We have come all this way because geologists studying Mars have designated Iceland a Mars analogue. In 1976, when the Viking Lander returned color images of the Red Planet, scientists realized that Mars bears a striking resemblance to the landscape sliding below Oscar’s little airplane. Iceland is, in many places, an arctic desert devoid of vegetation and untouched by humanity. These days, NASA-supported scientists regularly visit to study this volcano-ridden island to compare it to its distant relative, Mars. The theory is that by studying Iceland, scientists can better understand the workings of the Red Planet. Iceland is only twenty million years old, a geological babe, and thus relatively unweathered, a primeval landscape. The absence of trees on the Icelandic landscape is a blessing, revealing the island’s geological makeup. Mars is similarly bare. Iceland festers with active and dormant volcanoes – just as Mars does. The resemblance makes it possible to work out significant aspects of the geologic history of both places by comparing the two.
Mars is so reminiscent of Earth that it is considered “semi-habitable.” The atmosphere is only one percent as dense as ours, but breathable air could be extracted from it. The Martian day, or “sol,” lasts about as long as a day on Earth; a Martian year consists of 687 Earth days. Like Earth, Mars has its seasons, but they last twice as long. And Martian weather conditions are anything but monotonous or predictable. In 1997, when Pathfinder landed on Mars, its tiny weather station gathered data on the local Martian weather, which NASA posted on the Internet. The reports showed that temperatures range from 60° F at noon to –100° F at night. Travelers’ advisory: because of the much lower atmospheric pressure on Mars, surface temperatures differ drastically from air temperatures. If you were standing on the surface in midday, your feet would be warm and snug, but the fluids in your head would freeze. Mars’ atmosphere has fog, wind, and red dust, lending pink tints to a sky accented by two small, misshapen moons, Phobos (“fear”) and Deimos (“terror”).
Mars resembles Earth in other ways. Its polar ice caps wax and wane seasonally. There are clouds. There is ample geologic evidence that rivers once flowed freely on its surface. The stage has long been set for life to appear there. Yet the Earth teems with life, while Mars appears barren, at least on the surface. Why? No one really knows, yet the answers may lurk in the perplexing differences between the two planets.
The Earth’s surface consists of overlapping, often ill-fitting plates covering its molten interior. They form a crust like an eggshell, thin and brittle. They bump and grind against each other; occasionally they pull apart, as they are doing now in Iceland, giving rise to earthquakes and volcanoes and mountain ridges lurking beneath the oceans. Iceland sits right on the spine of the Mid-Atlantic Ridge, a segment of the Mid-Ocean Ridge, which is the longest mountain range on Earth, extending 40,000 miles, or one-and-a-half times around the planet. Iceland’s unique placement means that half of it belongs, in a geological sense, to the European continent, and half to the American. And the two halves are pulling apart at the rate of one centimeter a year. That doesn’t sound like a lot, but when this movement occurs over the course of ten or twelve million years, it eventually becomes a very big deal. Iceland could break apart and be absorbed by other, larger land masses. Or if it surges in volcanic activity, it could enlarge itself, adding enough real estate to accommodate many more hardy souls. For now, a seam runs right through Iceland, clearly marked in some places by a narrow chasm and in others by small streams and little cracks. If you jump across one of the cracks, you jump from one continent to another.
At this moment, no one knows for certain if Mars has or had plates similar to Earth’s, or, if the Red Planet did have them, how they operated. If Mars never had crustal plates, their absence poses interesting questions about how it developed without them. And if it did, we see no direct evidence of them – not yet, at any rate. The geologic processes associated with crustal plates would have affected the way life did, or did not, develop on Mars.
“Nothing you see here is more than ten thousand years old,” Jim shouts over the whine of the engine, as we pass over the Reykjanes Peninsula region of southwest Iceland, “and some of it is only five thousand years old, or less.” Jim lives by the geological clock, which extends billions of years, all the way back to the formation of the universe. The universe is an old, old place, perhaps 15 billion years old, possibly more, and the planets of our Solar System are old, too, something on the order of 4.7 billion years. When you measure time in billions of years, you dismiss a million years as a hiccup. A span of five or ten thousand years is insignificant. The concept of a year, the time it takes for the Earth to complete a revolution around the Sun, scarcely seems an adequate yardstick for measuring the development of the universe and the planets. Iceland’s arriviste status in the geological scheme of things is rare and intriguing; the place teems with clues about the formation of Earth, of Mars, and of the entire Solar System. To understand the Red Planet, even partially, is to understand something about the nature of the universe, to catch glimpses of our distant past and our future, to extend perception to a scale much larger than ordinary human comprehension, to harness the imagination to the intellect, and the intellect to the stars.
These days, planetary scientists like Jim regard the geology of Mars as crucial for understanding Earth and the other rocky planets in the Solar System – Venus and Mercury (and the moon, as well). Jim reminded me that the geologic prizes on Mars are rich. Although it is forty percent smaller than Earth, Mars’ peaks and valleys are far more extreme. The continental United States could fit nicely into one of its canyons. Its volcanoes are awesome. The largest, Olympus Mons, is more than 90,000 feet high. It would tower over Mt. Everest, and it’s large enough to occupy the state of Arizona. It is one hundred times larger than the biggest volcano on Earth; in fact, Olympus Mons is the largest mountain in the entire Solar System. Mars is a planet of geological superlatives.
Oscar levels off the Aerospatiale at 2,000 feet. Beneath us, the primeval landscape – gray and brown and black, rocky and dusty and nearly treeless – extends toward the horizon. Is this what it would be like to fly over the scarred surface of Mars? Eventually, we cross a beach, and the island of Heimaey, our stopover point, lies ahead, gradually gathering substance in the blue mist. It is a remarkably tranquil day, so calm that a limp windsock on the ground barely swivels as we veer toward the island’s tiny runway, a strip of asphalt running uphill between two volcanic peaks. Ever since leaving New York, I’ve been placing my life in the hands of complete strangers, and now, sitting beside Oscar as he casually maneuvers his small aircraft, I wonder if I’ve finally gone too far.
“Move your legs! Please!”
Oscar orders me to contract so he can freely guide us to a safe landing. The plane taxis to a standstill. We are almost there.
Jim hasn’t managed to coax NASA into funding this leg of the journey – which comes to about $300. As we slap down our plastic to pay the bill, Jim cites NASA’s “faster, better, cheaper” way of doing business to explain why we must pay the airfare to conduct scientific research. Dan Goldin, NASA’s mercurial Administrator, instituted the policy when he took over the agency in 1992. NASA, like any federal bureaucracy, has indulged in its share of waste and redundancy, and Goldin, coming out of private industry, wanted to trim the bureaucratic flab and refocus NASA. Essentially, he wanted to do more with less. He increased the number of planetary missions under the “faster-cheaper-better” regimen; instead of one expensive mission, the agency would send two, or even four cheap ones, and the returns would be correspondingly greater. And they were! But planetary exploration at any price is an exceedingly risky business, and more missions has also meant more failures. In the grip of “faster-better-cheaper,” NASA didn’t realize that the American public would fasten onto the failures of its recent missions to the Red Planet – Mars Climate Orbiter and Mars Polar Lander – and forget the successful ones. The notion that NASA was exploring the planets on the cheap and occasionally bungled the job alarmed the media, and it alarmed Congress – how could this have happened? – yet it was Congress who, year by year, imposed the budget cuts on NASA that led the agency to adopt