Thursday, February 28, 2008

My meteorwrong

kw: information, space science, meteorites

Proving myself wrong about a rock

I've carried this rock around for so many years I've forgotten where I found it. I suspect, though, it was on a trip to San Benito County, California, with a group of fellow Geology students looking at the ultramafic rocks there.

"Ultramafic" refers to rocks with high Magnesium and Iron content; the County is host to a sequence of rocks derived from the upper part of the Mantle during a continental collision.

The connection of this rock with that trip is only in retrospect. Since finding the rock in a box several years ago, I've considered it might be a meteorite, mainly because it is rather heavy and sort of "looks right". Recently I decided to find out.

I decided to first measure its density. I don't have lab equipment available, so I used what I found in the kitchen: a spice scale (capacity 0.5kg) and a 0.5 liter measuring cup. I weighed the stone (210g), then put the stone in the cup and added water until it was covered, turned it all ways with a spoon to knock off all bubbles, then topped it to 500cc, the top line on the cup. I fished out the stone and read "a little below 450", which I estimated as just above 440cc. So the difference was less than 60cc, and I called it 58-to-60cc. Divide these limits into 210, and the result is 3.5-3.6 g/cc. That's in the right range for a stony-iron meteorite.

Checking relative accuracy, I decided I wasn't quite satisfied. The scale is marked each 10g, and can be read to 5g with care, so 210±5 meant a range of ±2.3%. The measuring cup, however, is only marked each 50cc, and it is hard to read a fifth of a marking, particularly because their spacing changes on the tapered cup. Generously assuming I can read to 10cc accurately, I still was faced with a range of ±10cc out of about sixty, or about ±17%. And there's no telling how properly printed the markings are...

So I used weight instead of volume. I tied a thread harness to the rock, so it would hang flat. I put the rock into the cup with enough water to cover it when I lifted it clear of the bottom. The whole rig exceeded the capacity of the scale, but not when I lifted the rock above the bottom of the cup, yet still under the water. I could just make it: 490 grams. Then I lifted the rock all the way out, and the reading dropped to, as nearly as I could tell, between 435cc and 440cc. I split the difference at 52.5±2.5cc, an error figure of ±4.8%. Now we're getting somewhere.

The result was 4.0g/cc, ±5.3%, or a range from 3.8-4.2. The former measurement, 3.55 with a ±17% range, covers a possible span of 2.9-4.2! Anyway, it doesn't contradict the new measurement. Now...what has a density of 4?

Stony meteorites have a density in the range 3.0-3.3. Iron ones are near 8, and even stony-iron ones are typically less than 3.8. My stone is either too heavy or too light to be a meteorite, and is not magnetic, so stony-iron is out. A closer look provides a further clue.

This broken surface, which is in the shadow to the left of the first photo, shows holes inside the rock.

A quick look at the Meteorite Realities page confirmed my suspicion that no meteorite formed with internal holes; there is no gas in space to open the holes, and these are clearly gas bubble holes. Though they appear to constitute only a few percent of the rock, they indicate that the bulk density without porosity ought to be several percent greater, at least 4.2-4.4 g/c. Now I'm in trouble...

The rounded lump at the arrow is reddish compared to the solidly gray background. Is it a garnet? Perhaps the garnet (or whatever) is one of the denser types, but it has to constitute most of the rock to have much effect. The usual sort of garnet peridotite seldom exceeds a density of 3.5, and this rock isn't green enough to be a peridotite (think the black sands of Hawaii, which are really blackish green, formed of peridot sand).

This image, around the end of the stone from the other two views, shows a squarish, reddish crystal (see the arrow). Maybe a garnet, or possibly a spinel. The reddish stain below gave me another clue, and there are several around the stone (see the first image). Now I remembered that trip to San Benito. I still don't know if that is where I got the rock, because we also visited a number of mines on that trip and later ones during my Senior year as a Geology student.

What is clear is that this is a combination of garnet or spinel in a siderite-hematite mix. These occur together in metamorphic assemblages, and both San Benito County and other places I frequented in those years were metamorphic terranes with plenty of sources for iron ore, which is just what this is.

Tuesday, February 26, 2008

An Ender Sidebar

kw: book reviews, science fiction, space fiction, political fiction

Testing limits is a process of crossing them repeatedly, in both directions. So-called "cross-genre" or "multi-genre" writers are really limits testers, Orson Scott Card exemplifies the breed. His "Ender" series (two disparate series), while appearing as military space fiction, is really political fiction in a space setting. Once you have read most of them, you realize that Ender and his brother Peter are mirror images: almost identical but with a twist. The "Alvin Maker" series, ostensibly magical realism, is psychological exploration, as is the "Homecoming" series. I have read none from his other series.

But as I read A War of Gifts, a novelette in the Ender series, I found myself wondering, not for the first time, "Why are Card's positive protagonists so neurotic?" Sometimes it reminds me of my favorite neurotic writer, Isaac Asimov, who was also a limits-explorer, one who cut his writer's teeth on robots exploring the universe of the "Three Laws". Asimov identified with his robots to the point that, when in late life he brought together the "Robots" and the "Foundation" series, he made his favorite robot into a god. He'd been working up to that for decades, most notably with "Bicentennial Man", who became human rather than divine..."a little lower than God" to quote the Psalmist.

But we were talking about Card. Is he as neurotic as Asimov? Having lived among Mormons, I don't automatically label them crazy at the outset, and I don't think so here. Rather, Card is more consciously exploring limits than many others.

This offering is about offerings, or Christmas gifts, to be precise. It begins with a most painful caricature of pseudo-Christian fanaticism, and I almost put it down at that point. Fortunately, Card is wise enough, and knows the Bible well enough, to expose the falseness of this particular sect while maintaining the integrity of faith in general.

What I found fascinating was not the rebellion of a space-bound mini-world full of brilliant children against their military mentors. Rather, it was the very adult attitudes of two of them, Dink Meeker and Andrew (Ender) Wiggins, though they are presumably in the 8-10 age range. I've been fortunate to spend time with some of the brightest kids around, the kind that need a special IQ test to find out they are 180 or so (It's energizing and exhausting, as I limp along with a mere 160). Though they have remarkable stability and focus, they are still children, and I find the children depicted in A War of Gifts rather incredible.

But the story, as all of Card's are, is a story of redemption, and this being the "Ender" universe, it is Ender who must be the suffering redeemer. Sobeit.

A closing word on the use of "Spare the rod and spoil the child" and "beat your son with a rod, and you will save his soul from hell." These word were written by Solomon. Do you know who Solomon's older half-brothers were? Amnon, who raped his half-sister Tamar, and Absalom, Tamar's full brother, who murdered Amnon and later rebelled, driving his father David the king, from Jerusalem. The Bible story makes it clear that Absalom went to hell, and the familiar Proverbs are Solomon's exaggerated rebuke of his dead father David for being one "who never asked his sons, 'Why have you done this?'."

Parents! Do Not use these verses in Proverbs as justification to beat your children!! There are much better ways to correct and discipline a child. Do not teach them that you believe violence solves anything. You just make them more prone to violence themselves.

Monday, February 25, 2008

Doom of a Hero

kw: book reviews, nonfiction, biographies, medicine, aviation

When I saw the title, The Immortalists, I expected a book about the work of people such as Robert Ettinger, author of The Prospect of Immortality (1962). Ettinger was a pioneer in cryonic preservation (both his wives are on ice; he still lives at age 90 as of this writing. He leaves the discovery of resuscitation and repair techniques to future scientists).

What I found was quite different. In The Immortalists: Charles Lindbergh, Dr. Alexis Carrel, and their Daring Quest to Live Forever author David M. Friedman brings us a double biography. Lindbergh was the most beloved hero of the early 1900s, later a much-maligned antiwar spokesman, and much later returned to hero status. Carrel was a Nobel-winning surgeon who became first beloved then hated for his pro-eugenic speaking and writing, and who remains controversial since his death in 1944.

By the midpoint of the book, just before the monochrome plates, I knew all I wanted to about "Lucky Lindy", and much more than I cared to about Dr. Carrel. The aviator-become-bioscience researcher was not just "Lucky": He was one of the most gifted mechanical engineers of his day. He was also a sharp avionic investigator who early judged that the German air force was capable of taking on the whole world and winning. His judgment proved mostly correct, but he had been hoodwinked as to the range of their bombers.

The Doctor was, as judged by examples of his own writing, a monster. To be fair, I looked outside the book for further quotes, and my first impression was upheld. He was a bigoted advocate of "the white man's burden" and an anti-Semite. Yet his bigotry was not without relief, and he saw a need for "the right kind of Jews" to leaven a populace.

His influence on Lindbergh was almost beyond belief. Every sociological notion of Carrel's was emphasized and exaggerated in Lindy. Carrel had said of him, defending his employment of the aviator to make equipment for medical experiments, " who achieve great things in one area are capable of great accomplishments in all domains." (p 78) We have many examples of how tragically wrong such a notion is, but in this case, Lindbergh did happen to be a marvelously capable technician.

He was, however, pretty blind socially. The author remarks at one point, "...Charles Lindbergh was less interested in people than in machines." (p 105) He remained strongly anti-Semitic and anti-"colored" until quite late in life. Thankfully, he did moderate his views quite a lot around 1970.

Carrel started out a moderate bigot and stayed that way. In his book Man, the Unknown he advocated a super-priesthood, an "Academy of man" to tell everyone else what to do...or else. A large step beyond Plato's Republic. He is thought to have carried out some of the French eugenic experiments that occurred after his return to France in 1939, but I can't find solid evidence either way. But any supportive truck with the Vichy government tars him, in my view. It is his involvment in the underground French Resistance that partly redeems him.

Lindbergh and Carrel collaborated for about a decade on equipment and techniques intended to keep organs alive outside the body. Perhaps damaged or diseased organs could be repaired while artificial or temporarily transplanted organs took their place. Perfusion pumps made by Lindbergh were a key to these experiments.

Lindy's pumps were based on, and greatly improved upon, a mechanism by which Dr. Carrel kept a piece of chicken heart alive and throbbing for more than twenty years. It was learned decades later that the tissue was continually replenished because of stray heart cells in the serum that bathed it, which was frequently topped up with fresh preparations. Heart muscle cells and some stem cells would incorporate into the lump, replacing cells that died off, then multiplying as needed. Probably, the last original cell died out in the seventh or eighth year. Chicken heart cells have a natural lifetime of about five years. This was not deliberate deception on Carrel's part; he didn't know it was happening.

The aim of these experiments was physical immortality. During a soul-searching time in Utah, Lindbergh thought, "If man could learn to fly,...why could he not learn how to live forever?" (p 21, quoted from Autobiography of Values, 1977) Only since 1990 have we learned how misguided the experiments were. Once genuine life-extension technology is actually developed (if ever), even today's foolish experiments with stem cells will seem equally mistaken.

Friedman is a good writer, but he had a tough couple of subjects. I confess I skimmed over quite a bit in the second half. I did find one bit of comfort in it all. The "boomers" aren't the first generation to bridle against the strictures of mortality...just the richest.

Sunday, February 24, 2008

Most faithful friend image gallery

kw: book reviews, nonfiction, photos, dogs

Dogs by Catherine Johnson, with a few words by William Wegman and others, needs few words. It barely has a thousand words itself. Ms Johnson, not the author of this book but its collector, has collected photos of dogs, mainly family pix with dogs in them, all her life. She shares the best of her collection with us. Here are a couple examples, one showing the format of the quotes about dogs, to be found on about one page in ten.

There's no telling what page number these are found on; the pages aren't numbered. This is a photo album after all, and do you number the pages in your photo album? If you've read the prior two posts, you now know the origin of the image I used as an example.

Saturday, February 23, 2008

A Descreening follow-up

kw: instructions, images, tools

Trust a spate of writing to get the juices flowing! After writing the prior post, I tinkered around a bit with the scanner. I found some better settings and procedures.

Most scanners have a Twain or similar driver screen, and an Advanced mode, where you'll find color tuning and various filtering operations such as Unsharp Masking, often including Descreening. Preview runs fast, so I could pre-outline the area to scan (my older scanner did this more "up front", it took until today to find it in the new one). After setting the area desired, Zoom lets you refine it if needed (an example appears later).

I Previewed the image of the girl and her dogs and Selected just that area, set 150 dpi for final output, and then clicked Descreen and Scan.

First, these clips illustrate the differences between the automatic method and my multi-step "hand" method (you can jump down and skim the prior article—or click here if you're viewing single posts; use Back to return—to get familiar with the method).

The clips, as before, have the corner of the girl's mouth at the upper right. The 30x30 shown here is the result of Auto-Descreening, and the 120x120 is a 4x resize to see the pixels. The two clips below it show the result of my 5- or 6-step method, which begins with a scan, unfiltered, at 600 dpi. The result of either method is an image with 150 dpi resolution, and the halftone dots and their Moiré pattern removed.

The unsharpened version is closest to the Auto result, but a little inferior. The sharpened version has more visual interest for me, but take a look at the white dot in the lower-right clip, on the girl's neck near the collar. That may be real, but he faint ring around it is a sharpening artifact. To my judgment, the Auto process gave slightly better results.

This is the full image of the picture from the book. It is very nearly the same physical size on my screen as the picture in the book (its size on your monitor will depend on its own dpi). Click on the image to see all that its 150 dpi resolution can show. Blogger limits images to about 400 dots vertically, and the 150 dpi image is 752 dots tall. It will slightly overfill the browser window (or the left half of it) on a 1024x768 screen.

This points up a practical matter. No matter how nice your original image is, if you are going to use it in a blog be sure it looks "pretty good" at that size. I once had a graphic with lots of details, and the lines were so thin, they mostly vanished. I had to redraft it and simplify it. It just wouldn't do to say, "Click on this critter to see it better...sorry for the mess you see right now".

So, after all the Sturm und Drang, I've obtained as good a copy of the book's photo as technology (that I can afford) currently allows. I decided to try a full-color picture from a magazine. I needed something small...

I happened to have a recent issue of AARP The Magazine around, and saw an article by Dr. Andrew Weil, with his image in the byline. This is the Preview/Zoom screen view of an early stage in capturing a picture of Dr. Weil. A small (¾ x 1 inch) face-photo accompanies his articles in many venues. The halftone dots are quite clear, particularly around the eyes.

This image is about what you'd see in a raw 300 dpi scan. The larger one that a click will reveal is close to 360 dpi. This is a screen capture image, and its resolution depends on the way the scanner driver runs its Zoom routine.

I had two ways I could proceed. I first used the Auto-Descreen from the scanner, then I loaded the screen capture image and, without any blurring at all, resized it to 0.24 to match the 150 dpi image (it has a boundary the other image doesn't have.) I used the Lanczos filter for resizing, the slowest and best filter offered in IrfanView.

The small image on the left is the Auto-Descreened result. It is very good. The other is the shrunken screen capture shot. There is a bit more background noise, but to a quick glance, the images are very similar in quality.

I reckon I'll keep fooling around with hand descreening, but I've determined the Twain driver does a fine job, and I'm switching to it for production.

Friday, February 22, 2008

Descreening with IrfanView

kw: instructions, images, tools

OK, if you like to edit digital photos, then before you go any further, go to / and download IrfanView. I use it almost daily.

A book I'll soon review contains mostly photos. In the past, I've used scanned photos in the blog, and I did a lot of work on them for viewing on the computer. My scanner has a "descreen" option, but I found I could use a few steps in IrfanView and get a better result. The following procedure is to completely descreen an image scanned from a halftone print. The example image is a 2-tone Sepia-toned reproduction of an old photo, but the method is the same for monotone or full color.

Halftone on glossy pages such as a magazine or photo-oriented book has from one to four (sometimes seven) hexagonal dot patterns with a pitch of 120 to 180 dots per inch; 150 dpi is most common at present. Halftone on newspaper pages and other non-shiny paper has a pitch of 80 to 120 dpi; 100 dpi is most common. There is a whole discipline of picking the angles for the different screens so they won't produce unsightly Moiré patterns (interference banding). So it makes no sense to try for a final image with more than 100 or 150 dots per inch.

To descreen, one must begin with lots of resolution; much of it will be discarded in stages, but it is needed at first. I scan at 600 dpi. This seemingly large image is a 1.33x1.75 inch clip from a larger image on the book's page. At 600 dpi, full size is 797x1039 pixels.

This 120x120 clip from the image, with a corner of the girl's mouth at upper right, shows the halftone pattern well. If you click on the larger image, you'll see the pattern over the whole image when it is shown at full size. The "circly" pattern is a very small moiré pattern of the black and brown screens overlaid at an angle (I think it is 37°). This amount of interference cannot be avoided.

Of course, the "proper" way to descreen such an image is to use Fourier series filtering. It doesn't simply remove all frequencies higher than, say, 80 dpi; it removes the specific frequencies that pertain to the screen patterns, leaving some extra photo detail visible. It is thus better than both the descreen routine in my scanner and this procedure, but for most purposes our process will be sufficient. Those with the extra energy can get Fourier analysis doesn't come cheap or easy.

The first step is to do a basic, full blur. In IrfanView I enter Ctrl+E (Menu Image/Effects/Effects browser...), select the Blur item and set the amount to 99. This causes complete mixing within a 1-pixel range. If you look carefully at this image, it has a smoother look.

This 120x120 clip shows that it is indeed smoother, the photo details look good, but some halftone remains.

For many purposes you can reduce this image to ¼ size so it is displayed at 150 dpi (or 50% larger than "life" on a 100 dpi monitor and 2x on a 75 dpi older monitor). In IrfanView, Ctrl+R (Menu Image/Resize) selects Resize where you can single-click a half-size reduction or enter any percent (use 25% for quarter size). Also, I use the slowest resize filter for best results; there are several in a panel on the Resize dialog.

However, I like a little better final results with no halftone remaining, so I blur twice more. Once at this size and once at an intermediate size.

This image results from repeating the Blur step.

This 120x120 clip shows that some remnant of halftone patterning remains. This is better removed by resizing and blurring again.

Some day I'll take the time to run a few pix through this process, then do it again skipping this blur step, to see how it impacts the final image.

A test image that I took using the scanner's Descreen option looked rather good at the outset (the scanner delivered a 300 dpi image). I blurred it once, reduced by half for 150 dpi, and it looked as good as a result from this process. However, to Descreen, the scanner scans in a peculiar version of 1200 dpi, capturing each color separately, so it takes much longer than an "ordinary" 600 dpi scan. I guess I prefer to be "doing something" for the same amount of time, such as fiddling with IrfanView! So, I do more steps.

Though this image is displayed the same size as the ones above, it is half the size "behind the scenes." Click on it and see. The resize averaging makes this look a little better than the prior image already, at this size.

This 60x60 clip covers the same area on the photo as the 120x120 clips above. The halftone patterning is less evident yet, just from the Resize operation.

This is the clip above, resized to 120x120 without smoothing, to show the pixels. Compare it to the clip for the prior photo, the result of two Blur operations. I have to look closely to see remnants of the halftoning.

I encourage you to experiment. I had a little theory to drive me; I knew in a general way what the Blur operation does, for example. It may be that starting with a 300 dpi scan and using fewer Blur steps, perhaps at a % different from 99, will work as well. I am usually in production mode, so I must consciously block out time to experiment or I don't do any.

This is the result of the last Blur operation, done on the half-size image.

A 60x60 clip shows things are a lot smoother, but some irregularities in the girl's complexion seem to have vanished. She may prefer for us to hide signs of acne or moles, but let's wait for the final result.

This is again the small clip resized to 120x120 to show the pixels.

I can see no hint of halftone patterns, not even the Moiré patterning. However, the edges are no longer as sharp as before.

We will be shrinking this image further, to get it to final dimensions and resolution. Remember, our goal is to display at 150 dpi, and this is still at 300 dpi.

This one ought to display at a smaller size than the ones above. This is now ¼ the size of the initial scan.

A 30x30 clip shows we have a pretty sharp image now, for this resolution, with no sign of the original halftone.

This 120x120 blowup of the tiny clip above shows the pixels. You can see that the edges are just two pixels across.

Many times, you can stop right here. At the risk of resurrecting some sign of the screens, I like to do a final sharpening step. Most of the time, I like the result better.

In the Effects Browser you can set the amount of Sharpening to do. I usually set it at 20%. Irfanview does a full sharpening (100%), which you can try to see how blocky it looks. But when you add 20% of that to 80% of the original image, it looks pretty good. This is my final, production image. Overall, there is a somewhat grainy look that makes this more like a photo than a halftone print.

The 30x30 clip is now displayed at the same resolution as the larger image. The total image has plenty of snap and interest. And let's remember that this started as a stamp-sized snip from a 3½x5 inch image.

This blowup of the 30x30 to 120x120 shows that the apparent width of edges is closer to a single pixel, as would be the case if we'd scanned at 150 dpi an original photo that had hundreds of dpi. Because of the halftone image we started with, 150 dpi is actually better than is warranted, but it gives a good combination of "look" and size.

There you have it. Start at 600 dpi, then Blur, Blur, reduce by half, Blur, reduce by half again (to ¼ size), Sharpen, and you're done. It really doesn't take long!

Thursday, February 21, 2008

Eclipse 2008 - the last for a while

kw: observations, astronomy, photography

Last evening I got out (in 5-minute spurts—it was well below freezing) with my camera to observe the last Lunar eclipse that will be visible in Eastern North America before 2010. The images in this montage are clipped from much larger frames; they are 300x300 clips from 6Mpx images. Image times are 9:02, 9:14, 9:24, 9:34, 9:46, 9:54, 10:04 and 10:19pm Eastern.

I've had my camera, a Nikon D40, about a year, and I really love it. However, it is not well-suited to astronomy. Two deficiencies bugged me: the lack of a cable release shutter (and too hard to work self-timer in the dark), and focusing troubles. As to the latter, I managed to get it into a mode so that it could autofocus on the moon, until it got too dim (the sixth image), after which I had to switch the lens to Manual focus and eyeball it. The lack of any of the focusing aids found in film SLRs made this very iffy. I basically took several pix at a time, refocusing each time, hoping to hit the sweet spot once each set. I did OK. Once shutter times got slower, however, camera shake became an added complication. At least I have a sturdy tripod.

It just occurred to me that I could have taken some of the earlier images, at least, by setting the camera to continuous shooting (2.5 per second), and held the shutter down while I slowly focused through infinity and beyond (only in a camera can you go beyond infinity!). I haven't tried continuous shooting with shutter speeds of a second or so!

This image was processed a bit to give the Moon an appearance closer to what I could see visually: lower contrast and more yellow/tan than orange/red. The tiny dot at the top is the star Regulus, which was 2° North of the Moon at the time. Saturn was also nearby, about 5° East, but my image frame wasn't wide enough to put the Moon on the autofocus spot and see Saturn also.

The ability to capture Regulus (Mag 1.4) in a 1/10-sec exposure at f/5.6 and ASA1600 gives me some idea what I'd need to do to get wide-angle sky images with this camera. First, I need a desert or dry mountaintop location, so stars of sixth magnitude are clear to my eyes. Then I need to mount my camera on a tripod with a clock drive, because each magnitude requires a 2.5x longer exposure.

To get a 1.0-magnitude star captured this well takes 1/15 sec; at f/4 (my wider-angle lenses), 1/30 will do. Then 6.0-mag stars would require 100x the exposure or 6.7 seconds. However, with proper setup, my telescope tripod will keep a camera pointed at the right part of the sky for a minute or more. A 60-sec exposure would then image 8.4-mag stars with similar intensity as that seen here, and probably show some a magnitude or so fainter. Of course, "visible" stars would be very overexposed, but that's typical of astrophotography.

The curvature of the Earth's shadow in the upper images gives one a feeling for the size of the Umbra, even 240,000 miles (385,000 km) away. The Umbra actually reaches, on average, 855,000 miles (1.38 million km) beyond Earth, and its diameter at the Moon's distance is still 5,700 miles (9,200 km), or about 2.4 times the diameter of the Moon. Though the Moon was off-center to the Umbra (as usual), and because it travels its diameter in just under an hour (orbital speed 2,100 mph or 3,350 kph), it was fully engulfed in the Umbra for just under an hour. According to the Sky and Telescope site, the central phase—totality—lasted from 10:00-10:52pm EST (UTC-5h).

Some folks wonder why the Moon turns orange. If you were on the Moon at the time, the Earth would appear dark except for a bright red rim where light scatters through the atmosphere. During the rare eclipse in which the Moon passes through the center of the Umbra, it gets much darker, as you can see to the left side of the later images. When the Earth has more cloud cover than usual, and the Moon hits the Umbra dead-on, it seems to vanish from the sky...slowly, like the Cheshire Cat's smile.

Monday, February 18, 2008

Archimedes - more modern than we knew

kw: book reviews, nonfiction, ancient history, manuscripts, history of science

It may hold the record for the most money paid at auction for the ugliest book (US$2.2 million). It was a wreck. Its sale has caused endless speculation—mainly about who bought it—and endless joy among historians of science, plus endless fascination by quite a variety of scientists who had previously had little truck with "old books."

Word of the day: palimpsest. Noun. "A manuscript that has been written on more than once; the earlier writing is often incompletely erased and partially legible." See FreeDictionary for more details) Origin: Greek palin (παλιν) "again" + psēn (πσην) "scrape". Why "again"? Parchment is animal skin, soaked and scraped to remove hair and fat. So to "erase" older writing, a sheet could be soaked and scraped again.

This helps understand the importance of a 13th Century prayer book comprised of sheets from a number of older works, including 10th Century manuscript copies of three documents written by Archimedes more than a millennium earlier.

This "ugly book", shown here during its display at Chicago's Field Museum, is a rare find indeed. It is the only surviving codex (bound book, as contrasted with a wound scroll) of Archimedes' work. All images in this post are Copyright the owner of the Archimedes Palimpsest, used by permission.

The Archimedes Palimpsest, AKA Archimedes Codex C, contains most or all (not yet sure) of the text of Floating Bodies, Method and Stomachion, works previously very little known from incomplete quotes. Why "C"? Two other codexes, "A" and "B", existed in "slightly modern" times, but vanished a century or two ago. We don't have them in Greek any more, but in translations...all partial, ranging from good to "interpreted" (i.e. paraphrased).

Late in 1998, when Codex C was auctioned, a museum curator somewhat hopefully contacted a well-known dealer in manuscripts with the suggestion that the Walters Art Museum might be a suitable venue for public exhibit and scholarly study. "The Walters" in Baltimore, Maryland houses and cares for a large collection of manuscripts. Imagine his surprise to find out the buyer already knew of the Walters and considered it the best such venue!

After a relatively short time (compared to the document's age) the dealer and the owner of the codex visited Will Noel to discuss its curation. This was a formality: the owner had it in a bag he was carrying, and that was that! Dr. Noel and a colleague, historian Reviel Netz of Stanford, became the lead investigators. After nearly ten amazing (and arduous) years of work, they have written The Archimedes Codex: How a Medieval Prayer Book is Revealing the True Genius of Antiquity's Greatest Scientist. The work has gone amazingly fast, primarily because the owner, is a "rich patron" who makes quick decisions and is very interested in the findings.

What is it like to deal with a palimpsest? Codex C has 174 "leaves", or parchment sheets, folded in the middle and bound together. This produces 348 "pages" with 696 "sides". This photo, taken in deep blue plus near-ultraviolet, shows the state of the art for a hundred years or so, since it became feasible to produce UV light. The sheet is oriented so the Archimedes text is readable, if you read Byzantine Greek. Two diagrams are also visible. The text was written in two columns.

The way UV makes both texts visible is by fluorescence. If you have a "black light" tube, shine it on your skin in a darkened room. That dim bluish look is flourescence (your teeth are much brighter-look in a mirror, but not for too long: UV is bad for your eyes). Ink is not fluorescent, whether it is iron-based or carbon-based. So the bluish light from the parchment is blocked by the older ink almost as much as the newer, because some of it had soaked into the parchment and absorbs light from beneath. To take such an image, the camera has a filter that blocks the UV but passes the fluorescent colors. The full-size version of this image can be found at the Archimedes Palimpsest web site.

The overlay of late Byzantine Greek prayers runs vertically, which is typical of a palimpsest: cut a re-scraped sheet in half (where it was bound) and rotate it, so you can write over it with less distraction from the remaining under-text. This text is in one wider column per "side". This is sides "017r-016v", or the reverse of half-sheet 17 and obverse of 16. Adding the other side, the sheet's contents are 15r-16v-17r-18v; "r" and "v" mean recto and verso, or front and back in Latin.

"Well," you might say, "It looks straightforward. Take the sheets out of the 'book' and photograph them in UV light. Then read it right off." But you knew, didn't you, that it isn't that simple? Firstly, taking out the sheets, or disbinding, was a horrific task; the book had been rebound a number of times, most recently with something like the "white glue" named after a famous cartoon bull. Modern polymer-based glues are hard to dissolve without also dissolving parchment!

Enter Abigail Quandt. Her work is the key to all later successes. Disbinding Codex C took her four years. That is around eight days per sheet (the profession's word for sheet is "folio", the term you'll find in the book).

Once she had "released" a sheet from its binding, Drs. Noel, Netz, and an ever-growing team could begin their work on it. This corner of a page shows a rather good section that is almost readable without doing a letter-by-letter puzzling out of the least for someone who is familiar with 10th Century Greek manuscripts already! This image is a little more sophisticated than the prior one: digital images of UV and visible were subtracted to enhance a text that was all but invisible in UV light alone. But what to do with even-less visible text, and the few sheets with rather recently-forged iconography painted and gold-leafed over both older texts?!?

This image and that which follows are two similar methods of multi-spectral imaging. Several imaging teams have worked with the authors over the years, and on one occasion a competition was held between two teams. Both worked out schemes that emphasized the very slight color difference between the 10th Century iron-based ink (seen as red) and the later carbon-based ink (seen as blue-black).

My brother, one of whose skills is "scribe", described for me how medieval ink was made using red iron oxide, oak gall bitters, and carbon black. Later inks using linseed or other oils and carbon black were used because they are easier to make, and rooms full of monks busily writing at "publishing" monasteries needed an abundant supply...carbon black is easily made and needs no grinding.

These lovely images show the same portion of a sheet, with essentially no difference in legibility, but before the computer got hold of the various narrow-band images, the sheet looked blank under any "eyeball" presentation at any least there was no visible under-text. To these folks, the 13th Century text is part of "blank".

Over time, the extension of such techniques has yielded readable, or at least decipherable, text for all but the four sheets overlaid with forged images (it is supposed that someone in the 1920s or '30s tried to make the ugly book prettier for a quick, and more lucrative, sale).

X-ray fluorescence provided the answer. A proof-of-concept yielded an "iron image" right through the gold fifteen hours for about a square inch. Work currently under weigh, or perhaps recently finished —it was just beginning as the book was printed—, uses the much brighter X-rays produced by an atom-smasher, and is much, much faster.

I've worked with folks on a project using such X-rays. You have to be careful with the beam. They typically keep a sheet of paper in front of the beam port. When it bursts into flame, the beam is "on". So you block the port, put the filters in place for your current experiment (usually, chunks of aluminum!), and open the port to make your readings. Of course, the blocking and unblocking of ports is done from outside the room!!!

What discoveries did all this lead to? Besides the texts themselves, they revealed an Archimedes who was much more modern in his thinking than we imagined. And his work was not the only material bound into the codex, but I'll leave off discussing the other documents with which his three texts have kept company for a millenium.

Firstly, Method reveals how Archimedes determined the area or volume of certain curved shapes. In at least one instance, rather than sneak up on the infinite quantities that can arise in such calculations, he used them directly. If you write your equation appropriately, you can divide two infinities and get a non-infinite result. This is the basis of all calculus, meaning all of modern engineering and much of physics. Before Codex C, it was not known that Archimedes was able to calculate using infinite quantities.

Secondly, On Floating Bodies reveals an Archimedes quite different from the legendary buffoon that ran naked through the streets shouting "Eureka!". He already understood the principle of displacement, and in this work he showed how to quantify the density of a floating, or sunken, body. I recently used his method to measure the density of a chunk of rock I've carried around since finding it in a barren field in Oklahoma. Its density is 3.6, which is dead-on for a stony meteorite, but too heavy to be a misplaced piece of basalt (3.0-3.2). Now I gotta get an expert to look at it...

Thirdly, Stomachion, the "belly-ache", is a playful puzzle, a square cut into fourteen triangles. It is rather hard to re-assemble after you mix up the pieces, yet there are 17,152 ways to put it together (and millions of ways to be wrong). Archimedes proposes determining how many ways there are, and the researchers found he had the mathematical tools to arrive at the correct answer, without need for a computer.

The story of this ugly book is not over. It has yielded conceptual beauty of several kinds, with much more to come. These people have job security!

Friday, February 15, 2008

One fish, two fish...

kw: musings, business, searching

For your translation needs, there's BabelFish*.

For everything else, there's the GoogleFish!

*BabelFish is a product of altavista™.

This editorial cartoon by Daryl Cagle showed up in the morning paper today, and I ran right down and scanned it. This is a de-halftoned, small version of the scan. You can also see an original color image (as long as the link lasts).

I think Mr. Cagle has captured the essence of just how important searching is. During the past decade, I've moved professionally from info tech to info science. Whatever IS was called in the distant past, it has been around since Mesopotamian herders began to use marks on clay take inventory ("Where'd I leave the tablet with Sam's receipt?"). We originated as hunters and gatherers: searchers. It is still what we do best and most obsessively. Ya gotta search to get work, food you can afford, a mate, a dwelling, transportation, and on and on...

Searching is big business. I work for an industrial company that does a lot of research. The library services division does mainly two things: catalog things so it will be easy to find them, and find things, particularly things that aren't well cataloged. Most of such "things" are books and smaller documents. I am now the main custodian of a thesaurus...not the book by Roget, but a large collection of keywords and key phrases ("terms" in the profession), arranged in a hierarchy, also called a "controlled vocabulary". The cataloging tasks aim to attach appropriate key terms to things like tech reports, so someone can later find documents that are useful to them. In this context, the cataloging is called "conceptual analysis," and employs a number of rather costly experts who can quickly read a document and extract concepts that they render as key terms from the thesaurus, anywhere from five to a couple dozen per document.

This kind of cataloging is quite a bit different from putting a Dewey Decimal number on a library book. Each book gets one key, and one only. The numbers keep the keys short. For example, DD numbers in the 800s are "Literature". 8n1 (n = a digit 1-8) means "Poetry", where 811 is "American poetry in English", 861 is "Spanish poetry" and so forth. Digits after a decimal further refine the subject. But in the poetry section, I have seldom seen digits after the 811 or 821 ("British poetry"); poets seldom stick to a narrow subject beyond a single poem. You'll see strings of three or four digits (after the decimal) for narrowly focused books. Longer strings are for multiple, discernible foci; but this is rare. If you see a humongous DD number, ask your librarian to explain it.

Of course, the people that search my company's document collection don't only use key term searches. They can also search for documents that contain any word(s) they like. Now that everything is automated and on disk, searching is getting simpler all the time. However, "free text" searches tend to return a lot of clutter. Thus, large companies find professional cataloging and indexing worth the cost.

What about the rest of us? We have Google. Google is so big in searching now, we use the new verb "to google" even when we are searching via altavista or Yahoo! or DogPile. By the way, for the opening page that Yahoo! used to display, they employed professional indexers to categorize the first set of links you'd get when you clicked on a category. That has become rather unwieldy, with millions of new web pages daily, and I don't think they do it any more. What does Google do, to retrieve pages we find useful? Two things.

Firstly, the thing they get all the press for: the "popularity ranking" method. When they track down web pages, they keep track of how many other pages link TO each page. A web page with lots of links to it gets a higher score than one with a few or only one. Of course, many pages (possibly most) have no inbound links at all. When you get a small number of hits, the screwy ones in the last half of the list are likely these poor orphans.

But secondly, they set up a smarter sorting method for searches against more than one word. Search for peach and only the first method can be used. Peach fruit, peach trees, and Peachtree software are ranked only by popularity (I just got 58 million hits on this word). Enter peach tree, and you'll get a much smaller number (297,000 just now). Now try tree peach (889,000). What happened?

In the past, with anyone but Google, peach tree and tree peach would get the same number of hits, perhaps not in the same order, and a much larger number than for peach alone. That's because you'd get every document that contained either peach or tree, in addition to the ones you wanted that contained both words, and if possible, the phrase peach tree. The Google method assumes you want every "significant" word in your search phrase to be in all your hits. The "significant" words are words besides "and", "the", "you", "that" and so forth; you can search for "dogs that are larger than forty pounds", and the search will really be done for "dogs+larger+forty+pounds".

Finally, the multiple words have a certain order, and phrases are given priority. If a lot of phrases show up, Google won't give you documents without the phrase. Otherwise, it gives you all the documents that contain all the significant words in any order.

Why go to so much trouble? People really care about what they find. Enough to buy lots of stuff based on their searches. Retailers and service companies pay Google a lot for help getting their web sites found more easily, and for priority placement (pay Google, and you go right to the top!).

That simple business model has made Google too big for Microsoft to eat whole, so it tried to eat Yahoo! far Yahoo! has slipped from their grasp. We'll see.

Thursday, February 14, 2008

About as white as a black man can be

kw: opinion, politics, elections

Churchill said, "Even a fool is right once in a while". I don't like almost anything Bill Clinton has to say, but when he said the other day that he'd waited his whole life to vote for a woman for President, and for an African-American for President, it echoed my own feelings. His next words, that he'd be voting for the woman this time, reflect a sentiment opposite to mine. I'd love to vote for a female candidate, but absolutely not this woman. Senator Clinton is the wrong woman for the job.

I wouldn't take much for Senator Obama to move to the right of Senator McCain. Were he to do so, he'd have my vote. Not because he's black (what, 25%, 15%? I am almost that black!), but because he's the most creative candidate on the stump, by far. Trouble is, he doesn't have a moderate bone in his body, so far as I can tell. Maybe after the Nomination we'll find out better, when he has to oppose not a Clinton but a McCain or a Huckabee (yes, he still could pull it off).

I am a Republican by registration; sadly, I find it necessary to also state that I am a conservative by inclination. Such a statement is no longer redundant. Further, considering the original meaning of the word, I am also a liberal, just the way Lincoln, Jefferson, and Washington were liberals: they were in favor of people being free, being liberated. Real liberalism helps people better themselves but doesn't replace them. Such liberalism is perfectly in accord with historical conservatism: keep the good stuff and mind your own business.

The modern use of the term "Liberal" (capital L is typically clearly pronounced, particularly by "conservative" commentators), is just the opposite. We don't have a term for the monstrosity that is modern limousine liberalism: the protect-everyone-from-everything-at-all-costs(especially to the taxpayer), we'll-do-your-thinking-for-you, you-deserve-total-care, be-nice-to-everyone(esp. terrorists)-and-they'll-be-nice-to-you, cradle-to-the-grave attitude that I'll dub "Nannyism".

At least a decade ago I read Alan Stuart Blinder's wise Hard Heads Soft Hearts: Tough Minded Economics (click here for more). "Hard heads" refers to conservatism, "soft hearts" to liberalism, as we understood them at the time. He showed that Congressional politics typically produces "solutions" that are hard hearted and soft headed. Just for one example, "welfare" programs have a noble ideal, but their actual implementation destroys persons and families and actually makes it very much harder for a person to return to "taxpayer" status than if nothing whatever were done! The present exceedingly miserable state of most African national cultures is a result of misguided nobility on the part of 19th Century missionaries. Look to 1980s Africa to discern the future of Nannyism.

Oddly enough, many members of both major parties are Nannyist, in different ways. Left-wing Nannyism we call Socialism, and right-wing Nannyism becomes Fascism. Both destroy everything that holds a healthy society together.

As a solution, I propose MYOBism, where MYOB means "Mind Your Own Business". We need a strong stance internationally to ensure we have the chance to mind OUR business appropriately, so I lean to the right when facing outward. We need clear-eyed policies to help those who need it most without preventing them from rising above that needy level, and without penalizing those who are in a position to support such programs. The Laffer Curve, much loved by Ronald Reagan, has been shown to work. The "Clinton economy" was really a result of Reagan's and Gingrich's policies at work, in spite of Clinton's best efforts to derail them. Ironically, these policies, derided by Democrats at the time, were also held at arms' length by Republicans, who found them too "liberal". They were! They are! Reducing onerous tax burdens is a historically Liberal stand. I lean to the left domestically.

But I am anti-Nannyist. Today's Nannyists would kill the goose that's laying golden eggs, even though that poor goose is struggling right now. Both Senators Clinton and Obama are sharpening their carving knives.

Who isn't? Senator McCain isn't totally in favor of a living goose, but he's quite a bit more likely to let it live, and for that reason, I'll vote for him. Uncertain survival is better than certain demise.

Monday, February 11, 2008

Squeamish? Skip this one

kw: book reviews, nonfiction, forensic anthropology

Having been honed for survival over the eons, a body is hard to get rid of. I understand that, even after incineration at 1800°F (1000°C), AKA cremation, the "cremains" are a recognizable skeleton, though it is a bit fragile at that point. This is ground to a crumbly powder before being "inurned" and turned over to the heirs or ensconced in a mausoleum.

The bones of dinosaurs and other fossil creatures have been petrified, or filled with minerals and thus turned to stone (though oftentimes the original bone is still there, intercalated with the stone). Not all fossil bone is petrified. I've handled non-petrified bones from the Badlands of South Dakota and Nebraska. After 13 Million years, they're a bit crumbly, but still hang together rather well.

Thus, it is a bit ironic that so many killers try to dispose of "evidence" with fire, by torching a car or house containing the victim(s). Bill Bass and other forensic anthropologists are in the business of proving that the most dedicated body-destroying murderer (or natural disaster) will still leave behind enough bits to determine the sex of the remains, the approximate age and stature, and usually the time/date of death and the person's race.

A side point: "race" is a much-disfavored term these days, but it happens that, by measuring your bones, and comparing the results to a database of such measurements, an anthropologist can indeed determine whether you are predominantly of European, African, Asian (including "Native American"), or Austronesian ancestry. In particular, although "black Africans" (which are not all as black as you might imagine) include dozens of ethnicities whose anatomical characteristics differ from one another more than most of them differ from European, all differ significantly from the range of European characteristics and can be clearly distinguished from them. American blacks who are descended from slaves range from near-European to near-African in type, being nearly all of mixed ancestry.

Some disasters, though human-made, are nearly on the level of "acts of God" such as tornadoes, in destructiveness. In Beyond the Body Farm: A Legendary Bone Detective Explores, Murders, Mysteries, and the Revolution in Forensic Science, Dr. Bill Bass and Jon Jefferson record one such, an explosion in an illegal fireworks factory in Tennessee blew eleven people to bits. A twelfth lucky fellow was "only" blown over the house into the front yard, landing on soft ground with some injuries and fractures but alive and with no parts missing. Those nearest the blast were found in several locations each. One flying body snagged on a branch and left a trail of entrails...OK, that's enough!

The point here is, with both flesh and bone to work with, Dr. Bass and his helpers were able to put everyone back together like 11 jigsaw puzzles, and get everyone identified (even one guy whose face was never found) so the right family buried the right body.

More frequently, an investigator has only the bones to work with, and often enough, not very many of those. These days, the DNA in the pulp of a single tooth (even after a fire) is enough to ID someone, though few watchers of CSI realize that DNA analysis can take weeks or months. For most of Dr. Bass's career, he has had to use dental records and old X-ray records to confirm an identification, and DNA has not always been the solution to even modern cases.

He is most frequently called on to determine approximate time of death. Since setting up the Body Farm he has become the foremost expert on modes and timing of the decay of human corpses. From his web site:
On the campus of the University of Tennessee lies a patch of ground unlike any in the world. The "Body Farm" is a place where human corpses are left to the elements, and every manner of decay is fully explored—for the sake of science and the cause of justice.
The rate at which a body loses its flesh, the timing and order of insect attack, and how all these depend on average temperature, are now well known. Only at temperatures substantially below freezing will a corpse's decay be halted, even for an "embalmed" body (the degree of embalming is quite variable, it turns out).

As "Jefferson Bass", Bass and Jefferson have written a series of mystery/detective novels based on cases involving Body Farm expertise. However, thirteen the actual cases detailed in Beyond's sixteen chapters make reading that I find more fascinating than any fictional treatment. The most touching is the exhumation and X-ray analysis of the body of "Big Bopper" (J.P. Richardson, Jr.), a process that brought comfort and closure to his son and grandchildren. The son was moving the body to another location, and asked Dr. Bass to take advantage of the opportunity to either confirm or put to rest rumors of conspiracy and murder. The analysis showed that Big Bopper, along with Buddy Holly and Ritchie Valens, died of incredible injuries suffered during the crash of a small airplane in 1959. Rumors of gunfire and death after the crash skittered about for years, even decades. The first glances at X-rays of Richardson's legs made it clear he could not have walked away from the crash.

The book is not for the faint of heart. I was hesitant to read it, but found I am not so fainthearted as I least when it is someone else's demise and decay I am reading about (At age sixty, I still cannot watch myself being injected or getting an IV put in. Seeing the inch or so of blood that goes up an IV tube before they push it back in with saline solution can make me faint).

The skills of Dr. Bass and his colleagues—who now number in the dozens if not a hundred or more—are phenomenal. Say somebody finds a couple of ribs and an arm or leg bone, perhaps parts of a skull. Using modern database analysis (helped by fast computers), a forensic anthropoligist can tell enough about a person that a search can be made, for example, for records of someone "asian or asian-white mix, male, thirty to forty years old, 64-68 inches tall, slender build, died July 4-8)" rather than "Middle age asian, short, died midsummer", which was state of the art before the Body Farm was set up. But as Dr. Bass states, it is fortunate that he has a poor sense of smell...

Friday, February 08, 2008

Trading partner or predator?

kw: book reviews, nonfiction, foreign trade

The top trading partners of the US are now, in order, Canada, China, Mexico, Japan, and Germany. However, on the Imports side, China just tops Canada, $296 billion to $289 billion. My first "I wonder": why do I so seldom see "Made in Canada" on something?

I found the answer to this and lots of global trade questions at the Foreign Trade page of the US Census Bureau web site. In a section with country-by-country breakdown, I found that the bulk of our imports from Canada are things and materials you won't find at Target or Big K: resources such as crude oil and natural gas, iron ore and bauxite (aluminum ore) and other metals, and then "behind the doors" stuff like industrial machinery, tractors, and building supplies including lumber. Far down the scale we find textiles, rather than finished clothing, to the tune of a mere half billion—no $10 dresses or $5 shirts—, and a billion in toys and sporting goods. Canada-produced apparel totals no more than a billion.

For China, the biggest single area is computers, computer peripherals and other electronic goods and supplies, around a tenth of the total budget...$30+ billion means lots of laptops and phones, and even more ink cartridges. The next huge area is apparel, also about $30 billion (so that's about a hundred $10 Chinese dresses for every $30 Canadian flannel shirt). Toys and sporting goods are in the $28 billion range. All these are on-the-shelf items. Chinese imports are now the visible face of American retailing. (My figures are for 2006)

Based on a more down-to-earth analysis ("Why can't I find anything in the store made somewhere besides China?"), Sara Bongiorni decided to cajole her family into a one-year boycott of Chinese goods. Her book A Year Without "Made in China": One Family's True Life Adventure in the Global Economy chronicles that year, 2005. On January 1 of that year, as the result of a week of discussions (badgering), the New Year's resolution of Sara and her husband Kevin was to purchase nothing from China.

The twelve chapters, one per month (she must keep good journals), reveal that they really didn't make it, but they came about as close as is possible. She didn't just cajole her husband (and two small, uncomprehending children) into making the resolution: She embarked on a 365-day cajoling adventure. The story is by turns hilarious, maudlin, and white-knuckle gripping.

To avoid being totally estranged from family and friends, they (Sara) opened a huge loophole: gifts (birthdays, Christmas, what-have-ya) were exempt. The loophole expanded when Sara persuaded her sister-in-law to bring certain materials (candles, etc. which are only made in China these days) for a birthday party... Her outspoken mother drove a truck right through the loophole. And when donations for Katrina-disaster relief exceeded needs, well-meaning (and giggling, I suspect) friends dropped a few boxes full of toys and other stuff on their doorstep; every item "made in China".

However, they went to great lengths to locate kids' shoes cleaper than designer ones from Italy; ink cartridges that were not only filled in the US, but filled with ink made in Canada rather than China; dolls from anywhere but China. Yep, your kid sister's Raggedy Ann and Andy dolls—and Barbie—are made in China now.

The closing scenes, after as close to a China-free Christmas as they could manage, are of a couple considering "What next?". After a year as "weakest link", Kevin proposes an attempt to continue the boycott. They compromised on shopping more thoughtfully.

This book makes you think. If we all shop more thoughtfully, there's no way we'll avoid buying lots of Chinese merchandise, but we will have a better idea of just how global our economy really is. And if you do find an ink cartridge with genuine Canadian ink, frame it.

Tuesday, February 05, 2008

Nature vs nurture in architecture and art

kw: book reviews, nonfiction, natural history

This is one of the better pictures of an orb web. Dr. James E. Carrel of U. Missouri has this image on his Biology of Spiders page there.

So tell me, how much intelligence is indicated by these webs? In Built by Animals: The natural history of animal architecture by Mike Hansell, you'll read that, while humans are the only...the ONLY mammals that build trapping structures (nets, snares, deadfalls, etc.), thousands of species of invertebrates do so. Spiderwebs, of thousands of varieties, are the major realm of animal-built traps with which we are familiar, but by no means the only one.

In addition, while an orb web may be considered a home in addition to a trap, many spiders, such as tarantulas, make silk-lined homes in burrows or other cavities. Lots of nonhuman animals make homes: bird nests, chimp and orang nests, burrows by rabbits or moles or mice...and even fish!

This illustration from the Project Gutenberg Ebook A Book of Natural History: Young Folks' Library Volume XIV, edited by David Starr Jordan, shows a female stickleback fish laying eggs in a nest built by her mate. The females of this genus of fish choose a mate based on the best nest.

I have seen, in shallow streams in springtime, what look like sunken auto tires covering large sections of the stream bed. These are also fish nests, but of a species I don't know. The males go to great trouble to clear and defend a circular area, and to heap a ring of debris around it, to attract females. Each ring is about 2/3 of a meter across or more, the size of a tire. How much smarts is needed by these fishes?

Dr. Hansell, author of several book on animal architecture, surveys the breadth of structures built by nonhuman animals, from termite mounds to mole rat burrows to the more familiar nests and webs. Many, many structures are found to result from repetitive actions that take advantage of material properties. Such structures fit the "good materials, small brains" hypothesis.

For example, the hexagonal cells in honeycombs aren't specifically shaped into hexagons, one by one. A group of bees will build waxen walls between one another, and when they are high enough, the bees will "shiver" together, raising the temperature until the walls soften and sort of relax into the hexagonal shape we see. Though a comb looks very uniform at first glance, a closer look reveals the kinds of small variation, including occasional 5- and 7-sided cells and small differences in diameter, that indicate their more "emergent" nature.

Stereotyped actions with specific materials indicate that such structures need little in the way of intelligent planning. While we need hundreds of planners to direct thousands of workers to build a skyscraper 350-300 times the height of a person (complete with plumbing, electricity, ventilation, and elevators), a nest of tropical termites that numbers in the millions, taking advantage of the properties of mud-plus-saliva and sometimes guided by air flow, can erect a structure 1,200-1,500 the height of a termite (if it could stand up to its full 5-6mm height).

In the last chapter of the book, the author goes 'way out on a (scientific) limb, discussing beauty. The subject is bowerbird bowers.

This male Satin Bowerbird (see Australian Natural History Safari for more information and images) is busy guarding and decorating his bower. Soon a female will arrive to inspect it. She will visit several bowers, watching from within each as the male puts on a lively performance, before choosing one to mate with.

Dr. Hansell's thesis is that the experience is, for the female, pleasurable, and she seems to be guided by aesthetic pleasure in choosing a mate. Consider if she must use a "better bower & builder checklist": (1)size of bower, (2)pretty decorations, (3)vitality of male's display, (4)versatility of male's repertory, (5)who knows what?... She has to keep track of several factors each for several bowers and performances.

On the other hand, while the male's genetics and strength go into making the bower and the display, perhaps her genetics produce a synergistic emotional response: "Not bad", or "Very nice--worth a second look", or "Oh, BABY!" This is borne out by two observations: bower building and display performing both require practice on the male's part, and younger females are more attracted to flashier decorations and displays while older ones pay more attention to factors indicating strength and endurance on the male's part. (This sounds like human females, too)

Along the way, the author discusses the problem of aesthetic sense in animals. Just how likely is it that female bowerbirds take pleasure in a "good" bower? If pleasure takes less brain power than checklist tracking, it is actually quite likely, just as we use the pleasure of taste to choose good foods (and in the absence of modern manipulations of that sense, it's a pretty good one).

Is this painting beautiful? Would you want it hanging on your wall? Would you pay for a copy? Somebody recently paid a few thousand dollars for it. It was painted by a chimpanzee under the care of Desmond Morris in the 1950s. Did the chimp think it beautiful?

There are numerous opinions about the chimpanzee's feelings, and little to go by. There is more than one way to interpret his actions. When he stopped painting, was he satisfied it was complete, or did he just get bored? Sadly, this chimp wasn't taught sign language, and is now deceased, so we won't know...assuming signing chimps can truthfully describe their feelings!

A good book like this one raises as many questions as it answers. Good questions, that a lot of future work can spring from to gain more good answers, and even better questions.

Friday, February 01, 2008

The middle-aged Earth

kw: book reviews, nonfiction, geological history, deep time, plate tectonics

OK, here is the capsule history of the Earth. The abbreviation Ma refers to "Mega-annum" or million years in the past, and Ga refers to "Giga-annum" or billion years in the past. I'll add the word "future" for future times:

  • ~4.8 Ga: Solar system formed. Earth and other planets begin to form from dust and other junk surrounding the proto-Sun.
  • ~4.5Ga: Beginning of Hadean era. Earth is molten throughout.
  • ~4.4 Ga: Radioactive-isotope age of the oldest minerals and rocks.
  • ~4 Ga: By this time, the crust has differentiated into lighter "continental" granitic rocks and denser "oceanic" basaltic rocks. This implies copious water was present.
  • 3.47 Ga: The earliest "chemical fossils", durable organic chemicals that are produced by cyanobacteria (the first photosynthesizing organisms). Coincidentally, the "rusting of Earth", the earliest Banded Iron formations, began at this time.
  • 2.3-1.9 Ga: The "rusting" event slows and stops, and Oxygen in the atmosphere rises from less than 1% to about 15%. The continents reached nearly their maximum total volume, and a combined supercontinent has formed; there may have been one or two slightly smaller ones earlier. Others would follow, because plate tectonics is now well under weigh.
  • ~1 Ga: The first "somewhat well characterized" supercontinent comes together, called Rodinia from the Russian for Motherland. This is probably between the fifth and tenth supercontinent to form since ~2.5Ga.
  • ~0.4Ga or 400 Ma: Formation of Pangea (or Pangaea), the most recent supercontinent.
  • 250 Ma: Breakup of Pangea, first in to Gondwanaland in the south and Laurasia in the north. The Permian "great extinction" may be a consequence of the breakup.
  • Today: There are seven Continents, and people on them to wonder how they came about (very few folks, admittedly, do so).
  • 250 Ga future: Formation of the next supercontinent, called variously Novopangea, Amasia, and Pangea Proxima (among others).
  • ~500 ma future: Probably, the continents will be well-scattered, as all but Eurasia are today.
  • ~1 Ga future: Another supercontinent. But things may be slowing down.
  • ~5 Ga future: It is likely that radiogenic heating in the mantle has dropped to a quarter or less of today's figure, but the solid inner core is probably still releasing plenty of heat as it grows (at the expense of the liquid outer core). If it has grown fast enough, and too little core liquid remains, Earth's magnetic field will nearly disappear, sustained only by remanent magnetism in "recent" rocks. The point is moot, however, because the Sun is about to become a Red Giant, and will reheat Earth to a near-Hadean condition. End of Earth as a life-bearing planet.
This is just the barest outline of historical Geology as I know it. This and much more is explained in fascinating detail in Supercontinent by Dr. Ted Nield, editor of the journal Geoscientist. He surveys the progress of geological knowledge, and particularly the understanding of the "Earth system" (he doesn't use the term; it's one with which I am familiar), primarily since the Enlightenment .

The understanding that Pangea was preceded by Rodinia, and that supercontinents tend to form and break up on a cycle of half a billion years, has naturally led a few scientists to project the cycle into the future. How can a future configuration of continents be projected? The primary method is to extrapolate present trends and their past rates. It is particularly important to discern what is constant (e.g. the gravitational constant), what is cyclic (e.g. seasons and orbits), and what changes steadily (e.g.Sun's increasing brightness, or decay of radioactive substances).

Plate tectonics encompasses all the theories and evidence of the Earth system. Though the term "Earth system" is most frequently used by meteoroligists, it is a geophysical term (geophysics encompasses meteorology).

Visible evidence that clearly points to plate tectonic processes is rather hard for non-Geologists to come by, but the advent of Google Maps makes it easier in at least one instance. Go there and in the search box enter Djibouti, then zoom out a few steps, and click the "Satellite" button. You'll see something like this image (click on it for a much larger view).

The city of Djibouti is near the center of the most visible Triple Junction on the planet. If you spread a few inches of moist sand on a blanket with a large balloon under it (connected to an air hose), then slowly inflate the balloon, the sand will usually crack open in a 3-armed split. Northeast and northwest of Djibouti, the Gulf of Aden and the Red Sea form two arms of such a split. The East African Rift, which passes just east of Adis Abebe (Addis Ababa on older maps) is the third.

The dark blue-to-black physiography for the ocean floors show that both seas harbor rifts down their middles. East Africa is splitting off from the rest of the continent. On your Google map, drag around to see the rift system that underlies all oceans. It is particularly striking under the Atlantic Ocean.

What is happening? At the center of a rift, magma rises from time to time, forming new oceanic crust. Follow along a plate away from a rift (you may need to cross a continent), and you'll find either a trench (e.g. off the coast of South America or Japan) or a new mountain range such as the Himalayas.

Nice thing about oceanic basalt: it contains lots of magnetic minerals. They record the orientation of Earth's magnetic field as they cool down and solidify. Nice thing about Earth's magnetic field: it reverses direction a couple times per million years.

This image from the USGS shows the stripes recorded by a magnetometer as ships crisscrossed a rift in mid-ocean. The entire ocean floor is like a huge tape recorder. It is a lot like reading tree rings to see the age of the tree, and the rate at which it grew.

Correlating the stripe pattern with fossils (which litter the ocean floor) and radiometric dates from samples gives us the timing and direction of plate motions for the past 180 Ma.

"Only 180 million years?" you might ask, "Is that all?" Yes, that is all. Older ocean floor has all been consumed by subduction into trenches, though a few small (city- or county-size) pieces have been "obducted" on top of continental crusts, forming "ophiolite belts" such as the Franciscan sequence in northern California.

Reading the ocean floor allows us to rewind continental motions back in time to the Jurassic, at 180 Ma, with some confidence. Earlier motions have to be determined from magnetic materials of known age on land, and finding such rocks that are still lying horizontally and undisturbed, is a conundrum! My major professor in graduate school has given his life to finding such rocks, and has a "second office" next to his, lined with a double layer of metallic sheeting to screen out Earth's magnetic field so he can plunk a rock into a magnetometer-goniometer and measure its tiny magnetic field.

Dr. Nield explains all the lines of evidence that let us piece together Pangea, and that give us some idea of the configuration of Rodinia and other compounded continents of the past billion years.

This illustration from a Hungarian web site sketches the timing of known and inferred supercontinents of the past. There may have been several others; we don't yet have sufficient evidence to determine. However, we do know that supercontinents form in two ways: Introversion and Extroversion.

These do not refer to personality types, at least not to a geophysicist. Introversion refers to a supercontinent's pieces slowing and stopping, then pulling back together into much the same configuration as before. Extroversion refers to the pieces continuing right around the planet until they collide on the opposite side, with the new continent's center formed by the outer edges of the earlier one. And...there's more than one way to put either type together.

From the same site as the image above, this illustration shows three competing projections of the composition of the next supercontinent. Novopangaea and Amasia (It'll amaze ya!) are alternative Extroversion models by Roy Livermore (see the Future is Wild™, which mainly speculates about the critters one might find there). Pangaea Proxima is an Introversion scenario favored by Christopher Scotese (see his Paleomap Project, which includes a nice animation of the Inversion motions).

Will there be humans, or similarly brainy creatures, living on Novopangaea (or whatever they might call it)? Further on, will plate tectonics come to an end, as it did very early on for Venus, which didn't retain enough water to keep its mantle "only" as "fluid" as stainless steel? Will the inner Earth cool enough for the process to grind to a halt before the Sun takes a whack at re-melting the planet? It is very unlikely that any of our descendants will be there to find out for sure.