Seeing the unseeable

The sky appeared deceptively clear one winter day in December 1992, when a DC-8 cargo plane flying over the Rocky Mountains hit a wildly bumpy patch of air. The plane lost an engine and six meters of wing before the pilot wrestled it to a safe landing.

The culprit: severe clear-air turbulence - the devastating, unstable waves that often occur in cloud-free conditions, terrifying airline passengers and crew alike.

Clear-air turbulence remains largely a mystery, but scientists at the National Center for Atmospheric Research are building computer simulation models with sophisticated computers and software to visualize the normally unseeable turbulence and, potentially, to understand more about the phenomenon.

"First we need to understand clear-air turbulence better through observations and simulation research. And maybe over time that will lead to an ability to tell where it will be and to predict it," says Don Middleton, head of visualization and enabling technologies at the National Center for Atmospheric Research in Boulder, Colo., which is conducting basic research on climate and the planet.

Dr. Middleton and his colleagues also are using computer-graphic simulations combined with real world observations to learn more about how forest fires burn, and to visualize the eye of a hurricane so that eventually it might be possible to predict where a ferocious storm will hit land, and possibly save lives or minimize property damage.

"We're trying to see what can't be seen directly," Middleton says. And seeing a problem, even through simulations, can be a huge aid in studying it. As scientists research each phenomenon over time and learn more, the added information makes the computer simulation more accurate.

Creating images of things one cannot normally see may seem an impossible task. But that's just what Middleton and about 400 other researchers and graphic artists from all over the United States demonstrated they could do at the recent "Image and Meaning Conference" at the Massachusetts Institute of Technology in Cambridge.

Their daunting efforts span broad scientific fields, from visualizing events in space to predicting weather patterns, and from seeing atoms on the surface of a metal to even seeing the boundaries between different wavelengths of light in a rainbow.

Middleton says visualization is an easier way to relay the importance of science to society, as well as to share information with other researchers. "Our visual sense is one way for us to rapidly absorb information," he says.

And one thing is becoming increasingly clear: The new imaging technologies are influencing the way science is done, and science in turn is influencing how imaging technologies are progressing, says George Whitesides, a Harvard University chemistry professor.

Keith Noll, an astronomer on the Hubble Heritage Project andat the Space Telescope Science Institute in Baltimore, Md., also sees his field being advanced by imaging technology.

"We're at the beginning of a revolution for astronomical imaging, and imaging in general," Dr. Noll says. Astronomy initially was relegated to visual observation and drawing, but the first telescope in the 1600s changed that. The next "revolution" in imaging came in the late 1800s with photography. Noll says the third revolution is at hand with digital technology.

"Digital solid-state sensors and imaging software are fueling a golden age in astronomy imaging," he says. "We no longer need to rely only on light visible to the human eye. We can take infrared pictures to see more detail. And we can correct atmospheric distortion with digital controls to see things never before seen."

Scientific images from space often aren't beautiful, but rather look like what Noll describes as one smudgy blob next to another smudgy blob. But some images have captured the human imagination, and planted the seeds for a future generation of astronomers.

Many of the Hubble space telescope's images, for example, are breathtaking, and adorn the covers of magazines and even postage stamps. The Hubble, deployed on a 20-year mission in 1990 with great hoopla, initially ran into problems when its main mirror wouldn't focus, but once it was repaired, it brought humanity closer to space, showing dramatic images of the Shoemaker-Levy comet crashing into Jupiter, and bringing back beautiful views and more details of the ring nebula.

The Hubble has another important function: It gives scientists a different angle on the universe. Before Hubble, observations of space mostly were made from one vantage point: the surface of Earth.

Noll says the space images are making humans feel more comfortable with unusual environments.

The intense solar flares and redness of Mars would have seemed foreign only a few decades ago, but now are considered commonplace pictures.

"It's important that we as humans must understand the universe we live in," Noll says. "In the past, data was held by the persons who got the images. Now, this data is there for anyone to use, and it's easier to get images out to the world now than 50 years ago."

With Hubble scheduled to end its space travels in 2010, scientists already are planning the next-generation space telescope, which is larger and can visualize the infrared wavelength. Stars glow in the infrared wavelength, so they will be more visible, even through the dust in interstellar space that obscures objects and blocks optical light.

On a microscopic level, new imaging technology, which includes amplifying and staining structures as tiny as an atom, is providing deeper insight into possible new materials for microelectronics products and components.

IBM for example, is using a special microscope called a scanning-tunneling microscope to see what a surface, such as a metal, looks like, and what the electrons are doing on that surface. Don Eigler, a research fellow at IBM's Almaden Research Center, says such images also can tell consumers, IBM management, and students more about what IBM is doing to make smaller products.

"Components that do computation are shrinking. Using the scanning-tunneling microscope, we can look at structures on an atomic level and build knowledge about their useful properties," Dr. Eigler says. IBM scientists invented that microscope, and it is the primary tool being used to study surface structure. Eigler says the technology can be used in other industries, including biotechnology and chemicals, which also need to control very small structures.

The scanning-tunneling microscope can visualize atomic structures as small as one ten-millionth the diameter of a human hair. The microscope works by bringing a metal needle close to the object that should be imaged. The tip of the needle executes a trajectory to form a chemical bond. Sophisticated computers and software turn that into an image.

The main body of the microscope fits into the palm of a hand. But it must be used with a roomful of other equipment, including a personal computer, which in turn is hooked to a larger server so the research information and images can be shared on the Internet.

Eigler says the images of the surfaces can tell scientists how electrons interact. He and his colleagues can then manipulate the electrons to get them to have desired properties to use in future computers and electronics equipment.

But the imaging technology is not just for the scientists. "It's more important now than ever before for scientists to be including the public in the excitement of discovery," Eigler says. "Images speak incredibly powerfully. They move us and excite us."

While such imaging pushes the limits of what we can see, and aims to provide deeper levels of information, scientists and artists alike question how far simulated or enhanced images should go.

Felice Frankel, an artist in residence at MIT and a photographer, said she sometimes enhances an image to better get the point across.

"As long as you tell the audience it is altered, it is OK," Ms. Frankel says.

The artistic aspects may indeed help attract the next generation of scientists. "Visualization has given us the ability to generate interest in our science," adds Middleton. During one public forum at the atmospheric center, he showed the simulated images to a standing-room-only crowd composed of people from the local community.

"Can you imagine people giving a standing ovation for science?" he asked. "People really can get inspired by the images."