September 25, 2009
Water Water Everywhere
Walking in the desert you get an eye for water. It's a sixth sense that leads to some nameless emerald pool hidden among rock crags. I once mapped water holes near the Mexican border with Arizona, on foot for weeks among desolate plains and barren mountains as sharp as broken glass. Looking across this brindle landscape, you'd swear there is not a drop of water, but I found thousands of gallons out there, places where the rain gathered in cracks and bedrock basins. I followed bees and birds to find these spots. Some were marked by archaeological signs, boulders covered in rock art or the ground littered with chipped stone tools where people have been finding water for thousands of years.
When I heard today that water was officially found on the moon, the discovery sounded familiar. Researchers have probed out to a distant and desolate place and found water, much the way I've been nosing through the desert looking for the slightest sign of moisture. On the moon, water is being described as a very fine film covering particles of soil, not liquid like we think of, but molecular. Perhaps one liter could be extracted for every cubic meter of soil. I have dug in desert sand on hot desperate days and found just about that much water before, enough to keep my mouth wet and my body moving to the next site.
Why are we looking for water on the moon? Ostensibly, it is so that someday we might be able to live there, but I believe our search is more intrinsic. The mere presence of water makes the cold and seemingly barren solar system feel more friendly. When I am hunting water in the desert, it is not always because I need to fill my supplies, or because I happened to have been mapping for the government. It is because I want to know where the water is. Just about every jounrey I have undertaken in the wilderness has been about following water. It gives me a deeper sense of the land around me, just like we have a more profound grasp of our larger environment when we learn there is water on the moon.
A second announcement came from NASA today reporting that there is far more water on the surface of Mars than ever expected. Fresh meteorite impacts near the equator have revealed exploded aprons of ice made of what appears to be 99 percent pure water. Prior to this it was believed that outside the Martian poles, water is somewhat rare, but this find suggests that much of the planet just below the surface might be saturated with ice.
It changes the way we look at a planet or a moon when it has water. It changes the way we see space and the rest of our solar system. In fact, water has been found much farther out. Last year a microwave sign of water vapor was detected in a quasar at the edge of the known universe. You notice we don't go to the moon or Mars looking for gold, we go looking for water.
Even looking into the interior of the earth has revealed startling sources beneath us. Recent estimates say that five times the water of our oceans might exist within the earth's mantle, getting there over billions of years as plate tectonics dragged pieces of crust into the hot bowels and melted it, squeezing out its water. At that point, water is not liquid or even steam, but a super-pressurized substance that behaves like plastic filling spaces within the mantle. Computer modeling suggests this material might be a key component of plate tectonics, a flexible structure bending inside the earth. If that is true, without water we might not even have moving plates or mountain ranges. As a catalyst for tectonics, water might ultimately be responsible for every landform we see.
But for how common water is, you've often got to look hard to find it. Walk into the open desert and you must tune your senses. I recall using the 17th century journals of explorer and Jesuit missionary Father Kino who frequently crossed what is now the Mexican border where he mentioned the locations of water holes. One he called Aguaje de la Luna, the Watering Place of the Moon. He had found it one thirsty evening, scrambling through bare rock to find a circle of water in the moonlight. By deciphering Kino's text, I was able to find the same Aguaje de la Luna, a sweet lens of water reflecting the sky inside a naked canyon. I dipped my hands and drank, another explorer among many searching for the one element that makes our world what it is.