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vineri, 6 iulie 2012

Printing dinosaurs: the mad science of new paleontology

In April of this year, I headed out to a marl pit in Clayton, New Jersey to watch a team of Drexel University students and their teacher, Professor Kenneth Lacovara, dig for fossils. Marl, a lime-rich mud, had been mined and used as the 19th century’s leading fertilizer, but since around World War II (with the development of more advanced, synthetic fertilizers), demand for it has steeply lessened, and there aren’t many marl mining businesses left in the US. The marl pits of Southern New Jersey are famous for something else, though: they have been incredibly rich in fossil finds.

In February, Dr. Lacovara had announced that the Paleontology department at Drexel would team up with the Engineering department for what would largely be a novel new project: scanning all of the fossils in the University's collection (including some previously unidentified dinosaurs of Lacovara's own finds in other parts of the world) using a 3D scanner. The Engineering department would then take those scans and use a 3D printer to create 1/10 scale models of the most important bones. But, he reported, that wouldn't be the end of it: they intended, he said, to use those scale polymer "printouts" to model and then engineer fully working limbs, complete with musculature — to create, in effect, a fully accurate robotic dinosaur leg or arm, and eventually, a complete dinosaur.

3D printing is one of those technologies which has gotten a lot of press because it has an incredibly high cool factor, but which also hasn't yet seen much practical application. Dr. Lacovara, however, was positing that this technology could be incredibly useful for solving actual problems in paleontology which have plagued scientists since dinosaur fossils were first discovered. One of the main problems with dinosaurs, of course, has been the changing perceptions of how they stood, moved, and what they looked like. These questions have been unanswered and debated largely because of scale: dinosaur fossils are gigantic, and they weigh sometimes several tons, making simple tasks like fitting different pieces together nearly impossible. At a small scale with a high degree of accuracy, however, the problems of size and weight would no longer apply. The job of modelling the physiques of these often massive creatures would no longer be left to artists working in concert with scientists, but could be worked on by the scientists themselves. Paleontology, a science which has seen massive changes in commonly held beliefs over time as more complete fossils have been discovered, could move forward now using 3D printing technology.

Let’s rewind. In 1838 at another marl pit in Haddonfield, New Jersey, the hunt for dinosaur fossils in North America began by accident, when a local resident named John Estaugh Hopkins found some interesting bones, took them home and put them on display. Twenty years later, lawyer and amateur geologist William Parker Foulke, sparked with interest in Hopkins’ discovery, headed back to the marl pit and began digging. His efforts led to the first discovery of a dinosaur skeleton composed of more than teeth in North America. It was named Hadrosaurus, known from just 35 bones, and the site on which it was found is now a National Historic Landmark.

Same bones, different day

 

The New Jersey-born Hadrosaurus is significant for more than just starting off the first wave of dinosaur-hunting fever, however. It also became, in 1868, the first dinosaur skeleton to be mounted, and then displayed, at the Academy of Natural Sciences in Philadelphia, Pennsylvania. The man responsible for that was naturalist and sculptor Benjamin Waterhouse Hawkins, who had previously created life-sized models of dinosaurs (and also some basically imaginary creatures) for the 1851 Great Exhibition in London. Hawkins based his mount of the Hadrosaurus on the work of a University of Pennsylvania paleontologist Joseph Leidy, who significantly identified Hadrosaurus as a bipedal dinosaur (previous artists had largely theorized that most dinosaurs walked on all four legs). This was certainly a step forward in our collective understanding of dinosaurs, but looking at a photo of Hawkins model, it’s still fairly inaccurate-looking to the modern eye, even if you know nothing about actual dinosaur morphology. The almost comical human-like pose, when juxtapositioned with modern artistic renderings of Hadrosaurus (or the modern mounting which was on display at the Academy in 2008) couldn’t be much farther apart. The most visible change in our understanding of the Hadrosaurus since the Hawkins mount has been that scientists no longer believe the dinosaur used its tail as support in addition to its legs, and that it probably leaned much farther forward, using its short front legs for support when necessary. That development was the painstakingly slow result of nearly 100 years of research.

My trip had actually started the day before the dig in New Jersey, at the Academy of Natural Sciences in Philadelphia, where Hadrosaurus had first been shown off in 1868. I was there to meet Ken for the first time, and to interview him about his 3D printing project, but we also spent some time looking around at the museum’s dinosaur exhibits. Hadrosaurus isn’t on display there, and hasn’t been for a long time. It was briefly brought back onto display, newly mounted, in November of 2008 to celebrate its 150th anniversary in an exhibit called "Hadrosaurus foulkii: The Dinosaur That Changed the World." This was its first appearance in the Academy since the 1930s. As I walked around the hall with Dr. Lacovara, he pointed out the few pieces of fossil which are the actual specimens. You see, much of what you look at in museums’ dinosaur halls are giant plaster casts. There are a host of reasons for this, he explained. "Sometimes the originals are in another museum. Second, display of the specimens can make further scientific study difficult." Of course, he noted, "it’s also not necessarily the best thing for the bones to be mounted." He pointed out to me one large dinosaur which had a lot of real parts, and which had clearly been mounted long ago. The thick wire frame and screws penetrated the irreplaceable specimens. Presumably, mounting techniques have come a long way since this one had gone under the knife, but all mounting presents the same challenges: to display, the parts must be put together somehow, which results in damage. Of course, he also told me, "nearly all dinosaur specimens are fragmentary" including Hadrosaurus, whose 35 actual bones are displayed in cast on a wall outlined with its actual shape, "so casts are used to fill in the blanks." When you look at it that way, it’s so piecemeal it’s not very impressive; but then, on the other hand, it is impressive, considering that the entire skeletal structure of the animal was extrapolated from so few known parts.

Dinosaur casting is a controversial subject in science. While the general public isn’t usually aware of just how "fake" much of what they’re looking at is, among scientists and museum curators, there have been arguments increasingly against the practice of casting in the name of scientific accuracy. The question, however, has historically boiled down to education. While casting a large dinosaur is expensive, there are an very few actual fossil specimens, and casts have historically raised awareness of lesser known species. Possibly the most famously cast dinosaur specimen is the diplodocus carnegii named after its benefactor Andrew Carnegie. The nearly complete fossil remains of the animal were discovered in the early 20th-century in Medicine Bow, Wyoming, and went on display at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania in 1907. Carnegie was so proud of this skeleton that he had numerous life-sized copies made for world leaders, many of which are still on display in museums — including in Paris, London, Vienna, Berlin, and St. Petersburg. The Paris replica has not been reset to conform to modern thought about how the dinosaur stood, and serves as a historical specimen, while the original specimen in Pittsburgh was fully remounted in modern pose starting in 2005. Because of Carnegie’s craze for casting, however, the Diplodocus is arguably one of the most recognizable dinosaurs in the world. Dr. Lacovara’s 3D printing project, with its decreased costs of replication, is likely to affect the ongoing debate about "real" vs. "fake" in fossils, but the positives surely outweigh the negatives in this case.

"That’s so wrong," Dr. Lacovara pointed out a giant leg cast against a wall in the dinosaur hall of the museum, "I’ve got to tell them to get rid of that." He took me behind the scenes, in the back hallway of the museum, where volunteers and students are working on huge specimens he found, dug up, and brought back from South America over the last few years. The primary find is a previously undescribed species of a giant dinosaur, which they are now in the process of cleaning, cataloguing, describing, and ultimately, naming. Possible names which are in the running were written in chalk on a blackboard. The video team, Jordan and Billy, walked in through another entrance, camera rolling, and I had to tell them, "Oh, you can’t film this." You see, these bones are embargoed — a common practice in science when findings have not yet been published. The bones don’t belong to Dr. Lacovara, or to the museum which is, as of 2011, affiliated with Drexel University. The bones belong to the government of the country in which they were discovered, on loan to Ken for a limited period of time while he develops his findings. Dr. Lacovara explained to me that most countries now claim ownership of any specimens found within their territory regardless of who finds them, which is not the case in the United States, where fossil hunting is still a largely unregulated, Wild West, you-find-it-you-own it game.

All Dr. Lacovara owns is the right to name the dinosaur, and the knowledge that if his findings are unique, he will always be the first person to have described it. "Science has always been open source," he told me, and his 3D scanning project will only increase the availability of knowledge worldwide. Beyond just printing bones to find out more about how dinosaurs walked, Ken’s believes that high quality scanning will ultimately become the standard in paleontology, a digital curation and archive of digital specimens which will serve as a "platform for global collaboration among paleontologists." Because the real specimens are priceless, heavy, and owned by various governments, museums, and even private individuals, the prospects of scanning at high quality should be fairly attractive to all parties interested in actual scientific discovery and knowledge. For Dr. Lacovara’s lab, at least, he told me that scanning all specimens is now "protocol." Other museums, including the Smithsonian, have also recently announced projects to begin scanning and sharing their collections.

Scanning fossils has further application with the use of the 3D printer, of course. Holding the 1/10 scale leg bone of a dinosaur in the palm of his hand, Lacovara explained that uses in the classroom present attractive prospects, where examination of real specimens is hardly practical. The scans can also fill in the blanks of broken or incomplete bones by replicating data from a similar part. Of course, printing all of the specimens is still fairly expensive, so for now, they’re only printing fossils from which they hope to learn some new piece of information. The process is simple: Dr. Lacovara, and his students set a bone on a table, or, if size is less of a factor, on a small rotating pedestal. The scanner used in his lab is a $3,000 NextEngine scanner, which uses simple proprietary software to scan around 1 million points on a three-dimensional object in a few minutes. It is plugged into a Windows computer. The scanning produces an STL file, commonly used in CAD. The STL file is sent to another computer, and this time, it’s the one that is attached to the Dimension Elite 3D Printer which is housed in the Engineering Department, where the actual "printing" of the bone takes place. The complete process can take just a few hours. The printer uses fused deposit modeling, a 3D imaging and printing process developed in the 1980s and commercialized in the 1990s. It takes the STL file and essentially slices it into layers, automatically generating a disposable, breakaway support structure if needed. The printing material, a polymer plastic, is laid down in those corresponding layers, eventually completing the finished object. The result is a highly faithful and exact scale model of the object as originally scanned at a given scale. While the process is still somewhat expensive, it leads to the possibility — previously unthinkable — of endless duplication, and endless faithful reproductions.

Jeffrey Kahn, a second year PhD Student in the Laboratory of Biological Systems Analysis at Drexel University where the school’s digital printer is housed said that, while he hasn’t worked directly with the dinosaur project, similar work he’s done with 3D printing for living organisms, including fish, can teach us a lot about how the animal moves. For fish, that question is complicated by water and the often mysterious mechanics of fins; for dinosaurs, it is often one complicated by scale. By engineering their way into a deeper knowledge of how the bone and joint structures fit together, science can come closer than ever before to having a more accurate picture of how the animal actually moved. "On the surface," Jeff told me, this sounds dull, because we "have an imagination and have seen ‘dinosaurs’ in CGI and animation," but, he said, if you get really deeply involved in studying the movement of them, you start to see things like "the possible ancestors and progeny" of dinosaurs. David McDevitt, an undergraduate who has worked closely with Lacovara on the project, explained that they’ll be "striving to make the animal walk as close to the way that it would have walked in the past," and the "physical model produced will be able to act as a testing platform for a whole array of different test conditions," so the application of 3D technology really could lead to a whole new level of understanding of these ancient creatures.

At the dig site in Southern New Jersey, Dr. Lacovara and about 15 of his students are digging in the sweltering, swampy heat of the marl pit, and the green dust is already covering my shoes and the bottoms of my pants. Previous finds at this site include a giant, nearly complete fossilized turtle shell which was around 65 million years old. Ken shows me an iPhone application called Theodolite which he uses for surveying the land at the dig, bringing another layer of technology to work that hasn’t largely changed in around 100 years. When I inevitably asked him if he could ever foresee a Jurassic Park situation, he laughed at me, and said, "the chances of that are 1 in a million, but it’s likely that we’ll find some DNA which will lead to further discoveries about what dinosaurs were like, genetically." The field is changing, he tells me, and paleontologists’ work is diversifying and specializing, but it’s also becoming more interdisciplinary. The work his department is doing with the Engineering department is really only the beginning, and he told me that he can envision a time when more and more paleontologists rarely — if ever — dig in the field. Many, he says, will eventually work only in labs and archives, as access to digitized data becomes more ubiquitous. Dr. Lacovara, however, seems to relish his time in the field, and speaks fondly of surviving for sometimes months at a time in tents with limited food and no internet while digging, searching, for as-yet unnamed massive dinosaurs. He sees his field, previously limited with regards to funding, geography, and access to specimens — moving toward collaboration and technological advances which will lessen the need for people to head off to remote places looking for a special, one in a million find. "But," he says, smiling enthusiastically, "you’ll always need people to find the bones."

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