I suspect many readers will agree that the highlighted feature at least resembles a humanoid eye, down to the well-defined elliptical structure surrounding the central protruding "pupil." But how do we go about testing the notion that the Face on Mars boasts an anatomically accurate "eye"? After all, aren't we merely seeing what we want to see?

In this case, no.

Long before the Mars Global Surveyor spacecraft returned provocative images of the Cydonia Mensae region of Mars, the presence of secondary facial characteristics had been predicted by proponents of what became known as the Artificiality Hypothesis. It seemed likely that the Face, if the work of intelligence, would betray traces of anthropomorphic detail when imaged by better cameras. (The "eye" was only barely visible in the best of the early Viking photos from the 1970s; certainly little or nothing about its shape or structure could be inferred.) So when the first overhead images of the Face became available, the presence of a seemingly well-preserved "eye" became apparent vindication for proponents of artificiality on Mars. After all, it had been predicted by a testable hypothesis. Other "secondary" features were noted as well: lip-like structures that defined a broad, parted "mouth," candidate "nostrils" and others.

While none of these features proved that the Face was the work of extraterrestrial intelligence -- let alone the subject of a far-reaching NASA cover-up -- they pointed to the possibility that the Face (and perhaps other anomalies in its vicinity) were more than the "tricks of light" as maintained by NASA's public relations personnel. (To date, NASA has yet to conduct a scientific investigation that would bear out its contention that the features in Cydonia are wholly natural -- an undertaking that might reasonably include the expertise of archaeologists familiar with the role of remote sensing in detecting potential sites here on Earth.)

And so we remain inoculated to the presence of the truly mysterious. The recent "Martian" found in a 2004 rover image has garnered surprisingly intense (if generally dismissive) attention from both independent bloggers and a condescending mainstream media. Meanwhile, the enigmas in Cydonia go conspicuously unremarked, dismissed as the stuff of wishful thinking or the stalwart dreams of conspiracy-mongers.

But this doesn't have to continue -- unless, of course, we let it. As I write, NASA's Mars Reconnaissance Orbiter and the European Space Agency's Mars Express spacecraft circle the Red Planet. Both wield stunning instruments that could easily be trained at Cydonia, regardless of what ultimately awaits us there. Noisy "conspiracy" claims aside, the presence of possible archaeological sites on Mars is scientifically testable -- but in order to arrive at a meaningful conclusion we must cast away a host of entrenched preconceptions, regardless how attractive they might seem to an academic community weaned on the certainty that humans have always occupied a central role in the history of our solar system. (To be sure, the very presence of a human-looking visage on Mars smacks of the pervasive "will to believe" that's infected so many astronomical inquiries throughout history, from the casual certainty of a geocentric cosmos to the illusory "canals" of Percival Lowell.)

The Face on Mars is not dead. We can continue parroting the "answers" offered by self-proclaimed skeptics or we can proceed with objectivity, caution and the knowledge that reality is seldom as abiding as we'd prefer.