inside planet generating magnetic shield for all nasty radiation - moon gives us tides & stability - our sun is just the right size and age to be stable - we're located at quiet part of the galaxy, which itself is pretty stable I think some primitive life (ie stromatolytes equivalent) can exist on many places, simply because it happened on our planet very early when it was very violent place to be - so random arrangement of matter into self-reproduction is feasible. But to evolve into specialized multi-cellular organisms took more than billion of years, a step that might not happen at all. And to create an intelligent life is another massive step up (or accident). There is Drake equation to manifest it, but basically all variables in it can be anything including 0, so it's kind of useless. So from my perspective there are couple of options: - universe is too young (if you consider average star age compared to estimated universe age), so we're one of the first sentient arrivals, others are behind in evolution - we're just not interesting enough to be contacted by superior races - just look at the news, I wouldn't blame them. We're 'meh' category at best, although most like to think of themselves in very different perspective - we're fucking alone, weird random anomaly (by far the most scary option of them all) There is a wonderful TV series from BBC called Earth: Power of the Planet, which explores this topic to great details, highly recommended!

raverbashing 9y ago
Earth was lucky but Mars and Venus (now) have been unlucky. Mars lost its magnetic field long ago, but it had one once. Venus, well, it's an acid rain oven but it could have been different. Both could have had conditions for life (as we know it) once.
dom96 9y ago
You're assuming that all life will be like ours. This is a safe bet, but there could be very many ways for life to exist.
- tome 9y ago
  Can you suggest another one?
  - Razengan 9y ago
    • Robots that perform all the functions humans do, including making copies of themselves and teaching each other. • Hive-mind species where there are no individuals. • Species without any gender or sexual reproduction, whose individuals are spontaneously "born" in specific locations and conditions on their planet. • "Species" consisting of a single, massive/long-lived individual. • Parasitic intelligences that "infect" various other, unrelated species and direct them towards the goals of the parasites. • Lifeforms floating around in gas giants or even in nebulas. • Life-bearing planets themselves being a lifeform; that "reproduces" when the civilizations it supported upon itself go on to terraform other planets to become like their home planet.
    - tome 9y ago
      When dom96 said "there could be very many ways for life to exist" I understood that to mean there could be very many different "biological substrates" (for want of a better term), nothing to do with how the species organises itself socially. The challenge is to come up with a hypothesis for "life" that's not based on long carbon chains.
      - saiya-jin 9y ago
        I agree that only our imagination is the limit when discussing potential life. If matter that is not completely frozen (ie atoms stop moving) will eventually organize into some self-replication, any energy source could be enough. It could be on the surface on active star, neutron star (someone already tackled that in sci-fi), all kinds of dwarfs, nebulas, maybe even something living off dark energy? Or black hole. Energy means movement, and if matter/energy will eventually arrange into something 'alive', it might be enough.
    - TeMPOraL 9y ago
zimpenfish 9y ago
> we're one of the first sentient arrivals Given we didn't arrive until 14.5bn years into the universe's existence, I'd find that extremely hard to fathom.
- saiya-jin 9y ago
  Our solar system is +-4bn years old, so there have been only cca 3 previous generations of similar stars (and it's kind of nice to have heavier elements from the first generations of stars in abundance - I would expect forming life just from He and H wouldn't work well). Let's ignore the 'bn' part - this place is 14-old. Our system is 4-old. Life is 3-old. Multi-cellular is 2-old. Sentient is 0.00001 old. With usual star life has +- 10 to escape, or it will be destroyed. It doesn't sound so far-fetched to me. But maybe it's all different - plenty of life all around the place, even super smart & evolved, but maybe speed of light simply can't be broken no matter what. That would dampen any rise of galactic civilization. Or some other unbreakable constraint.
  - zimpenfish 9y ago
    > there have been only cca 3 previous generations of similar stars That assumes they're consecutive, not overlapping. Assume it takes 4-old, space them out by 0.1-old, and you could have 100+ generations between the first and us.
joshuahedlund 9y ago
A good book that explores some of these factors for our environment is Rare Earth by Peter D. Ward and Donald Brownlee. While it's true that life "out there" may look vastly different, I feel like sometimes ET-optimists use that as a hand-wavy defense that overlooks two curious details: First, we haven't found any different-looking-life-out-there on, say, Venus, or Mars... so clearly even in a solar system with some "lucky" aspects for life there are plenty of environments where life just doesn't "find a way." Second, the relative quickness with which our kind of life appeared in Earth's history suggests an oddity that we haven't even found other examples of our-general-kind-of-life out there. A good book that explores some of the proposed solutions to the Fermi Paradox is Where is Everybody? by Stephen Webb. (It does a good job using math to explain why it's a little surprising that we haven't found ET life even within our own galaxy, and it does a good job knocking down most of the sociological explanations by noting that it would require every other civilization in the galaxy to behave that way with no exceptions.)

raverbashing 9y ago

Earth was lucky but Mars and Venus (now) have been unlucky. Mars lost its magnetic field long ago, but it had one once. Venus, well, it's an acid rain oven but it could have been different. Both could have had conditions for life (as we know it) once.

dom96 9y ago

You're assuming that all life will be like ours. This is a safe bet, but there could be very many ways for life to exist.

tome 9y ago
Can you suggest another one?
- Razengan 9y ago
  • Robots that perform all the functions humans do, including making copies of themselves and teaching each other. • Hive-mind species where there are no individuals. • Species without any gender or sexual reproduction, whose individuals are spontaneously "born" in specific locations and conditions on their planet. • "Species" consisting of a single, massive/long-lived individual. • Parasitic intelligences that "infect" various other, unrelated species and direct them towards the goals of the parasites. • Lifeforms floating around in gas giants or even in nebulas. • Life-bearing planets themselves being a lifeform; that "reproduces" when the civilizations it supported upon itself go on to terraform other planets to become like their home planet.
  - tome 9y ago
    When dom96 said "there could be very many ways for life to exist" I understood that to mean there could be very many different "biological substrates" (for want of a better term), nothing to do with how the species organises itself socially. The challenge is to come up with a hypothesis for "life" that's not based on long carbon chains.
    - saiya-jin 9y ago
      I agree that only our imagination is the limit when discussing potential life. If matter that is not completely frozen (ie atoms stop moving) will eventually organize into some self-replication, any energy source could be enough. It could be on the surface on active star, neutron star (someone already tackled that in sci-fi), all kinds of dwarfs, nebulas, maybe even something living off dark energy? Or black hole. Energy means movement, and if matter/energy will eventually arrange into something 'alive', it might be enough.
  - TeMPOraL 9y ago

zimpenfish 9y ago

> we're one of the first sentient arrivals Given we didn't arrive until 14.5bn years into the universe's existence, I'd find that extremely hard to fathom.

saiya-jin 9y ago
Our solar system is +-4bn years old, so there have been only cca 3 previous generations of similar stars (and it's kind of nice to have heavier elements from the first generations of stars in abundance - I would expect forming life just from He and H wouldn't work well). Let's ignore the 'bn' part - this place is 14-old. Our system is 4-old. Life is 3-old. Multi-cellular is 2-old. Sentient is 0.00001 old. With usual star life has +- 10 to escape, or it will be destroyed. It doesn't sound so far-fetched to me. But maybe it's all different - plenty of life all around the place, even super smart & evolved, but maybe speed of light simply can't be broken no matter what. That would dampen any rise of galactic civilization. Or some other unbreakable constraint.
- zimpenfish 9y ago
  > there have been only cca 3 previous generations of similar stars That assumes they're consecutive, not overlapping. Assume it takes 4-old, space them out by 0.1-old, and you could have 100+ generations between the first and us.

joshuahedlund 9y ago

A good book that explores some of these factors for our environment is Rare Earth by Peter D. Ward and Donald Brownlee. While it's true that life "out there" may look vastly different, I feel like sometimes ET-optimists use that as a hand-wavy defense that overlooks two curious details: First, we haven't found any different-looking-life-out-there on, say, Venus, or Mars... so clearly even in a solar system with some "lucky" aspects for life there are plenty of environments where life just doesn't "find a way." Second, the relative quickness with which our kind of life appeared in Earth's history suggests an oddity that we haven't even found other examples of our-general-kind-of-life out there. A good book that explores some of the proposed solutions to the Fermi Paradox is Where is Everybody? by Stephen Webb. (It does a good job using math to explain why it's a little surprising that we haven't found ET life even within our own galaxy, and it does a good job knocking down most of the sociological explanations by noting that it would require every other civilization in the galaxy to behave that way with no exceptions.)