The Face on Mars is back! Now using data from the Mars Express orbiter, we have the above reconstruction of the site that was orginally observed by the Viking orbiter back in 1976. The lighting in the original image (as well as a few “bit errors” in the transmission of the data to Earth) made the geological feature look a little like a face, which of course caused some people to speculate that Martians built the site to resemble a face.

The whole story gets interesting on many levels. First of all, no one denies that the initial image looks like a face: people differ on the explanation, however, divided between those who attribute it to Martians and those (including me) who atrribute it to the human propensity for seeing faces everywhere. Humans have evolved to recognize faces, so our brains are built to see the pattern clearly, even when reduced to its simplest elements (think yellow smiley face).

The other thing I find interesting from a science visualization standpoint. The new Mars Express image is not a “picture” of Mars in the same way that the 1976 image is. Instead, it is a reconstruction of data taken by a stereo camera on the orbiting satellite. Basically, you can use information from multiple images taken along a single orbit to reconstruct the three-dimensional shape of the geological formation. But the image as presented is not like a point-and-shoot photo of the site.

So you can almost see where the argument that pro-Martian face-makers could go with this… The orginal image supposedly had “errors” that made it look more like a face. To make the thing look less like a face, those scientists have to resort to all kinds of fancy technical trickery! Such are the complex origins of images to which we are exposed.