Rob Thacker discusses the role of computers in astrophysics research. Photo: Terrence McEachern

Harnessing computers a big challenge in astrophysics: prof

Rob Thacker says re-creating the universe is a lot like predicting the weather.

Both use numerical models and computer simulations. Both also start with what they already know. For meteorology, it may be what the weather was like yesterday or the day before. For astrophysics, it is about 300,000 to 400,000 years after the Big Bang.

But there is a difference between the two. The meteorologist only has to wait one day to see if the prediction was correct.

This is where the use of supercomputers in astrophysics is beneficial for researchers. "Now you can compresses billions of years into a few seconds," said Thacker, an associate professor of astrophysics at Saint Mary's University and Canada Research Chair in Astronomy and Astrophysics.

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Dal student Kathryn Foote looks at the moon through a telescope after Friday night's lecture. Photo: Terrence McEachern

Thacker made the remarks as part of a lecture given Friday night before a crowd of more than 200 people at SMU. He says the advantage of using supercomputers in astrophysics is that they allow researchers to input data, and create models and simulations of how galaxies and stars are formed as well as how the universe has evolved. They also allow researchers to solve equations they couldn't otherwise solve "on a blackboard or with a pen and paper."

But the problem is that as computer technology advances, computers become more complex and difficult to program, said Thacker. Supercomputers used to be one computer with a powerful processor. Now, supercomputers are numerous computers with powerful processors connected together. This has made running programs on the computers harder, he said.

"You have to make sure that all of the work you're doing in your simulations is evenly spread out, because as soon as you have things that aren't doing anything, your total power going into the computation is going down," said Thacker.

"Really, a lot of people who work on this are borderline computer scientists as well as physicists."

If computer technology continues to evolve at the same rate it has over the past 30 years, the implications for astrophysics could be significant. "We could model individual galaxies where you could see the clouds collapsing down to form stars," he said.

Thacker first became interested in astronomy and astrophysics after watching Carl Sagan's 1980 TV miniseries Cosmos as a 10-year-old living in England.

Now, at 38, Thacker's interest in the stars has led to partnerships with other provincial universities and institutions through Astronomy Nova Scotia as well as nationally and internationally with the University of California at Berkeley, the University of Pittsburgh, the University of Toronto and the Max Planck Society in Germany.

Thacker's lecture, called "Computing the Cosmos: From the Big Bang to Galaxies" is part of a regional effort to celebrate the 2009 International Year of Astronomy. The series celebrates 400 years after Galileo created his first telescope and began his astronomical discoveries.

Thacker says he's thrilled with the response the series has received so far. "I was absolutely delighted that over 200 people showed up, as we were marginally worried what the attendance might be," he said.

"I view communication of my research as important as conducting the research itself, so when we reach out to the public and they come and attend events like this, the experience is incredibly rewarding for me and I hope them as well."

Kathryn Foote, a dental hygiene student at Dalhousie University, attended the lecture. "I thought it was really good," she said.
"I always wanted to take an astronomy class but I never got to ... It's really nice to get to hear of the latest stuff in lay terms but still enough to be interesting."

The next regional lecture in the series is by astronomer David Levy Feb. 10 at Acadia University.

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