What dictates that extra terrestrial life requires water in the same way as we do? Even on earth we have fish who can’t live in the open air, and people who can’t live underwater.
What is to say that ET can’t eat space rocks to obtain all of its nutrients, or even more, what is to say that they require nutrients at all?
Edit: Thanks for all the wonderful answers. Makes perfect sense. They aren’t so much saying we HAVE to have water to create life, more that we only know how that works and looking for the unknown in the vast expanse that is the universe would be the worlds largest needle in a haystack game.
In: Planetary Science
Water is good at chemistry. If you want to mix a bunch of random molecules together, then you need some sort of liquid to dissolve them in. Otherwise they aren’t really going to mix. Think baking a cake with just dry ingredients. If we accept life as a result of random chemistry then you look for the thing that’s best at facilitating that, and water is uniquely good at that while being simple enough to be relatively abundant.
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