Tag Archives: mars express

Mars versus HTML

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What started out as an impassioned diatribe turns out to be a mere complaint about HTML…

I get press releases in my email. They have URLs. I follow those URLs and (once in a while) end up writing about the press releases on my blog. So, this morning, I received “ESA: Mars Express watches a dust storm engulf Mars,” which pointed me to a page on the ESA site that featured the three images above, inset at different points in the article, and described (from left to right) as, “a dust storm on Mars,” “temperatures in the Martian atmosphere,” and “Mars – thermal radiation spectra.” I clicked on the wee pictures, hoping to be linked to something—nada—and looked for a link to a page of graphics that might offer some explanation—nada y nada y nada.

My ire began to build. That’s an artist’s conception of a dust storm, not an actual image! It should be labelled as such! And those graphs, lacking any axes, any interpretation? Argh! Then I noticed the URL. “SEMPWD361AF_index_2.html”? Hmmm. I changed the “2” to a ”1,” and lo and behold,… A whole page about the images.

Then I remembered the typical ESA page-naming scheme. I changed the “1” to a ”0” and found exactly what I expected in the first place.

So what can I say now? Other than recommend the email notices include the top-level ”index_0.html” link? Well, I think the caption for the animated dust storm should clearly say “artist’s rendition.” And the abscissas in the temperature plot should match. Otherwise, I guess I just have to get started with my day…

High-Resolution Abstract Art

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Having blogged remote sensing on Earth in my last post, I guess I should make the leap to remote sensing on Mars…

So, what annoys me about the way the press release describes the above image is that, although the story is “the highest-resolution camera ever to orbit Mars,” the reader is given no sense of scale. You have to go to the caption on the mission webpage to find out that the resolution is about a foot per pixel. If nothing else, the press release could indicate the size of something in the image—for example, the small crater in the lower right-hand corner is about 15 feet across (I checked).

To be honest, I’d like to see a graphic scale on the image, marking out a distance of, say, 100 feet. But that ruins the aesthetic that has started to develop around NASA images. Images from the rovers have their own appeal, but the Mars orbiters send back images that function more as abstract art (take, for example, the Mars Express image of Aureum Chaos). A little scale in the corner of the image would ruin that. I have in mind Elizabeth Kessler’s thesis about Hubble images and their relationship to American culture as I write this.

Mars Facial Reconstruction

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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.