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gregarioussparrow t1_j6uiaug wrote

I do find it arrogant that we assume all life needs oxygen and water like on earth.

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FireTyme t1_j6uou38 wrote

complex life most likely does. it’s not that arrogant really when u think about it. life needs to be able to create and preserve energy. it’s much harder to create energy when ur environment is incredibly cold. and much harder to preserve energy due to that reason as well.

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1992PlymouthAcclaim t1_j6upw4i wrote

Agreed. PBS SpaceTime posted a really excellent episode the other day outlining the challenges that silicon-based life would face in (most) natural environments. I, like OP, had long assumed that our preference for "life as we know it" was a bit of a blind spot -- I no longer think so. There are so many obstacles standing in the way of the organic evolution of silicon-based life that it wouldn't make sense (in most environments) for nature to favor silicon over carbon.

Given a) the goldilocks scenario that gave rise to life on Earth and b) the apparent dearth of life elsewhere, I think it is reasonable to suspect that it is very difficult for complex life to spring up just about anywhere. Silicon-based life would face an even steeper degree of difficulty. Environments without water (an ideal solvent for the mixture of molecules) might just render the appearance of complex life next to impossible. We can't know that for certain, of course, but I think it's completely reasonable to narrow our search (for the time being) to environments that seem conducive to life rather than expending energy and resources on locales where we have no reason to think that life is even possible.

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TheGreatestOutdoorz t1_j6v37fs wrote

When I went to college, I thought it was so ridiculous that we assumed life had to be carbon based. I majored in biochem and quickly learned why carbon is almost certainly the only base for complex life, and while it kind of made me sad, it was incredibly cool to think about different ways carbon could create complex life forms.

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gulgin t1_j6uq3o3 wrote

Oxygen and water (and to a lesser extent carbon) are very unique in the universe in terms of the convenience of reactions and processes that are easily cyclical. Water has some great properties that help with fundamental chemical processes that aren’t found often elsewhere.

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somethingicanspell t1_j6uyvtc wrote

I’ve never seen a convincing alternative to carbon for chemical based life. Yeah you could use Sulfur, Boron, or silicon but they all are much worse and couldn’t form anywhere near the same amount of stable compounds or in borons case is just much rarer

Water and Oxygen both have alternatives but are probably the most likely compounds used by life because they are ubiquitous, usable at high temperatures, and/or have simpler mechanisms than their alternatives. I’d put complex chemical life at about 99% for carbon, 80% for water, 50% for oxygen.

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Bastdkat t1_j6v096g wrote

Civilization and space-faring require metals which need fire to make which takes oxygen.

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