Monthly Archives: September 2006

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.

Mud Volcano

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Okay, I’m an American, so no one would expect me to remain current in international events, but what’s with this “mud volcano” in Java? The images above come from the Centre for Remote Imaging, Sensing and Processing, which offers web page with a (must admit) spiffy viewer to examine the extent of the damage.

To me, the above images represent the power of remote sensing and our new-found ability to contextualize terrestrial events (cf. the extensive use of such imagery in Al Gore’s impressively illustrated An Inconvenient Truth).

Just bizarre. Listening to a bunch of talks at the recent Pale Blue Dot meeting convinced me that I really don’t understand geology, and this just confirms my suspicion…

Uranus in Season

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Hubble just announced the discovery of a dark cloud in the atmosphere of Uranus, but as I looked at the press-release image, I realized that I was seeing Uranus from a slightly different angle compared to previous images. So I created the composite image above, using the various Hubble pictures of Uranus from 1994 through 2006. The Hubble crew did much the same thing with Saturn a few years ago, so it’s not an original idea. But it’s kinda kewl to see Uranus going through 14% of its orbit.

Sonar or Later

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Several sources are reporting on the discovery of the remains of the U.S.S. Macon, one of the last dirigibles flown by the United States, which foundered and sank near Point Sur in the Pacific Ocean back in 1935. A webpage on the Monterey Bay Aquarium site describes the research project nicely—including an intriguing detective story (involving a girder and a seafood restaurant) and the plans to return to the site this month for further exploration.

It takes a little digging to find the image above, which is probably a good thing, since it’s not the easiest to interpret… It’s a sonar image that shows the track of the scanning device as a vertical white line on the left, with the debris field showing up as a mottled patch on the right of the image. The U.S.G.S. offers a good description of side scan sonar techniques, including a spiffy diagram at the top of the page that should make the above image somewhat more comprehensible.

Images like this one come in handy, however, when trying to describe the challenges of scientific discovery. Part of the detective story that doesn’t show up on the website is how you take miles and miles of scans like the one above and sift through them to determine the location of interesting stuff—remains of an early-20th-century airship, for example. The astronomical community will face just such a challenge in the near future, when the Large Synoptic Survey Telescope (LSST) comes online with several terabytes of imagery collected every day. How does one sift through so much data to find interesting events? And how does one convey the magnitude of that effort to the general public?

By the way, you may actually recognize the U.S.S. Macon from the famous picture of a dirigible over New York Harbor. That’s her! With Manhattan stretching out in the distance…

From Mice to Magnetospheres

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A coworker just asked me a question about the magnetosphere, and in a quick online check, I came across the above image. I tend toward the nit-picky in matters concerning space weather, in large part because I attended a graduate program in “Space Physics and Astronomy” at Rice University. I see several problems with this image… Most disconcertingly, it makes the bow shock appear like a nearly solid boundary, with the interior and exterior vastly different in their texture and color; in fact, the bow shock simply represents the location where particles slow from supersonic (yes, there is a such a thing as sound speed in space). Furthermore, the little squiggly arrows presumably indicating particle motion through the magnetosheath look nothing like the actual flow. Finally Earth’s magnetic field should look more like a dipole, so all the field lines should not converge to a single point at the poles.

For contrast, allow me to reproduce a scene from the most recent space show produced by my institution, Cosmic Collisions:

We used data from the Center for Integrated Space Weather Modeling as the basis for the sequence, so the effect is not quite so diagrammatic. The grey surface represents the bow shock; the bluish surface represents the exterior of the region dominated by Earth’s magnetic field. And note that the flow moves through the bow shock and around the Earth’s magnetic field. You can see more from the show (and more of the data) in a short piece produced for our “Science Bulletins” AstroViz segment.

Finally, speaking of alma maters, a space weather story from Cornell just appeared in my inbox. Solar flares may cause problems with GPS receivers—no great shakes if you’re driving your Lexus down I-10, but more problematic if you’re flying through dense fog on a commuter jet.

Mouse Brains!

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I am far too queasy ever to dissect a mouse; that’s why I went into the physical sciences. That’s also why I appreciate tools that allow me to experience biology from the comfort of my desktop.

I took the above snapshot from the “Brain Explorer” program available (for both Windows and Macintosh) from the Allen Institute for Brain Science. It shows (what else?) the structure of a mouse’s brain. Turns out the little critters, inbred as they are, display little variation in their brains’s structures, making them easy to compare to one another.

So you’ve got your 3-D model of the rodent’s brain. After loading a gene database into the Brain Explorer, one can rotate around the structure, displaying the loci of activity for the gene as well as adding or subtracting 3-D overlays (or 2-D slices) that show different parts of the brain. Fiddling with the software made me think about how novices must react to the Digital Universe data and software that my institution makes available: ignorance of the underlying science makes it rather enjoyable to fly around, but I don’t think I’m extracting much useful information from the experience.

Of course, I’m not the audience for the software. In a story that appeared in today’s New York Times “Science Times” section (rapidly picked up by Reuters, too), several brain researchers interviewed claimed that the resource is of remarkable value to their community. Complemented with some supporting material (as we do with our atlas of the Universe), it might make a fascinating tool for students or even interested aficiandos.

On the Allen Brain Atlas site, more sophisticated 2-D tools are available to analyze the existing data.

Photographic (Quantum) Loops

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The image above represents “loop quantum gravity,” selected somewhat arbitrarily from Carlo Rovelli’s website. The inspiration for this image choice came from a lecture held at the Hayden Planetarium just last night. Lee Smolin showed up to promote his new book, The Trouble with Physics, which I will admit up front I have not read (although a copy now sits in my office, waiting for my attentions).

The use of a photographic subject to illustrate a highly abstract concept intrigues me greatly. In contrast to the award-winning attempt to make a tremendous amount of data look photographic, we have here a photograph attempting to make a tremendously complex concept look real. Furthermore, Rovelli offers the image (and another) effectively without comment, stating only that it gives “an intuitive picture of the ‘loopy’ structure of space predicted by loop quantum gravity at very short scale.” Hmmm.

The problem with expecting intuition when confronted with an image—particularly an image intended to function essentially as a metaphor—is that intuition is a hard-won and highly specialized skill. Personally, my intuition on astronomical imagery is quite respectable; on physics, pretty decent; on biology, almost non-existent. So the message that I will extract from Rovelli’s images differs tremendously from his own reaction, I’m certain, and a layperson’s response could have little or nothing to do with the specialists’ interpretation.

Smolin’s lecture (and presumably his book) suggested that physics needs to go back to its experimental roots, reconnecting highly-complex concepts to observable events, such as gamma-ray bursts, that could provide a real-world (or -universe) evidence for esoteric theories. A podcast of the lecture is scheduled to appear on Seed magazine’s website in the not-too-distant future. Keep your eyes (and Internet connections) peeled!

The Way of the Dodo

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Like many research organizations, the Royal Society has a “Picture of the Month” that it displays on its web page. This month, they reproduce the image above, a 19th-century lithograph based on a 17th-century oil by Roelandt Savery. I would like to draw your attention to a critical attribute of this lithograph: it sucks. Particularly if you have no idea what a dodo looks like.

Comparing the above image to Savery’s most famous oil of a dodo, it seems as though the 19th-century copyist (somebody named “Erxleben”) may simply have lacked talent. Admittedly, the caption on the web site indicates that it merely reproduces “a small detail” of the lithograph, but even at that, it’s hard to take the person’s skill seriously.

I choose this image to highlight how far we’ve come. Three-dimensional computer reconstructions and digital images from spacecraft a billion miles from home are only the tip of the iceberg! We have a plethora of techniques to take scientific data and transform them into pictures. But the work started with scientists and artists putting pencil to paper, or brush to canvas, or crayon to limestone,… Photography, of course, only started in the middle of the 19th Century, and digital imaging techniques are thirty-some-odd-years old.

What we now take for granted is the fidelity of a representation to its sources. Specialists might quibble over the use of color or the “fixing” of errors such as bad pixels, but fundamentally, we all think of contemporary visualizations as accurate in a way that few drawings or paintings, even those executed by gifted artists, could ever hope to be. When you couple that inherent limitation with the potentially incompetent skills of a secondary or tertiary artist such as, say, Erxleben, then you quickly see how successive copies of a work used to grow worse over time. (For another good example, compare Galileo’s orginal delicate watercolors of moon phases with the respectable engravings he commissioned for Siderius Nuncius as well as the mediocre woodcuts that appeared in a knock-off, unauthorized printing of the same.) We no longer need to worry about such things.

Of course, there are plenty of other things for science visualizers to worry about (or at least consider and mull over). That’s why I started this blog, after all…

Visualization Challenge

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The National Science Foundation and Science magazine sponsor an annual “Visualization Challenge,” and you can see this year’s first place winner in the photography category above. What I find interesting about the choice is that this image is not a photograph at all: it’s actually a two-dimensional representation of a three-dimensional reconstruction, pieced together from some 60,000 200-micron-thin scans of the mummified remains. For purposes of the competition, the photography category includes “film or digital photographs and photomicrographs, as well as images obtained from electron microscopes, STMs, AFMs, telescopes and similar instruments,“ which is even more simply defined as “images created by sensors.” A rather expansive definition…

Other winning images and multimedia pieces can be seen in a slide show from Science magazine or on a web page at the NSF site. Interestingly, no astronomy visuals appear in the winning entries.

I worked on a piece that garnered attention in the very first Science & Engineering Visualization Challenge, and with our most recent show in the can, perhaps we will enter again next year. Until then, the 2006 winners offer some pretty delightful imagery—I particularly like the visualization of air traffic over the United States.

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.