Pour one out... for water
There’s an old and very silly superstition that says it’s bad luck to toast with water. If you can’t get booze, you’re supposed to use an empty glass rather than water. But what makes this “rule” so ridiculous is how important a role water plays in the life of every creature on our planet. As a famous Hollywood mathematician once said: “life... uh... life finds a way.” And life on Earth is indeed tenacious. From hot rocks deep in the crust, to the fake grout between imitation crazy-paving tiles, to a dirty toilet brush, life will find its niche. And life will make do with all kinds of weird resources to flourish. No sun? Use chemosynthesis. Nothing but concrete? Eat it and excrete sulfuric acid, no problem. A parasite already parasitised the host you wanted? Just parasitise the parasite!
But all life – be it elephant, cat, penguin, oak tree, lichen, bacteria, even viruses and prions that only get counted as life on a technicality – it all requires water.
All life on Earth is cell-based. And water allows cells to absorb nutrients and excrete wastes. It supports a cell’s structure. It’s the ultimate solvent, able to dissolve just about any other chemical given enough time.
And in our planet’s orbit, water exists at the famous “triple point”. Temperatures and pressures are such that it can exist in liquid phase (to support life), in gas phase (to warm the atmosphere) and as a solid (so glaciers and ice-caps grind away rocks and form landscapes and thus habitats for life).
Biologists can imagine – and often observe – all kinds of amazing adaptations that life uses to thrive in the most hostile environments. But always, there has to be a source of liquid water. Even a virus has water inside its tiny creepy lunar-lander alien-looking package of RNA.
Could life exist without water? Ammonia is another electrically-charged molecule that can dissolve organic molecules and many elemental metals. Water is of course one oxygen and two hydrogen atoms. Ammonia is one nitrogen and three hydrogen atoms. The problem with ammonia is that while water will happily accept an extra hydrogen or donate a hydrogen to form various useful compounds, ammonia is more likely to accept a hydrogen... look, it gets all chemistry-set and complicated, but the point is water does more stu , forms more compounds. Water has higher surface tension and stronger bonds too.
Ammonia also won’t freeze until -78 degrees, and it boils at -33 degrees. Of course, that’s under Earth conditions, with our particular density of atmosphere.
Increase air pressure to 60 atmospheres, and ammonia boils at 98 degrees, or about the same as water. Chemical reactions take place more slowly in ammonia though, which means if we did meet intelligent ammonioids, they miiight speeeeak veeeery slooooooowly...
Could conditions exist on a planet somewhere in the Milky Way conducive to ammonia-based life? Since there are likely to be billions of planets in our galaxy alone, the answer is probably... maybe? Given what we know about physics and chemistry right now, there are fundamental reasons why water is the “key ingredient” for life. Exoplanets showing signs of water will always excite us more than hot rocks where it rains glass sideways. And the first confirmed liquid water ocean we spot? Expect that world to get a LOT of attention.
So here’s to water. And I say toast with the stu . It’s an ingredient in almost all our food, after all. Respect it. Celebrate it. How could water possibly bring us bad luck? It’s the only reason any of us are here at all.