Winter 2012 - Austin College Magazine

A C E N T U R Y
celebrating
All of Don Salisbury’s 34 years of research boil down to two simple questions: Who
are we? What is our place in the universe?
With every project, the professor of physics gets a little closer to an answer—
theoretically.
Salisbury, professor of physics and a member of the Austin College faculty since
1987, specializes in the kind of theoretical physics that deals with the nature of time and
space. He tries to construct theories to explain phenomena such as black holes, dark
matter, and time travel.
The best-known leaders in his field are researchers like Stephen Hawking and
Albert Einstein. In fact, Salisbury’s thesis advisor as a graduate student was Einstein’s
assistant. Salisbury’s fundamental training in physics began with Einstein’s general
theory of relativity and has kept up ever since.
Einstein is part of Salisbury’s inspiration to keep plugging at near-impossible
problems. “Sure, he was a genius, but that characterization alone really doesn’t
illustrate the full picture. He never gave up,” Salisbury said. “The essential ingredient
is not so much inherent intelligence, because everyone has that, but it is persistence.
I think that characterizes most scientists.”
Salisbury is trying to resolve what he calls the “fundamental unsolved problem in
physics: attempting to merge Einstein’s theory of relativity with quantum mechanics.”
Quantum mechanics deals with subjects such as the structure and motion in an atom,
while Einstein’s theory is about massive objects like stars, galaxies, and even the whole
universe. “Those two theories are inconsistent with each other, and no one has yet
succeeded in synthesizing an equation that combines both,” Salisbury said.
The problem is this: Einstein’s theory says space and time don’t exist as separate,
fixed entities; time and space don’t exist outside of the universe. But quantum
mechanics depends upon the idea that time is an independent external parameter.
General relativity says that time is meaningless without a measuring device. But
quantum mechanics then says that time must be inherently uncertain. Without being
sure that time is the same everywhere, the theories completely fall apart. The
challenge is combining a theory with a flexible perspective of time with a theory with
a constant perspective.
32 | Austin College Magazine Winter 2012