March 3, 2008
Radio telescope tunes into galaxy
By Carol Clark
In the beginning, there was hydrogen.
“It’s the original element,” says Ray DuVarney, associate professor and chair of physics. “If you start with hydrogen, everything else happens. It’s amazing, but that’s all you need. For example, you can form a star.”
Hydrogen is the simplest and most prolific element in the universe. The sun is a giant ball of hydrogen and helium, while the center of our galaxy contains an intense, swirling cloud of hydrogen gas. Although invisible to optical instruments, the hydrogen at the heart of the galaxy emits 21-centimeter radio waves that pass through the cosmic dust of the Milky Way.
The astronomy program in the Department of Physics recently recorded an image of these radio waves, using a radio telescope built through the labor and ingenuity of faculty and staff.
“This is a big boon for our astronomy students,” DuVarney says of the program’s new technology.
Emory already has a state-of-the-art observatory and optical telescope, which reflects visible light. The radio telescope, and its ability to track invisible energy, adds a whole new dimension to teaching and research.
“For instance, what you see optically when you look toward the center of our galaxy is just a big, bright blob, because it’s so densely packed with stars and materials,” explains Horace Dale, an astronomer and physics research associate. “Radio astronomy allows us get through all that to determine more about what’s going on in the center, in terms of composition and relative motion. It gives our students a better perspective of the dynamics of our galaxy.”
The quest to retrofit a rusting, 25-foot satellite dish atop the Peavine Parking Deck and turn it into a radio telescope began in 2004. Visionaries from physics and Facilities Management had the notion of bringing a new life and purpose to the broken-down satellite dish – once used by Emory scholars to monitor broadcasts from the Soviet Union. Brainstorming sessions were held over pitchers of beer in the now defunct Park Bench pub.
“I used to get a lot of problems solved at Park Bench,” DuVarney says. “I miss it.”
The idea paid off a few weeks ago, when the improvised radio telescope passed its first test run. Four people worked nearly four hours to do the painstaking job of using a grid system to track 21-centimeter hydrogen radio waves across the sky and produce a radio image, featuring the sun and center of the galaxy.
“We’ve proved that we can do it,” Dale says. “We’ve turned the dish into a radio telescope. Now we just have to make it more user friendly.” All physics undergraduate students will have access to the telescope beginning in the fall, and plans call for eventually making it operable via remote control and the Internet.