Complex Numbers

All Wet

There was a Shyamalan movie a while back, Signs, that was all about (spoiler here) aliens whose only weakness was water. Everybody (except, apparently, Syamalan) wondered why aliens would even bother visiting a planet whose surface is mostly covered in the stuff, and where it regularly falls out of the sky. Decent movie, stupid premise. And don't get me started on what the Wicked Witch of the West must have smelled like if all it took to melt her was water.

Anyway, the point is, water's kind of important for us.

http://nautil.us/blog/-why-water-is-weird

Why Water Is Weird

Water can appear to be “fine-tuned” for life.

Well, duh. Anthropic principle: if it weren't, we wouldn't be here to gawk at it.

In their 2018 study, Hajime Tanaka, John Russo, and Kenji Akahane—all researchers in the Department of Fundamental Engineering at the University of Tokyo, in Japan—tried to tease apart what makes water unique among liquids.

Whatever the technical reason for it, it is unique as far as we know. One weirdness that they touch on in this article: ice is less dense than water, so it floats. What the author doesn't mention is how this protects life in the water; as the ice forms a barrier, the liquid water underneath becomes more temperature-stable, keeping aquatic organisms from freezing (usually). This probably helped evolution along.

The ancient Greeks thought water was one of the four “essential” elements, the others being earth, air, and fire. Homeopathy, which purports to cure illness using small doses of disease-causing substances dissolved in water, evolved out of this, Saykally said. But there are more modern magical claims about so-called “structured” or “hexagonal” water. Some “wellness” practitioners claim humans age in part because we don’t replenish our stock of structured water. Depending on water’s structure, they say, it can penetrate your cell walls more effectively and has all kinds of health benefits.

Well, water does have all kinds of health benefits. As the article points out, though, "structured water" is concentrated bullshit.

The ancient Greeks may have been wrong about water being an essential element, but Saykally says it’s no coincidence that water is essential for life on Earth.

I wouldn't say "wrong," exactly. Just that this was the state of knowledge at the time. Aristotle was wrong a lot, too, but we still study his stuff because it helped form the foundation for modern thought.

Anyway, some people speculate that other liquids might help form life on other worlds. Methane, for example. But anyone positing such a thing is going to have to explain how methane, which has rotational symmetry, can do all the fun things that water, which does not, does. I'm not saying it's impossible, of course; it's a big universe. But I don't think it's very likely.

Maybe there are sentient aliens that are based on ethanol instead of water. I wonder if they get pulled over if they have too much water in their bloodstream...