Mother Nature keeps moving the goalposts for Anthony Mezzacappa and he wouldn’t have it any other way. His years of dedication to computational and theoretical astrophysics research, even as the landscape shifts, have earned him election as a Fellow of the American Association for the Advancement of Science (AAAS).

The AAAS Council bestows this honor on members whose “efforts on behalf of the advancement of science, or its applications, are scientifically or socially distinguished.”

Mezzacappa is the Newton W. and Wilma C. Thomas Chair in Theoretical and Computational Astrophysics and a College of Arts and Sciences Excellence Professor. He develops sophisticated models of supernovae through roles in UT’s Physics Department (since 1994) and at Oak Ridge National Laboratory (since 1996). It’s the foundation for his AAAS Fellowship, where he was cited “for distinguished contributions to the field of computational and theoretical astrophysics, particularly for developing theoretical frameworks and computational methods to model core collapse supernovae.”

“The AAAS Fellowship is about the advancement of science writ large,” Mezzacappa said. “This Fellowship really is special in that sense. I’ve spent a lot of time doing things for the field and for computational science. It’s really nice to receive a recognition of that.”

From Upstart to Leadership

Early in his career Mezzacappa was the principal investigator for the first large-scale, multi-investigator, multi-institutional computational astrophysics effort in the country to focus on core collapse supernovae. That was the beginning of a long list of professional accomplishments in astrophysics.

“When you first start out, there are more senior people who are leaders in the field and you’re a young upstart,” he said. “I was glad to get the vote of confidence by senior people to lead that effort.”

He said he knew after directing a program of that size there was no going back to smaller initiatives where he’d be the lone PI on a single project. He also noticed that over time, he and his contemporaries evolved from upstarts just beginning in the field to leaders who were guiding it.

“That changes the whole responsibility,” Mezzacappa said. “It changes how you think about yourself and your field. One of your jobs is to usher the science forward, which implicitly means with integrity and scientific accuracy.”

For him, it also means cultivating a network of fellow scientists to dive into the mysteries of astrophysics.

“Over time, you wind up contributing where you can, where your strengths are,” he said. “One of the things I know how to do is build and manage projects and programs. I created the largest core collapse supernova theory group in the world here between (ORNL) and the university.”

That gift for organizing expertise and assets has certainly benefited the research and teaching environment at UT.

“Professor Mezzacappa is the definition of a fearless scientist who chases after the solutions to some of the most challenging and interesting problems underlying how the universe functions,” said Adrian Del Maestro, professor of physics and head of the department­. “The recognition by the AAAS for his dedication to discovery in computational astrophysics is well deserved, and the department (and especially his students and postdocs) are extremely lucky to have Professor Mezzacappa at the University of Tennessee.” 

Moving the Goalposts

When a gigantic star can no longer support its own weight, gravity will eventually cause it to collapse on itself in some of the Universe’s most spectacular fireworks. When Mezzacappa and his colleagues were first developing models for core-collapse supernovae, they began with spherical symmetry, though they knew the physics would eventually lead them to more complex models.

“We always knew that we had a long way to go,” he said.

As they accumulate a deeper knowledge base and their tools (supercomputers) get bigger and faster, Mezzacappa said astrophysicists can now create beautiful three-dimensional supernovae models. As amazing as they are, however, those models still don’t answer all their questions.

“The thing that’s really changed is that Mother Nature is moving the goalposts,” he said.

“When you start out you think it’s a fixed target, because you have limited knowledge,” he went on to explain. “As you learn more and move forward, you realize the problem is even harder than you imagined to begin with. As the models have gotten more sophisticated, we’ve discovered the physics of supernovae is richer, and some of that richness is very challenging to model.”

To Mezzacappa, that’s part of the what makes fundamental science so meaningful.

“As humans, we always want to find the answers,” he explained. “As I’ve grown, one of the things that’s changed is that I kind of enjoy the mystery more now. I think knowing everything would be quite boring.”

Back to the Beginning, and the Future

Mezzacappa was in high school when he first learned about Einstein’s theories and decided what he wanted to study for the rest of his life.

“Relativity is what pulled me into physics from the get-go,” he said.

Decades later, his work keeps him close to the spark that ignited his imagination. He explained that core-collapse supernovae are one of the primary sources of gravitational waves and the only known source from which they’ve yet to be detected.

“We are in a position now, because we are a leading group and we have some of the leading models, to make predictions for what the gravitational waves for the supernovae look like,” he said. “I feel like I’m really contributing—not just to astrophysics but to relativity, which is special for me.”

The Most Important Impact

The AAAS Fellowship is one of many honors Mezzacappa has earned over a distinguished career. In the past year he’s been named a College of Arts and Science Excellence Professor, won the College’s Senior Award for Excellence in Research & Creative Achievement, and been recognized with the university’s Alexander Prize. He was elected a Fellow of the American Physical Society in 2004 and a UT-Battelle Corporate Fellow in 2005 in recognition of his supernova research and his broader role in the development of computational science in the United States.

“They all mean a lot,” Mezzacappa said of his honors, but “your most important impact is the impact you have for others, not for yourself.”

Professor Mezzacappa becomes the fourth member of the current physics faculty elected to AAAS Fellowship, joining Professors Elbio Dagotto, Adriana Moreo, and Hanno Weitering.