Water on Mars: What Does It Mean?

On June 22, NASA astronomers held a press conference to announce their discovery of “recently” cut gullies, indicators of flowing water, on the Martian surface.1, 2 The discovery stirred excitement for several reasons—some practical, some ideological, and some (perhaps) political.

First, some background: More than a year ago, the Mars Global Surveyor, which began orbiting Mars in 1997, confirmed the validity of old Mariner 9 photos (from 1972). Those photos showed flood channels cut previous to 3.5 billion years ago, that is, before Mars lost most of its primordial atmosphere to outer space. Since that time, Mars has been too cold and too dry to hold liquid water on its surface for more than a second or two.

These newly observed channels, however, seem to have formed more recently than a few million years ago.3 Asteroids and meteorites have not yet pocked them with craters, nor have the famous Martian dust storms filled them in or worn them down. What’s going on?

The scenario proposed by the discovery team is this: A small amount of the water that either existed on Mars four billion years ago or that arrived more recently (from infalling comets) managed to seep underground into an aquifer. A recent crustal episode, such as a volcanic or other geothermal event, forced the underground water to the surface. The first water to hit the surface instantly froze, forming a dam to hold back the rest of the water. Eventually, the built-up pressure behind the dam caused it to break, unleashing a torrent. A torrent unleashed high up on a steep slope, where these channels were observed, could make their mark in a few seconds before evaporating or freezing.

In practical terms, the discovery suggests that undisturbed aquifers may still exist on Mars. Such aquifers, though hard to reach, might help sustain future astronauts exploring the Martian surface. On the other hand, water contained in the planet’s frozen polar caps (predominantly frozen carbon dioxide with a tiny amount of frozen water) would likely be easier to locate and cheaper to mine.

The ideological reason for the excitement is the popular (though illogical) notion that “liquid water means life.” While no one disputes the necessity of water for life, science has shown that liquid water is merely one of many requirements for life, not the only requirement. Researchers have identified more than a hundred different requirements, independent of water, for life to exist on any given planet in any given planetary system.4 Most of these requirements reflect substantially greater fine-tuning than does liquid water.

Even if all the other requirements were met on a planet, the presence of liquid water is not enough to support life. Living creatures need an abundance of water in all three states (gas, liquid, and solid) available for a long time. Land life additionally demands an abundant and stable water cycle. That Mars never had one, the Mars Global Surveyor affirms. As Genesis 1:6-8 declares—and scientific evidence demonstrates—the existence of an abundant, stable water cycle constitutes a miracle.5 (Incidentally, comets, which are mostly frozen water, carry at least some water to virtually all solar system bodies. Even the moon has some of this comet-delivered water.6)

Will NASA ever find evidence of life on Mars? I expect so, if NASA searches with sufficient diligence.7 Just as meteors travel from Mars to Earth so also do they travel from Earth to Mars. Over the past four billion years at least several billion tons of Earth material, much of it life-carrying material, has landed on Mars. Spread over the Martian surface, this deposition adds up to a very low density of life material, and given the harshness of the Martian environment, almost all this material will have been broken down into molecules untraceable to life. Nevertheless, NASA has a shot at discovering life’s remains on Mars. Such a discovery would testify to certain species’ marvelous, God-given capacity to survive the frigid, near zero vacuum, radiation-riddled trip.

A possible political reason for the stir over the water channel discovery is that NASA’s Mars missions are up for funding consideration. A well-timed “spectacular” Mars discovery might influence legislators’ generosity, some cynics suggest. Personally, I am in favor of unmanned Mars exploration. The track record of the past three decades has been good for Christian apologetics. The more we learn about Mars the more evidence we uncover for the divine design of Earth.