Diagnosis

“I cannot go to school today,”
Said little Peggy Ann McKay.
“I have the measles and the mumps,
A gash, a rash and purple bumps.
My mouth is wet, my throat is dry,
I’m going blind in my right eye.
My tonsils are as big as rocks,
I’ve counted sixteen chicken pox
And there’s one more — that’s seventeen,
And don’t you think my face looks green?
My leg is cut — my eyes are blue –
It might be instamatic flu.
I cough and sneeze and gasp and choke,
I’m sure that my left leg is broke–
My hip hurts when I move my chin,
My belly button’s caving in,
My back is wrenched, my ankle’s sprained,
My ‘pendix pains each time it rains.
My nose is cold, my toes are numb.
I have a sliver in my thumb.
My neck is stiff, my voice is weak,
I hardly whisper when I speak.
My tongue is filling up my mouth,
I think my hair is falling out.
My elbow’s bent, my spine ain’t straight,
My temperature is one-o-eight.
My brain is shrunk, I cannot hear,
There is a hole inside my ear.
I have a hangnail, and my heart is — what?
What’s that? What’s that you say?
You say today is. . .Saturday?
G’bye, I’m going out to play!”

– Sick by Shel Silverstein

[That could just as well have been a description of little Julie -- who, unfortunately, always looked thoroughly healthy and could never get out of going to school.]

What’s the diagnosis? What does it mean? All of it; some of it; any of it?

The first quotes below are taken from a Seed review of  the book, Photography and Science, by Kelley Wilder (2009):

… One of Wilder’s most interesting points concerns the archives of scientific photographs — of stars, of landscapes, of “all aspects of human life” — that sprung up in the late 1800s. But because having a complete collection was more important than how the contents were organized or classified, these early archives were primarily holding tanks for pictures. “Creating an archive with rigorous taxonomic constraints rests on the assumption that we know what important questions to ask of that archive,” Wilder writes. “In contrast, the photographic archive of mass collections assumes that we don’t yet know what the questions are.” This idea applies to scientific archiving of all kinds even today. As we collect more data than can possibly be examined — whether it be genomic data or countless gigs of telescope observations — we are often searching for the question more than the answer and build up our archives in hopes of a wiser future.

In her last chapter on the sometimes-fractious relationship between art and science, Wilder notes that, since photographs themselves are not as virtuously mechanical as we think, making a useful photograph takes artistry as well as science. Our assumption is that a scientific photograph has not been manipulated at all, when in fact control of exposures and false color are intrinsic parts of the process. In many scientific photographs, for example, the information captured is not visible to the human eye — radio waves from the galaxy’s center, for instance, or secondary electrons from a scanning electron microscope. Scientists usually add color independent of the photographic process in order to help in their analysis and presentation of the data: Faraway nebulae are often shown in false-color, even though much of their radiation is not in the range of visible light. Likewise, cells in micrographs are often colored even though they are not large enough to scatter visible light. These manipulations can foster pervasive misunderstandings among the public about how the world really works and what science is able to illuminate. But, as Wilder notes, one of the great successes of scientific photography has been its evangelism and education on the part of science. False-color nebulae, for example, are often sold as beautiful, large-format posters.

As an example look at the “images” that come from the Chandra X-ray Obsesrvatory. This description of their transmission and processing is from Seeing the Invisible (Part 2) by Megan Watzke on The Bigger Picture blog (from the Smithsonian) June 1, 2009:

… The data that Chandra’s detectors collect are then stored onboard the spacecraft until it’s time for the telescope to make a really, really long distance phone call.

… Once the data is on the ground, it is sent by fiber optic cable to the Chandra’s Control Center in Cambridge, Mass. Once safely in hand, some standard processing is done to it. Within a matter of hours, however, the data are then sent off to the scientist who proposed to study that particular target.

Jumping to an article from Harvard, A River of Data Flows Through the CIAO Waterworks:

… While processed Chandra data that is delivered to scientists is indeed more friendly than raw binary numbers, it is generally in a tabular form that requires still further manipulation.

… In keeping with the flowing water analogy, additional processing of Chandra’s data river is akin to putting water through one side of a dam, and using it for irrigation and turbines on the other side of the dam: both irrigation and energy resources originated from the same water, but each fulfills a different purpose.

Likewise, the images, spectra, and lightcurves created from Chandra’s river of data can serve different science functions for an observed astronomical source, such as: showing its spatial size and structure, exploring how its light is composed of different wavelengths, and examining how its brightness varies with time. Answering these types of questions is what Chandra data analysis is all about. But, how does one get all that from this single table of data!?

And then back to end of the Bigger Picture blog post:

… So you can think of Chandra’s images as sort of Seurat-like X-ray pictures of space. However, Chandra’s images are not in any way imagined. The data are translated, processed and presented in such a way that make them understandable to the human eye, but they are as real as any image can be.

Don’t you just love that last bit, said without irony: “they are as real as any image can be.” I’m breaking out in a rash, just thinking about it.

-Julie

http://www.unrealnature.com/