For more amazing feats of 3-D scanning, check out our gallery, 3-D Scanning: How to Put the Real World Into Your Computer.
A rich history of life on earth lies out of sight—in 100 million-year-old nuggets of amber, in potato-shaped fossil eggs, and in mundane-looking ancient teeth. Correction: These things used to be out of sight. New imaging tools borrowed from medical research and industrial engineering are beginning to liberate some of evolution’s most closely held secrets. “I thought we’d never be able to see inside specimens without breaking them open,” says Harvard University anthropologist Tanya Smith. “The idea that we can go into an object like a fossil and pull a piece of time out virtually is amazing.”
The breakthrough relies on computed tomography scanning, better known as CT. It is much like the familiar process used by hospitals to image the insides of patients, but amplified to levels that would be lethal to humans. In one version of the technology, scanners create X-ray pictures similar to those taken in the emergency room in order to examine large fossils and reveal structures hidden inside. Newer synchrotron scanners can do even better, producing extremely focused beams a trillion times brighter than the ones generated by standard X-ray machines and yielding incredibly high-resolution images. There are two catches, however: This type of imaging works only for small samples, and there are a mere 50 or so synchrotron devices in the world.
While traditional medical X-rays detect only four densities in an image (corresponding to fat, water, gas, and bone), CT scans can identify hundreds of levels of density, readily distinguishing a fossil from its surrounding blanket of rock. Combining many images taken from many angles, CT scans can transform a two-dimensional picture into a precise, three-dimensional replica of the object inside the rock—enabling scientists to digitally examine rare specimens over and over without fear of damage.
The images on the following pages capture some of the most intriguing of the newly uncovered finds.
Insects in Amber
Jurassic Park taught us how insects get trapped and preserved in amber. Unfortunately, most amber is not as translucent as the examples on the silver screen. This 100 million-year-old wasp was trapped in opaque amber until it was virtually set free by researchers at the European Synchrotron Radiation Facility (ESRF)—a 1,000-foot-wide particle accelerator that creates intense beams of X-rays. When Paul Tafforeau of ESRF scanned similar chunks of dark amber from Charentes, France, he found hundreds of other insects, including fossilized beetles, ants, and flies. He and his colleagues then magnified some of the creatures and used 3-D printers to create plastic models that allow scientists to examine the creatures in detail.
Analysis of the Charentes amber has so far revealed more than 600 different insects—and not one of them matches a modern species. Tafforeau, who heads the project, began scanning dead flies for fun while he was a graduate student at the facility in 2002. “Each scan is a new discovery,” Tafforeau says, yet the ancient insects appear, overall, remarkably similar to their modern counterparts; they differ chiefly in detail. “For the most part,” Tafforeau says, “an ant living 100 million years ago looks like an ant today.”