Physics Professor Rick Watkins
Canvassing the Cosmos
Physics Professor Rick Watkins is not one to limit the scope of his research. In fact, it's tough to get much broader than his area of interest: the universe.
"When I told my father that I study the universe, he laughed," Watkins says. "He thought it was a joke. He said, 'How can anybody study the universe?'"
The subject may sound all-encompassing, but Watkins' actual work is narrowly focused. The cosmologist uses scientific observations to study the universe as a whole. Cosmology is based on the idea that the entire history of the universe, starting with the Big Bang, is governed by physical laws.
"As a system, the universe is pretty simple," Watkins says. "I'm mostly interested in galaxies. The Milky Way is roughly shaped like a Frisbee, and we're located about two-thirds of the way out from the center of the disc. If you went outside the Milky Way, you'd find there aren't many stars between the galaxies. So once you're looking at that large of a scale, you're basically just watching a bunch of galaxies moving through space."
Watkins is a theorist who tries to make sense of the data collected about these galaxies' movements. He examines how the galaxies are distributed throughout space, which way they're moving and why. As gravity pulls on the galaxies, they flow toward regions of the universe that contain more mass, creating clusters of galaxies and leaving nearly empty space behind.
If you're concerned about us being on a collision course with another galaxy, you shouldn't be. At least not now. Our nearest neighbor, Andromeda, is about 2.5 million light-years away. Yes, it and the Milky Way are moving toward each other, but don't worry, Watkins says. "If they do collide, it won't be for another 3 billion years or so."
Galaxies move at hundreds of kilometers per second, but because they're so far away, we can't see them flow. Instead, scientists track their motion using the Doppler shift, the same concept that makes a train whistle's pitch change as it whooshes past. A galaxy's light shifts toward the red or blue end of the spectrum depending on whether it's moving closer or farther away.
Cosmology also provides revelations about the early history of the universe. The galaxies scientists observe are millions, sometimes billions of light years away. The most distant galaxies scientists can see appear as they did billions of years ago, when the light started traveling away from them, providing clues to how the universe has changed.
"The general trend is that as you go back in time, the universe becomes smoother instead of having these clumps of galaxies," Watkins says. "The early universe was filled with a dense, hot, uniform gas. It was very different than the universe we see around us today."
When he's not pondering the universe, Watkins can be found playing Ultimate Frisbee with Willamette students. This is his eighth year as the Ultimate Frisbee Club faculty advisor and his 20th playing the sport. He's also a popular speaker at a local middle school, where he has visited several times to introduce the students to cosmology.
"The nice thing about being a cosmologist is that almost everyone is interested in the universe. The middle-schoolers always have interesting questions. Some of them have done a lot of reading, and I'm always surprised about how much they know."