JA Lens

Meet Kilroy

This is "Kilroy on Mars." The name references the WWII era doodle Kilroy Was Here! to which he bears a striking resemblance. However, unlike that famous graffiti this Kilroy is no mere inanimate scrawl. Captured in images taken by NASA's Mars Exploration Rover Spirit in a furtive pose remarkably like that of his name source he is our first look at an actual resident of Mars.

The fact that he can be seen crouching next to a rock roughly one meter tall in what could arguably be called one of the most interesting and iconic images ever taken of Mars is intriguing to say the least. In its original release form, before applying image enhancing tweaks, Kilroy is easily overlooked. He blends in so well with the surrounding area and its varying shades of rust, that his angular features and protected position make his presence less than obvious. Even with the image adjustments some will have a bit of difficulty in resolving this interesting individual.

You will of course notice that I have referred to him as a he and not a she or an it, this is largely for convenience and to maintain consistency with use of the masculine Kilroy and nothing more. Of course Kilroy could be just a rock. Or this could be a trick of light and shadow or it could be an example of pareidolia —that is, interpreting an inanimate object as something animate and familiar, like seeing the image of Elvis in a piece of toast or clouds that look like bunnies or dragons.

In fact, it would surprise me if there weren't a number of folks who dismiss this out of hand as being nothing more than a Rorschach test without even spending more than a few seconds here.

In that context, let me ask you to consider the following: What would it take to determine what this is? Is it a rock, a trick of light and shadow, Elvis or something actually significant? Although I suppose if it was Elvis that would certainly be significant.

While you reflect on that let me give you some more information.

Context

Located on the rim of a Martian crater referred to as Bonneville and photographed by Spirit, this boulder with or without Kilroy is featured in photos taken over a period of six sols beginning on sol 66. Sol is a term which is used throughout this site and it refers to a Martian day which is 24 hours and 37 minutes long and in the context of Spirit, it begins counting with the first day of the mission or sol 1. See here for a nice, well done summary of Mars Facts from NASA.

The task of identifying this rock in various images is made easier by its unique shape, size and surface details. The unique shape and surface details means that we can be certain of its orientation when common points of reference are fewer.

An Interesting Detail

Much of what is significant will be covered in detail later. However, let me point out something that I think is particularly fascinating:

A close examination of Kilroy reveals some remarkable and familiar features. For instance, his head appears to be mostly bald with something that resembles a small tuft hair on top not unlike what is commonly referred to as a Mohawk but I believe that this style is more accurately Pawnee in origin.

How is that for provocative?

At this point you may not see Kilroy as anything other than a rock. What to me appears as something potentially animate may to you bear no resemblance to anything remotely organic. In that, you would certainly not be alone and there is ample precedence for this point of view.

Since 2004 when NASA released the original rover images literally millions of people before you have looked at them without noticing anything out of the ordinary. Also, Kilroy was possibly overlooked by the folks at NASA as well, see It's a Conspiracy, Man... 

It has been my experience though, that people to whom I have shown this generally take a moment to process the image and are then visibly startled. As you would expect there have been exceptions to this pattern over the years. For example, when first shown one of the images one individual looked at it for about 3 seconds and said that he didn't see anything and then refused to look any closer. Another, after first denying that she saw anything, later confessed that, ok, she had actually seen him almost immediately but that if NASA hadn't said anything about it, then it didn't exist. All-righty then…

To quote Spock, "Fascinating."

A Note On Images

Many of the images here have been enhanced to increase detail and cropped to focus attention on the subject. A few have been annotated and/or illustrated. In all other respects, they have not been altered from the NASA originals. To compare the enhanced versions with their source, we have provided links to NASA's servers; e.g., marsrover.nasa.gov. [Now broken, trying to find an alternative —BAM] These links are generally provided within the text of the articles but they can also be found in greater detail in the Image Archives —see the menu above for three collections of the NASA originals.

Those of you with sharp eyes will notice a number of interesting details in the top most image. Most of this will be addressed later but one of the more obvious aberrations, though otherwise not particularly significant, includes an apparent seam just to the right of Kilroy. This is an artifact of the process used by NASA technicians to create the original panorama. They did this by stitching a number of individual frames together to create a mosaic image. The seam corresponds to the right-most edge of one of the constituent images. The small image above is cropped along its right hand border to match the original image's edge. Other images showing Kilroy lack this seam.

Since their release in 2004, they have been used in official NASA press releases which have been viewed by millions. They have been downloaded and reposted on numerous sites all over the Internet. They can be seen featured in television programs, videos and in movies which are available on DVD, Blu-ray, and on iTunes and Amazon to name just a few. They are even in a number of peer reviewed papers in top scientific journals, published in books produced by NASA and by some of the mission scientists directly involved with the MER missions. Currently, as of 2015 they have been disseminated to such an extent that they are nearly ubiquitous.

One interesting development is that once you see Kilroy, his presence in all of these places becomes so obvious.

Astronomy Picture of the Day

The picture below is the original image which inspired me to do my research and then, later to the creation of this site. This is what I saw when I fired up my browser and looked at my homepage, Astronomy Picture of the Day (APOD) on March 18, 2004. [yes, you read that right it really has been that long… I showed a few of the first images I found to a few friends and some family members in 2004 and I acquired this domain in 2007, btw.] If you look closely—ok, really closely—you can see Kilroy just to the right of center leaning on the left edge of the large light colored rock:

Despite the obvious flaw present in this particular composite image, we chose to lead with a cropped version of that panorama because we found it compelling and because NASA used it in press releases and it appeared on APOD. The seam is a detail which is easily found in the higher resolution versions of the referenced original.

What Would it Take?

There will be a tendency for some to dismiss this out of hand as just another example of pareidolia. There are many such examples of "things" on Mars that range from interesting to laughable to which we can refer.

Recall that I asked you to consider what it would take to determine what Kilroy is? Would it be sufficient to have a single blurry image of something quite small for instance. For some maybe, for me that would be a waste of time.

Consider the effect of the following on the process towards identification:

To arrive at a supportable conclusion as to what Kilroy is, whether rock, shadows, an illusion or something actually significant takes more than just a quick look (or even a long one for that matter) at a single photograph. If we had more than one image that would be significant. Having a sufficiently large number of good quality images to be able to refer to them in terms of dozens would be fantastic.

Having pictures taken from multiple points of view would be helpful. Having them taken by multiple cameras might be of use. Stereo or 3D images would be extremely beneficial. Being able to see this rock and whatever is leaning against it on multiple days would be extremely useful. The ability to demonstrate movement would be remarkable. If we could get really close and see that what was there one day was gone the next, that would be mind blowing. Having all of the above would nearly defy description.

We have all of the above.^[2]

One More Thing...

Oh, and by the way, here is another image for you to consider. I was trying to come up with a way to make Kilroy easier to see and I experimented with a number of different approaches. This is one of those attempts. I removed the color from one of the otherwise untouched press release images with the exception of Kilroy whom I left untouched and cropped it to center our interesting spectator.

What do you think, does this help?

What Comes Next

There is a great deal more to this story than I have covered here in this general introduction. The subject warrants a thorough analysis and it is best understood within the proper chronological context. Toward that end I have written a series of articles to present this from the beginning. They are numbered and follow the rover's progress from when Spirit first encounters the rock until it leaves for the nearby hills.

To continue reading go to the articles by clicking on the menu at top or click Analysis below.

Analysis

References and Notes

^[1]To quantify the dimensions of this rock I began with a search for all published papers (peer reviewed research articles, letters, reports, etc.) mentioning Bonneville crater. I then reviewed these for any mention of rock sizes. It is clear from panoramas taken at the crater rim that the subject rock was larger than other nearby rocks with the exception of one nearby darkly-colored rock. Information within the papers indicate that as rock size increases their number decreases. Working on the initial assumption that whether specified directly or not the data should reveal a high-side limit and provide an idea as to where this rock fits within the upper end of the range.

Various papers indicate a range of maximum values including 1.3 meters in diameter [Golombek, et al., 2005, 2006], "…more than 2 m in their longest dimension…" [Squyers et al., 2004] and "…at least 2.5 m in diameter at the rim." [Grant et al., 2004, 2006]. 

I examined graphs referencing rock-size frequency distributions to help determine the number and size of large rocks surveyed. [Figure 4. Golombek et al., 2005, Figure 21. Golombek et al., 2006, Figure 9. Grant et al., 2006]. It would appear that if there is a rock as large as 2.5 meters it was not included in the count. According to the graphs, most notably Figure 21. Golombek et al., 2006 showed only three rocks in the survey area that were at or in excess of 1 meter. Furthermore, there were seven rocks between .6 meters and .7 meters. Comparing this data with a review of the panorama images taken at the time, I was unable to identify any rock that appeared to be larger than the adjacent darkly-colored rock (see reference to Fig. 3 (A), Bell et al., 2004 three paragraphs below).

Rock size measurements as published were conducted manually by scientists in the following manner:

"Rocks greater than ~0.04 m in diameter were counted in roughly 70º sectors of panoramas within 10 m of the lander at Mission Success (1,089 rocks in 56.9 m² area from 0º to 76º), Legacy (426 rocks in 58 m² area from 318º to 28º) and Bonneville (689 rocks in 84.1 m² area from 255º to 353º). Rocks in the panoramas were manually identified using an interactive Graphic User Interface of RockIT, a component of the OASIS software (Onboard Autonomous Science Investigation System)³⁹. Range data were then used to calculate apparent width (1.33 times the diameter²⁸) and height." [Figure 4. Golombek et al., 2005]

Curiously, depending on the precise location of the rover during the survey our subject rock was likely not included within the area measured. However, the adjacent darkly-colored rock was measured and it is identified in a picture in Fig. 3 (A), Bell et al., 2004, as "A 77-cm-wide fractured block from sol 68 imaging near the rim of Bonneville crater." This rock appears to be roughly the same size or slightly smaller in volume than our subject rock when taking into consideration the difference in perspective due to it's greater distance from the camera lens.

The statement that this rock is roughly one meter in diameter is a conservative estimate based on available information and reflects the potential range of from .6 meters to 1.3 meters or larger.

Bell, J. F., et al. Pancam multispectral imaging results from the Spirit rover at Gusev Crater. Science 305.5685 (2004): 800-806. doi:10.1126/science.1100175

Squyres, Steven W., et al. "The Spirit rover's Athena science investigation at Gusev crater, Mars." Science 305.5685 (2004): 794-799., doi: 10.1126/science.3050794

Grant, J. A., et al (2004) Surficial deposits at Gusev crater along Spirit rover traverses, Science, 305, 807—810, doi:10.1126/science.1099849 

Grant, J. A., et al. (2006), Crater gradation in Gusev crater and Meridiani Planum, Mars, J. Geophys. Res., 111, E02S08, doi:10.1029/2005JE002465.

Golombek, M. P., et al. Assessment of Mars Exploration Rover landing site predictions. Nature 436.7047 (2005): 44-48.  doi:10.1038/nature03600

Golombek, M. P., et al. (2006), Geology of the Gusev cratered plains from the Spirit rover transverse, J. Geophys. Res., 111, E02S07, doi:10.1029/2005JE002503.

^[2]This number consists of 26 raw images, 10 panoramas (two of those being panoramic anaglyphs), a number of additional anaglyphs, one image I would classify as "other" and one very important panorama for which the underlying raw images are not available from NASA for some reason. There are also a number of additional support images of nearby interesting objects and several illustrations created by NASA designed to provide context.

As I will discuss later in greater detail, the production of color images combines three (or two) raw images taken in succession using different color filters to create one color image. Anaglyph images are created using a stereo pair, that is one image taken with the left eye and one from the right eye. Both the panoramas and the anaglyphs use these raw images in combination with many more from the surrounding area to provide useful context. Without the context, the significance or lack there of would not be as easily determined.