James Webb spies distant exoplanet that could be wet, wild, and Hycean The James Webb Space Telescope continues to deliver the goods with scientists publishing insights into the atmospheric properties of a habitable-zone exoplanet. The planet in question is the snappily named K2-18 b, which orbits the dwarf star K2-18. It lies 120 light-years away in the constellation Leo and is approximately 8.6 …
The ocean – if present – could, for example, simply be too hot to be habitable.
Presumably there's a high atmospheric pressure so the boiling point at the surface is going to be considerably higher than 100°C but I don't see why that should preclude life. There are plenty of Earth critters living and thriving around hydrothermal vents where the temperatures well exceed 100°C.
You are all aware of the Weak Anthropic Principle - "The world is the way it is because if it wasn't we wouldn't be here to observe it". That does not mean there cannot be a Weak K2-18 biesian Principle too. Living in their endless hot sea, the idea that life could exist on a (relatively) cold planet with large landmasses would seem absurd.
The current records on Earth are 130°C for survival and 122°C for reproduction. A hyperthermophile principle would require something able to think one up, which is well beyond the abilities of Earth bacteria. Complex multicellular life on Earth requires moderate temperatures, which can be found close to but not in a hydrothermal vent.
Complex multicellular life is a whole different thing, and there is strong evidence that evolved only once whereas most of evolution is rife with repeats of the same paths. If anyone is looking for the blocker to the Drake equation, I'm thinking that transition to multicellular life which from the descriptions of what they think the steps were sounds like a bullet hitting a bullet shot by someone sitting on a train traveling at .5 c.
Don't forget "ocean" doesn't necessarily mean water. Could be liquefied gas (big gravity, huge pressure) or some hydrocarbon.
Life on such a planet would be definitely not similar to what we're used to, if only due to the crushing gravity and other fundamental differences with Earth (high pressure, high temperature, strange chemical compositions, probably strong solar radiation (or not), and so on). Nature would certainly find all kind of original solutions we haven't thought of.
...permutations of the Drake Equation it is, in my opinion, fruitless to think that we will find life as we know it elsewhere in the universe. There are too many possible forms of life for we humans to be hung up on finding more humans. Evidence of extraterrestrial life will most likely never be found if we keep looking at our universe and expecting to see ourselves in a mirror.
We look for what we know to look for - carbon based life with an oxygen metabolism.
Looking for signals or constructed structures does not depend on that but we've not had any luck in that venture and we would need to be very lucky indeed as we would need to be directly in the path of a narrow beam to stand any chance of getting a definite signal from more than a few dozen light years. As for detecting alien structures, we're a generation or two of space telescopes away from that being feasible.
We are now to the point where we can look at the composition of alien atmospheres so looking for metabolites is an obvious step but what metabolites should we look for? That's easy if we are looking for carbon based life as it's the only type we know works so that's what we look for. Non-carbon based life (if that's even possible at non-extreme temperatures and pressures) would not produce metabolite we could predict so we don't have a clue as to what to look for so why bother? The same is true for hypothetical carbon based non-oxygen using life, we don't know what to look for.
We'll look for "it's life Jim but not as we know it" when we have a sensible idea of what to look for, until then we look for what we know works
It's far better to try and fail than not to try at all.
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