Dear Matt: When we went to the desert once, there was a ranger who told us that there were lots of things that could live there, even though it mostly looked like rocks and sand. Do all deserts have things living in them? Is there any place where nothing lives, like the ­Arctic? — Nameless, via email

Photo by Rick Geary

Just because you wouldn’t like to live in ice or burning sand doesn’t mean there aren’t things that would be very happy there. As long as we can call organisms like microbes “life,” there’s plenty of stuff partying on virtually every square inch of Earth. So you guess nothing could survive in the Arctic, on the rim of an active volcano, in nuclear waste or boiling geysers? Wrong, wrong. There’s a long list of varied organisms, called extremophiles, that we’ve found in just such locations. So, maybe there isn’t any place on Earth devoid of life, huh? Wrong, ­wrong.

Pack your bags, we’re off to South America. To a big desert, the Atacama, which runs about 600 miles north-south in Chile. One end of the desert actually has some permanent pools of water where a native flock of flamingos survives on red algae. But head south, and you’ve pretty much got a moonscape. Or, rather, a Mars-scape, since it’s an area favored by NASA geologists preparing for the colonization of Mars. They believe it’s the best place to study the minimum requirements for life in a very Mars-like ­rockscape.

Until recently, science guys declared the Atacama the only place on the planet, so far discovered, to support absolutely no life. And why? No water. None. Nothing. Somehow the science guys have figured out that most of the Atacama Desert has had no rain in 300 years. Soil testing has revealed no microbes, bacteria — nothing alive at all. The Atacama actually is located between a lush rainforest on the east and the Pacific Ocean on the west, but it’s blocked from both by mountain ­ranges.

But as one scientist found out in 2006, that doesn’t mean water doesn’t appear in the area under proper conditions. Out on a walk one day through the desert’s lifeless rubble, a geologist from a Spanish university noticed a strange layer of something in a rock made up mostly of what we would call table salt. He broke off a piece, took it back to the lab, dissolved it in water, put the water on a slide, and found living microbes in the salt rock. He went back and took more samples and found more microbes. So, the dead Atacama — at least in some locations — does support ­life.

Where does the water come from? Well, let’s say humidity. Average humidity in the desert in the daytime is from 1 to 2 percent. But at night the air gets cold, and cold air doesn’t hold as much water as hot air. When the air is cold and humidity rises to about 75 percent, the salt rock captures the moisture, and the organisms in the rock suck up what filters down to ­them.

Apparently we’ll have to keep looking for another dead zone. The Atacama is a bit more lively than we ­thought.

Question for Matthew Alice: Muslims face toward the Kaaba in Mecca during their prayers. Do they face using a simple compass heading, or do they face the shortest distance using a Great Circle heading? If they face using the shortest distance, shouldn’t they face a direct path through the ­earth?

The Kaaba, a shrine in the center of the Great Mosque in Mecca, is the target of Muslim prayer five times a day. But how one finds the Kaaba seems to depend on your own background. Some use a simple compass, which actually gives a false heading, according to sticklers for accuracy. Qibla is the Arabic name for the direction between you and Mecca. The most contemporary way to find qibla is to look it up on your computer (e.g., qiblalocator.com — enter your address; it gives you the compass heading). There are booklets listing large cities and their corresponding headings. Mosques have wall marks, many homes have the direction marked on the ceiling. Or if you’re adventurous, you can use the sun to calculate your direction. Qibla these days is determined using a true north (Great Circle) heading, since Earth is a sphere (more or less), and any direction determined on a flat map will be distorted. Using true north, the direction of prayer from San Diego is toward Poway, that is, northeast. In fact, in whatever city, all directions from North America are toward the northeast, only varying in degree from true north. The idea of using true north is that it gives you the shortest and most correct distance to the Kaaba and Mecca. The shortest distance is the most effective way to pray to have your voice heard. Praying into the dirt to send your prayer through the earth isn’t such a cool ­idea.