Science in the City: The Hamilton Spectator's Steve Buist interviews Ralph Pudritz

Ralph Pudritz

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Heather Sheardown

Mehran Anvari

Ralph Pudritz

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Science in the CIty
Overview & Schedule

Ralph Pudritz

The following article is reprinted courtesy of the Hamilton Spectator, McMaster University’s partner in the Science in the City Lecture Series.

News, Monday, May 12, 2003
Mac prof will take his listeners to the stars

Steve Buist
The Hamilton Spectator

Ralph Pudritz is prepared to share a little secret with you tomorrow night. He's going to reveal how a star is born.

But his recipe for stardom won't include good looks, a decent singing voice or even being the last person left standing on Survivor. Instead, he'll talk about the kind of stars that are born from giant clouds of gases that extend over trillions of kilometres of the cosmos and radiation and spinning molecules of carbon monoxide.

Pudritz, a professor in McMaster University's department of physics and astronomy, will be delivering a lecture tomorrow night in The Spectator auditorium entitled Lighting up the Cosmos: The Origins and History of Star Formation in the Universe.

It's part of the Science in the City lecture series, which is sponsored jointly by McMaster and The Spectator.

"Star formation is one of the great problems in astronomy," said Pudritz, who joined the department in 1986.

"It's been on the minds of astronomers for as long as there has been astronomy."

Stars form out of dense clouds of gas and dust that extend over vast stretches of the universe. A typical giant molecular cloud, as they're called, might have a total weight a million times greater than our sun but spread over a billion billion kilometres.

"These clouds are among the most massive beasts in any galaxy," he said.

As subregions of these clouds bang together, they eventually become dense enough that they collapse together under their own weight to form a star or more typically a cluster of stars. The region closest to us in the galaxy that's forming a cluster containing some massive stars is in the Orion nebula.

"If your readers look out at Orion constellation and look at the tip of the sword of Orion, that is where a famous cluster called the Orion nebula cluster is in the act of forming," said Pudritz.

"This is a major laboratory for us to study how star formation works in detail. In cosmic and astronomical terms, it's very rapid but you won't see it zip together in your lifetime."

One of the difficulties that people stumble over with astronomy is the sheer magnitude of time and space. It's a field where time is counted in the millions and billions of years and distance is measured by the parsec -- the distance light would travel in 3.26 years. That is about 30,000,000,000,000,000 kilometres, give or take a kilometre.

"You have to try to find ways of grasping scales, numbers, times that are very different than our own life cycles and things we're familiar with on earth. I always try to do this with students I teach, to get them to develop a physical feeling of this."

He uses the example of the Orion nebula cluster of stars that have been forming for about a million years or so. Our earliest human-like ancestors have been around for longer than that.

"So the very first intelligent beings that maybe could start to make sense of the night sky in our own evolution would have looked up towards Orion and not seen that cluster there yet."

Perhaps more than other scientific disciplines, astronomy brings to centre stage some of the big-ticket questions about life. "In many ways, that's why I went into astronomy in the first place," Pudritz said. "I feel that at the heart of it, astronomy and astrophysics has been our oldest science.

"Trying to contemplate the universe has always been one of our greatest sources of scientific discovery."

And then, of course, there are the biggest of the big-ticket questions.

How does theology fit into astronomy and the study of the cosmos? How did all these gases and particles and molecules get there in the first place?

"That's always just beneath the surface of fundamental science," said Pudritz. "This focus on origins, as we call it, is very deep in astronomy."

Pudritz will talk about star formation and how some of the oldest star systems formed. "And from that, we'll go back to the very first star. It should be pretty interesting."

The lecture is free and open to the public.

To register for a spot, call 905-525-9140 ext. 24934 or e-mail at sciencecity@mcmaster.ca. Doors open at 6:30 p.m.; the session starts at 7 p.m.

sbuist@thespec.com or 905-526-3226.