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| Seeing big, bigger, biggest:
the science of supernovae |
By Juan Miguel Pedraza
Call it stargazing on steroids, high-powered astronomy, or just plain astrophysics. Whatever the name, the game is supernovae and it’s Tim Young’s favorite. |
| Young belongs, by virtue of this cosmic scientific interest, to an elite global club of experts who spend most of their time wondering — with the help of theoretical math, computer programs, and grand images of exploding stars — what in the world the world is and where it came from.
“We investigate these supernovae because they’re the most energetic objects in the universe,” said Young, a popular physics prof on campus and an eager teacher to all ages about astronomy, the stars and planets, and deep-space phenomena. “We’re looking at all of this with open minds, and we’re keen for new ideas.”
Young, whose commentary on supernova science was published last year in the prestigious international journal Nature, spends a lot of his time dreaming up new ways to model the behavior of supernovae (the Latin plural of supernova). The article summarized results from NASA’s Swift satellite observation of a gamma-ray burst transforming into a supernova. He put forth a theory that might explain observations ranging from supernovae to gamma-ray bursts.
Young writes computer programs that aim to simulate in the digital realm the truly bizarre behavior of these exploding giant stars. These large mass stars might be similar to the very first stars formed in the universe. The largest supernova ever observed occurred last year, and Young is already figuring out ways to model it.
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| Tim Young (center) supervises preparations for the launch of an educational rocket west of Grand Forks. |
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“It was about 150 times the size of the Sun in terms of mass,” he said. “Before this, I was studying supernovae from stars that were considered massive, about 20 to 25 times the size of our Sun. Fifty times was considered extreme. Now I’m going to dump a lot of energy into the model I’ve been using to get to 150 times. Can you imagine the shock wave that was sent out by that explosion?”
For Young and his cohorts who are spending entire lifetimes studying these deep-space events, the task is crystal clear, even if what they’re seeing isn’t.
“We want to understand what’s out there,” he said. “A lot of what I do is thought experiments. And I’m doing them all the time.”
He’s also working on new ways to share with students and the general public both the big questions and the new knowledge derived from his computations.
“I like to communicate and integrate concepts with students,” Young said. “That’s why I stay involved in student projects, why I do Web casting of solar eclipses (with UND computer scientist Ron Marsh) and explaining how astronomy concepts are developed (with UND’s Mark Guy in elementary science education). I want people to see what is outside of the Earth.”
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| North Dakota’s first educational rocket was designed, built, and launched this spring by a team of students, faculty, and volunteers led by UND astrophysicist Tim Young. Students also created the rocket’s portable launch pad. The launch took place west of Larimore, N.D., with the 12-foot rocket soaring on a picture-perfect flight to an altitude of 2,800 feet. The project was funded in part by the NASA-sponsored North Dakota Space Grant Consortium. It was the test bed for a much larger, higher-flying rocket scheduled for launch during the 2007 fall semester. |
| Complexity theory tests
community planning |
By Jan Orvik
Can a city fit on a hard drive? Can computer models predict whether a community is ready for change? |
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Ralph Woehle, professor of social work and an expert in complexity theory, believes they can. It’s a comprehensive way of explaining the world, he asserts.
“Computer models and complexity theory can help us explain why things happen and help us predict what may happen,” he said. Woehle believes personal relationships, interactions, and community networks can be modeled on the computer, introducing variables and watching how relationships and, with them, communities change.
His interest in complexity theory represents a convergence of his interest in math and a trend in the social sciences that employs quantitative techniques that orginated in physics and math.
Woehle thinks computers can be used to model social networks. “People have different kinds of relationships with each other,” he said. “A few people have lots of relationships, and many people have a few relationships.” And, he said, we tend to have more business-type relationships, which are weaker but connect us to almost everyone. Computer models, Woehle explained, can be used to demonstrate those relationships, and then add variables to see how those relationships — and their larger community structures — evolve.
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For example, we can model a community in which there are a lot of cooperative relationships, or a lot of dysfunctional relationships. Then we can add a stimulus, such as a life-changing event, or a change agent, to see what happens to the community.
We can put theory to the test by tracking real-life changes in a small Minnesota or North Dakota towns, or studying situations such as flooding in Grand Forks and Fargo.
For example, Woehle said, the flood and fire of 1997 that affected Grand Forks was a large stimulus that caused a large response. After the city flooded, the downtown burned, and the city evacuated, residents returned to meet the challenge of rebuilding homes and city. The severity of the experience prompted a range of aggressive measures to deal with future flood threats. The community was resilient, able to come back stronger than ever, and relationships between people improved.
Communities, like people, differ in their reactions to events. People remember for a while, then forget, learn and move on, Woehle said. But they have to be ready to change. Resilient communities are able to vary their response, disregarding the size of the precipitating event.
He’s especially interested in how communities change over time. Woehle says that as people move in and out, the degree of stability shifts. And he looks at the ways individuals can bring about change. “Changing communities is a big job,” he says. “But just one person can change a community and bring in resources.”
Woehle says that the best way to induce change in a community is to work with the most highly connected members. “You can effect more change with one person than many,” he says. Or, it’s not what you know; it’s who you know.
“Complexity theory parallels life,” Woehle said. |
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