Matthew Choptuik

University of British Columbia

You might say the stars guide

Matthew Choptuik’s research.

Choptuik, a professor of physics and astronomy at the University of British Columbia, delves into the components and dynamics of gravitational fields found in space.

“We focus on problems such as the formation of black holes, the interaction of black holes, the dynamics of neutron stars, the interaction of neutron stars and supernova explosions,” Choptuik says.

It’s not a stretch to say the work he does is out of this world.

“These are situations which are just not found anywhere in our local area of the universe,” he says.

A black hole is the ultimate gravitational field in space. The gravitational pull of a black hole is so strong that even light cannot escape. These are formed by the death and collapse of an extremely massive star. At this point, researchers are still in a developmental phase regarding the study of black holes and the dynamics of neutron stars. There are still many mathematical, computational and physical issues that can pose challenges. As a result, the demand for high-level computational resources is always growing.

“The problems we’re doing get larger and larger and larger,” Choptuik says. “For anybody in this kind of science it’s a never-ending need for more and more and more, but we are within view of the kind of resources we need to solve these interesting problems.”

WestGrid helps make that happen. Choptuik’s team uses WestGrid’s distributed infrastructure for many of their high level computations. For example, much of their work is continuously running nearly 100 processors across the WestGrid system.

“Many times, that’s just doing a single calculation,” Choptuik says.

In the past, before this level of computer power was available, Choptuik and his team would make assumptions to make their problems simpler. This would often reduce the computation requirements by factors of hundreds, thousands, and even millions. The ability to access WestGrid now allows them to remove those sorts of restrictions.

Probably one of the most publicized highlights in Choptuik’s career happened in 1997.

“I forced Stephen Hawking to concede a bet,” says Choptuik with a laugh.

Hawking had proposed that physical singularities could occur only inside black holes where they cannot be seen. In contrast, physicists Kip Thorne and John Preskill suggested that an observable singularity does exist. Hawking then made a bet with Thorne and Preskill in 1991.

It was Choptuik who used a supercomputer simulation to show that observable singularity could indeed exist.

“It was a mathematical demonstration but using supercomputing simulation, where I was actually also using supercomputers interactively,” Choptuik said.

Hawking was forced to concede the bet. This discovery also opened a new field of research, particularly for Choptuik’s group.

One of Choptuik’s former students, Frans Pretorius, carried Choptuik’s initial work further to implement a software infrastructure that would take full advantage of the WestGrid resources. His program opened the door for full three-dimensional simulations. Pretorius, now at the California Institute of Technology but still using WestGrid infrastructure, is currently studying a model problem for the merger of two neutron stars. He is just one example of the great strides that have been taken in this field over the last few years.

“Right now, our group is world class,” says Choptuik.

It’s that sort of momentum combined with the traditional mystique of the solar skies that helps keep Choptuik’s work in the spotlight.