Faculty Profile

A STAR AMONG STARGAZERS

UNIVERSITY OF MIAMI COSMOLOGIST JOSHUA GUNDERSEN SHARES THE GALAXY WITH HIS STUDENTS

By Robert C. Jones, Jr.

In the late 1970s, the stargazing parties staged at the La Crosse branch of the University of Wisconsin were a popular draw for many of the town’s residents. One of them was a kid named Joshua Gundersen, an eighth-grader fascinated by the planets and the stars. Gundersen’s interest in astronomy led him to the Massachusetts Institute of Technology, where he graduated in 1988 with an S.B. in physics. He received a Ph.D. in physics from the University of California, Santa Barbara, in 1995.

Now a professor of physics at the College of Arts & Sciences, Gundersen has come a long way in better understanding what often lies light-years away. “I remember attending planetarium shows as a child and writing a paper about cosmology,” Gundersen recalls, noting that his interest in the subject was kindled by Carl Sagan’s book Cosmos.

Gundersen is part of an international research team, headed by principal investigator, Mark Devlin, from the University of Pennsylvania, that built an innovative new telescope called BLAST (Balloon-borne Large-Aperture Sub-millimeter Telescope) and in 2006 launched it to the edge of the atmosphere. The size of a Ford Explorer, BLAST soared 120,000 feet above Antarctica and proceeded to take measurements of light, at three different sub-millimeter wavelengths, emitted from the far reaches of space. The data it captured revealed a new class of so-called “starburst” galaxies that are located some 5–10 billion light years from Earth, produce stars at an incredible rate, and hide about half of the starlight in the cosmos.

“By going to balloon altitudes, we got nice crystal-clear pictures,” Gundersen explained. He collaborated with graduate student Nicholas Thomas, who went to Antarctica to prepare the telescope for its 11-day flight. Some of the results of their subsequent work were published in the April 9, 2009, issue of Nature.

Gundersen enjoys teaching and interacting with students at all levels. “I have both undergraduate and graduate students who work in my lab. They tend to be very dedicated and diligent, willing to work long hours to get an experiment built, analyze the data, or operate equipment in the field,” he said. “I’ve also taught large undergraduate courses. It’s always a great joy to watch students look through telescopes and see such phenomena as Saturn’s rings for the first time and say, ‘Wow, this is the COOLEST thing I’ve ever seen!”

In addition to BLAST, Gundersen is working on a project, called the Q/U Imaging Experiment (QUIET), to detect and characterize polarization in the cosmic-microwave background—i.e., the remnant glow from the Big Bang. The experiment is based in the Atacama Plateau in the high Chilean Andes and is searching for the signature of primordial gravity waves that are emitted in the first instant of the Big Bang.

Meanwhile, rich data recently released after two years of Gundersen’s extensive analysis of BLAST is being combined with information from other NASA observatories (such as the Spitzer Space Telescope and the Chandra X-ray Observatory). This information should help astronomers and cosmologists better understand the evolutionary history of starburst galaxies and how they may be associated with larger-scale structures in the universe. “We only have a good handle on about five percent of the contents of the universe,” Gundersen said. “I think there are many surprises around the corner.”