Images are courtesy of the European Space Agency. Yes, I'm using data from an ESA web site to discuss something that NASA did. Go figure.
The human brain is an amazing piece of engineering. Ironically, it is so complex that not even the human mind can't fully comprehend it, but significant progress has been made in decoding some of the brain's mechanical processes.
One of these processes deals with face recognition. Studies have shown that part of the brain's visual processing region, called the fusiform gyrus, is responsible recognizing and categorizing visual information. A specific area in the fusiform gyrus, known as the fusiform face area, seems to be responsible for recognizing human faces. Other studies have shown that this ability is already functioning at birth. Such mechanisms are essential for our survival, and most tend to stick with us throughout our lives.
And that's a good thing. Imagine what life would be like if you couldn't recognize friends, family, or even yourself. Unfortunately, there is such a condition. It's called prosopagnosia, and may involve damage to the fusiform face area.
Conversely, we often recognize faces where there are none. Pareidolia is a phenomenon where we see images and faces in things that are not related to the things we perceive. For example, most of us have recognized the shape of an animal or other thing in a cloud.
This ability has its advantages. It permits us to see through camouflage, pick out faces from a crowd, and produce interesting art.
But, it can easily be carried too far.
Take for example, the infamous Face on Mars.
While taking pictures of potential landing sites in 1976, the Viking 1 probe imaged the Cydonia region of Mars. One of the more intriguing features was a mesa that resembled a human face. As soon as the image became public people began to claim that the image was an artificial construction. It was hard to argue against what the eye was perceiving, though, until NASA was able to get higher resolution images nearly 25 years later.
I thought it might make an interesting exercise to show how the real feature can be mistaken for something that it's not, when the conditions are right.
First, here is the original Viking 1 image from 1976:
Yes, it's small. Actually, I think this is a slightly enlarged version of the original image. The resolution was very low--somewhere in the order of 150 to 300 meters per pixel. The pixels represent two types of things: luminance data, and missing data. Luminance data represents the brightness of the surface being imaged. Combine luminance pixels together and you get a black-and-white image. The missing data is just that: pixels that were lost in transmission.
Below is an image from the Mars Global Surveyor (MGS). This one has been scaled down to save space. A larger version is available here.
Big difference, huh? Well, the resolution of this image is MUCH higher, and the image was taken when the sun was higher in Cydonia's sky. It's still easy to see some parts of the face in the image, but, in my opinion, it certainly doesn't look as much like a face as the Viking 1 image.
For my little exercise, I reduced the MGS image to approximately the same size as the Viking 1 image:
Next, I simulated the shadows from the Viking 1 images by adjusting the contrast:
I thought that the image still had too much detail, so I blurred it a little:
Finally, I attempted to identify the missing pixels on the Viking 1 image and apply them to this image. This gives the face its right "nostril:"
OK, maybe it's not as impressive as the original Viking 1 image, but I think it still proves my point that it is easy to mistake one thing for another.
And this phenomenon isn't limited to just the "I-know-what-I-saw" and the I Want to Believe crowds. Famed astronomer Percival Lowell was convinced that there were canals--and therefore an advanced civilization--on Mars. And more recently one of my favorite astronomers thought he saw the ghost of Lenin on his shower curtain. (OK, not really, but it sounds funnier that way.)
Still, despite the evidence, some people cling to the idea that the Face on Mars was made by some intelligent force. I admit its more fun to believe in space aliens, fairies, and that Andy Kaufman and Elvis are still alive. But, there are times when we need to face facts and move forward--and hanging onto a fantasy doesn't do anyone any good.
I think, instead, that we should focus our energy on finding out who or what created these interesting Martian features:
http://apod.nasa.gov/apod/ap990315.html
http://www.planetary.org/blog/article/00001314/
