Imaging tool helps astronomers study the cosmos

David Hyland

Necessity is the mother of invention.
So when University astronomers wanted to observe the overturning surface of red giant stars or other cosmic phenomenon, they invented the PowerWall to satisfy their needs.
Researchers developed the high-powered display device to visualize three-dimensional images of stars and other astronomical objects. By projecting the large amounts of information gathered by telescopes, scientists can study specific objects in detail.
With the help of emerging technologies such as the Internet 2, the invention could spark collaboration between scientists. Eventually, creators hope the PowerWall will make its way into other fields that could benefit from visualization.
“You can’t take the USS Enterprise starship and fly it out there and look inside,” said David Porter, senior research associate in the Laboratory for Computational Science and Engineering.
Porter said visualization is important for examining the astronomical data in a new way — one that allows for scientific discoveries about the inherent structures and relationships.
“It’s only with the power of visualization that you get to be surprised,” Porter said. “And that’s fundamentally how scientific progress is made. If you’re never surprised, you never learn anything.”
The actual visualization process is something similar to a cartoon. Like the single cells of a cartoon, the PowerWall plays images rapidly to create a simulated movie.
Visualized on the screen, the image of the inner structure of a red giant star is that of a turbulent sea — red and blue waves weaving and overlapping on the star’s surface.
The PowerWall was the creation of astronomy professor Paul Woodward and approximately a dozen researchers in the Laboratory for Computational Science and Engineering. As lab director, Woodward guided the project to function like an “electronic chalkboard,” allowing researchers to examine a variety of astronomical structures and interact with them.
With the project’s inception in 1985, various prototype display devices were created in coordination with private companies like Cray Research Inc.
The current design for the PowerWall measures approximately 9 feet wide and 6 feet high. With four panels or screens, more than 9 million pixels make up an image displayed on a video screen. The device can generate an image at 100 megabytes of data per second.
The ordinary computer contains only a few megabytes of power. By comparison, the computer database for the PowerWall, which processes and stores the movies created, contains millions of megabytes.
“Just as a hammer and saw extend our ability to manipulate material, computers extend our ability to manipulate data,” Porter said.
Researchers wouldn’t disclose the cost for the PowerWall because it includes staff salaries. Porter would only narrow the price range for similar devices to between $100,000 and $1 million, depending on specifications.
At the University, the lab group is specifically using the PowerWall to discover the structure and movements of fluids on stars.
While the inner two-thirds of the star is somewhat stable, the outer third — the majority of the star’s volume — is boiling. The turbulent nature of the surface is similar to water boiling in a pot with cooler water rising.
The wall’s four panels allow the scientists to examine different images simultaneously with each panel displaying aspects of the object’s structure such as temperature, density, mass or the velocity of movement.
Woodward said his group is collaborating with colleagues at other institutions to study everything from sunspots to air turbulence on Earth.
Previously, the researchers could only pass data to other colleagues by mailing tapes containing information. More and more however, the group is beginning to use the new Internet 2 connection to communicate quickly with collaborators.
“With all of these labs and collaborating places, we’re usually generating data on their major computers,” Woodward said. “(Now), we bring it across the network and turn it into images and see what the calculations really mean.”
Don Riley, University chief information officer and supervisor of the University’s Internet 2 project, credits Woodward and his group for fully utilizing the Internet 2’s capabilities in their work. Riley said Woodward’s efforts best exemplify the collaborative benefits of the high-speed network.
The lab group is collaborating with other institutions to build their own PowerWalls and the necessary support equipment. Institutions such as the National Center for Supercomputing Alliance in Illinois are in the process of constructing 16-panel PowerWalls.
The researchers said they hope the University’s proposed Digital Technology Center at Walter Library will lead to further collaboration with interested departments of the University as well as private corporations.
“We see a lot of opportunity for cross fertilization of ideas,” Porter said.
Porter said the lab’s visualization technology has an array of uses outside of astronomy. He envisions a day when the technology from the PowerWall will be used by architects to examine proposed buildings or by geologists to study seismic activity under oil fields.