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We just don't know enough about life or planet formation to know how this bodes. On its surface, everything that makes the formation of the Earth appear rarer

We just don't know enough about life or planet formation to know how this bodes. On its surface, everything that makes the formation of the Earth appear rarer would suggest life, in general, is rarer but honestly we don't know. We don't even know if there's life on Europa even though there would appear to be all the conditions present to make life as it lives at the bottom of our oceans. We don't even know if water is a reasonable prerequisite for life. We don't know if life has to be carbon-based. Sulfur also presents a reasonable alternative. Would we even recognize other life if was right in front of us if it relied on completely different mechanisms? Maybe even our idea of time is too short lived or long lived to even recognize other complex systems as alive. We shouldn't extrapolate too much from a single data point.

ianai 7y ago
I’m glad I’m not the only one thinking that! All of the paradoxes and stuff just strike me as hubris, at best.
- raducu 7y ago
  But is it just the paradoxes? To me it seems that the early estimations of the numbers of inhabited planets from the Drake equations seem like hubris. Aren't we moving from the "we live in a Star Trek type galaxy, teaming with life" to "well, maybe we are alone in the whole Galaxy but not the Universe" to "Actually, the more we learn about how life on Earth came to be, the more it looks like we are alone in the whole UNIVERSE -- because it seems like every day we find more free terms to the Drake equation". Isn't the whole "we really don't know yet" argument hubris? Isn't it true that you cannot prove the lack of existence of something? Compared to 50 years ago, where do we stand with the question "Are we alone in the universe?" What is 50 years of data telling us, should we be more optimistic or pessimistic? Or is it just saying "we really don't know yet" -- because that's where I believe the real hubris lies -- not accepting the most likely scenario the data we have points to.
raz32dust 7y ago
+1. Also, we don't have many data points to suggest that this is relatively rare that objects from outer solar systems tend to move in later. May be that is quite common, we don't really know - we don't have enough data. And even if we assume it is rare, how rare exactly? The numbers are so uncertain that we can say nothing yet.
raducu 7y ago
Genuinely curious about sulfur-based life, what indications do we have that it could actually form the base for life instead of carbon? I mean I know very little about biochemistry but I do know life on earth has some INCREDIBLY complex biochemistry based on carbon. Also what's the point of sulfur-based life, isn't carbon omnipresent in the universe? Why wouldn't liquid water be an absolute must for life? Wouldn't any kind of complex life need a solvent that would allow the complex biochemistry to take place? What would the alternatives to water then be?
- dumbfoundded 7y ago
  I would just be quoting from wikipedia: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
simonh 7y ago
It simply isn't true that we're completely ignorant on these questions. We know an awful lot about the chemistry of all the known elements and it's pretty clear water and Carbon are by far the best candidates for supporting complex, rich chemistries across a wide range of environmental conditions. It's not that alternative life chemistries are necessarily impossible, but equally it's plausible that they might well be non-viable above a very primitive level at best. They would have many orders of magnitude fewer options available to them for biochemical resources, pathways and molecular geometries to take advantage of. Chemically speaking, not all elements are created equal. Take Sulphur for example. It's far more reactive than carbon, so chemically unstable in many more environmental conditions. It generally only forms linear chains, rather than the complex branching structures of carbon. It also bonds with far fewer other elements in ways that are likely to be chemically useful. If you have carbon available, Sulphur is a very poor substitute. It's high reactivity might make it a passable alternative to Oxygen though.
- dumbfoundded 7y ago
  It sounds like you're paraphrasing the wiki page I attached in a different comment: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi... To address your point, I would say we are extremely ignorant about what the solution space of life looks like. Hydrothermal vents are a very recent discovery. Before this discovery, it was unexpected that such complex and large organisms could exist without light from the sun. As a planet, Earth is teeming with life. Everywhere you look on Earth, you can find it. Even though we have a good understanding of chemistry, we have little clue as to what's important to form complex and self-propagating systems.

ianai 7y ago

I’m glad I’m not the only one thinking that! All of the paradoxes and stuff just strike me as hubris, at best.

raducu 7y ago
But is it just the paradoxes? To me it seems that the early estimations of the numbers of inhabited planets from the Drake equations seem like hubris. Aren't we moving from the "we live in a Star Trek type galaxy, teaming with life" to "well, maybe we are alone in the whole Galaxy but not the Universe" to "Actually, the more we learn about how life on Earth came to be, the more it looks like we are alone in the whole UNIVERSE -- because it seems like every day we find more free terms to the Drake equation". Isn't the whole "we really don't know yet" argument hubris? Isn't it true that you cannot prove the lack of existence of something? Compared to 50 years ago, where do we stand with the question "Are we alone in the universe?" What is 50 years of data telling us, should we be more optimistic or pessimistic? Or is it just saying "we really don't know yet" -- because that's where I believe the real hubris lies -- not accepting the most likely scenario the data we have points to.

raz32dust 7y ago

+1. Also, we don't have many data points to suggest that this is relatively rare that objects from outer solar systems tend to move in later. May be that is quite common, we don't really know - we don't have enough data. And even if we assume it is rare, how rare exactly? The numbers are so uncertain that we can say nothing yet.

raducu 7y ago

Genuinely curious about sulfur-based life, what indications do we have that it could actually form the base for life instead of carbon? I mean I know very little about biochemistry but I do know life on earth has some INCREDIBLY complex biochemistry based on carbon. Also what's the point of sulfur-based life, isn't carbon omnipresent in the universe? Why wouldn't liquid water be an absolute must for life? Wouldn't any kind of complex life need a solvent that would allow the complex biochemistry to take place? What would the alternatives to water then be?

dumbfoundded 7y ago
I would just be quoting from wikipedia: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...

simonh 7y ago

It simply isn't true that we're completely ignorant on these questions. We know an awful lot about the chemistry of all the known elements and it's pretty clear water and Carbon are by far the best candidates for supporting complex, rich chemistries across a wide range of environmental conditions. It's not that alternative life chemistries are necessarily impossible, but equally it's plausible that they might well be non-viable above a very primitive level at best. They would have many orders of magnitude fewer options available to them for biochemical resources, pathways and molecular geometries to take advantage of. Chemically speaking, not all elements are created equal. Take Sulphur for example. It's far more reactive than carbon, so chemically unstable in many more environmental conditions. It generally only forms linear chains, rather than the complex branching structures of carbon. It also bonds with far fewer other elements in ways that are likely to be chemically useful. If you have carbon available, Sulphur is a very poor substitute. It's high reactivity might make it a passable alternative to Oxygen though.

dumbfoundded 7y ago
It sounds like you're paraphrasing the wiki page I attached in a different comment: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi... To address your point, I would say we are extremely ignorant about what the solution space of life looks like. Hydrothermal vents are a very recent discovery. Before this discovery, it was unexpected that such complex and large organisms could exist without light from the sun. As a planet, Earth is teeming with life. Everywhere you look on Earth, you can find it. Even though we have a good understanding of chemistry, we have little clue as to what's important to form complex and self-propagating systems.