Reaching for the Stars
Willamette University student Ben Zeiger went to the New Mexico desert to see the galaxies with radio telescopes. He didn't find any aliens, but he did find a method of examining violent explosions that occurred at least 100,000 years ago.
Zeiger, a senior physics major, recently returned from a summer internship at the National Radio Astronomy Observatory in Socorro, a small town 75 miles south of Albuquerque. He won a grant for a National Science Foundation Research Experience for Undergraduates (REU), a national program that provides real-world research experiences for college-age scientists. The internship, which paid a stipend as well as Zeiger's travel and housing expenses, gave the young researcher his first real look into space.
"Astronomy has been an area of interest of mine since high school," he says. "This was my first chance to see what real astronomy is like."
Zeiger joined seven other undergraduates and three graduate students from across the country at the Very Large Array (VLA), a y-shaped network of 27 radio telescopes. Each 230-ton antenna has an 82-foot dish and, when arrayed together, they search the skies with the resolution of a 22-mile wide antenna. "Optical astronomy sees high energy wavelengths that are short, approximately a nanometer long," he explains. "Radio astronomy is different in that it looks at very long wavelength light, which is very low energy. It lets you see things that don't give off much radiation like galaxies and clouds of dense hydrogen."
Zeiger's project involved studying an oddly shaped supernova remnant (SNR), a cloud surrounding a star that ran out of energy, exploded and collapsed in on itself at least 100,000 years ago. Curiously, Zeiger's SNR didn't expand equally in all directions, but instead formed both a higher-density inner hydrogen cloud and a lower-density outer cloud. Zeiger wanted to find out why.
"We know there shouldn't be this interior hydrogen cloud because it should have been blown off during the initial explosion," he explains. "But we can see an inner cloud because it's got a higher temperature and gives off more radiation than the outer cloud."
When Zeiger's star exploded, the central portion of the star collapsed under gravity forming a dense neutron star, also called a pulsar. "The center of the star collapsed so much that protons and electrons squished together to form neutrons," he says. "Pulsars have very strong magnetic fields and electrons travel along magnetic fields. That's how we get the Aurora Borealis; electrons from the sun travel around the North Pole, combine and accelerate, giving off the pretty colors. These stars also create auroras that we can see from several thousand light years away. Because these neutron stars spin, they flash light at us 25 times a second like a lighthouse."
Zeiger's idea for studying this neutron star was to analyze its movement over time. "I took observations from the VLA archives and compared images from 1987 to 2003," he explains. "Using the position of 15 other stars as a reference, I wanted to see where the cloud and the pulsar had moved in that time."
So what did the young astronomer find? His work supports the current model for the behavior of supernova remnants. "The data suggest that the star's explosion ran into a dense hydrogen cloud within the supernova remnant, which changed the cloud's shape," he says.
In addition to his original research, Zeiger says he and the other students were given four hours of actual observation time on the VLA. "We could work on any project we decided on as a group," he says, showing off computer-generated, other-worldly images - giant red and yellow amoebas, feathery swirls of cotton candy, ribbons of ethereal light. "When data comes in from each pair of telescopes, it's just a data point for every 10 seconds. Since the wavelengths are impossible to see, you can modify the data into images of the sky."
Another highlight for Zeiger was exploring the Southwest. "We went to White Sands, the place where they tested the atomic bomb," he says, displaying pictures of gleaming white mountains of sand. "We went to the Grand Canyon and Carlsbad Canyon."
Perhaps his most surreal field trip was a stop in Roswell, N.M., made famous in 1947 by the crash of a UFO some believe was an alien space ship. "Roswell was really great," says Zeiger smiling broadly. "This museum tour guide was convinced he was from Pleiades. He had this whole cosmology he'd developed about how the aliens are using the earth as a reservoir of the universe's DNA. He believes it would be a perfect world if an asteroid hadn't carried in amino acids and proteins that cause diseases. That conversation was certainly a highlight."
Whether it's science or science fiction, Zeiger says his astronomical experience has changed him. "I haven't made any career decisions yet, but this experience gave me a different perspective about future directions. Before this, I didn't even know what a working scientist looked like. Now, chances are good that I'll end up going into graduate school to study astrophysics."