Searching for nonfractal signatures

The search for artifacts on other planets is by no means limited to "seeing faces." Aside from calling on archaeologists when confronted with anomalous surface formations, mission planners can test spacecraft images for telltale "nonfractal" terrain signatures.

Geological processes are inherently fractal. Unlike artificial sites such as cities and farms, defined by uniformity and harsh angles, natural landscapes repeat themselves on multiple levels. A mountain, for instance, is "repeated" in any of the countless rocks that litter its slopes. (Weirdly enough, we seem to inhabit a massive fractal: orbiting planets recall the structure of atoms; galaxies themselves bear a passing structural similarity to their constituent star systems.)





As part of a long-running "debunking" campaign, Malin Space Science Systems (the camera subcontractor for NASA's Mars exploration program) has popularized the so-called "Happy Face Crater," a feature often cited to defuse discussion of the more robustly detailed Cydonia Face. Consisting of a crater basin with attendant debris in the shape of a crude smile, there doesn't appear to be anything truly anomalous about the Happy Face. But subjecting the crater to an impartial scan in order to ascertain its fractal signature would go a long way toward arriving at an objective conclusion.

Is the Happy Face more or less fractal than its neighboring craters? Better yet, how would it stack up to the better-known Face in Cydonia?

Intrigued by the potential of fractal algorithms to deduce artificial constructions, image processor Mark Carlotto tested images of the Cydonia region. The Face registered suspiciously high, as did another contested feature. Since Carlotto's computer algorithm wasn't designed to seek out faces, the Face's conspicuous nonfractal signature offered a quantitative argument favoring an artificial origin.

Carlotto's enticing proof-of-concept has yet to be embraced by the space science community. Indeed, Carlotto himself has yet to put newer images of Cydonia to the test. But given the computing might of today's desktop systems, it's not unrealistic to imagine a committed search for anomalous fractal signatures on distant planetary surfaces. What do we have to lose?

This piece originally appeared at aboutSETI.com.