It’s very close-minded of scientists to think that all life in the (as far as we know) infinite universe is as water dependent as life on earth. Yet this is exactly what the scientists who get excited with evidence of water having been on mars are saying. Yes, all life on earth needs water to sustain itself, and it’s probably true that the presence of water on another planet means life exists there too, but this does not imply that the absence of water destroys any possibility of life.

I remember a high school biology book with something like 7 criteria that must be met before a thing can be considered alive. Criteria like: intake of nutrients, output of waste, ability to reproduce, etc. I can’t be bothered to check and see if one of the criteria was water related, but if one was, it should be removed. Surely, there are, right now, things roaming the surfaces of other orbiting bodies which, by virtue of their size, appearance, and ability to move, we would doubtless consider alive, but which do not have any need of water. To use the requirements of life on earth as a determinant of whether environments on other planets can sustain life is plain stupid.