Working with an international team of physicists and astronomers, University of Richmond physics professor Ted Bunn assisted in the construction of a new instrument that will help the team measure radiation left over from the early universe, just after the Big Bang.

The instrument was moved this summer to its final location, for use in a radio telescope in the mountains of Argentina, where it is undergoing testing and commissioning. 

Bunn explained that around 13 billion years ago, or roughly 380,000 years after the Big Bang, the expanding universe had cooled enough to condense from hot, thick plasma into atoms and neutral particles that allowed light to pass through it. Some of the light from that time is still arriving at the Earth today and is known as the cosmic microwave background radiation.

Capturing this radiation gives astronomers a glimpse of what the cosmos looked like way back then, what Bunn jokingly referred to as “the universe’s baby pictures.”   

The cosmology project, called QUBIC, began in 2008 and has grown to include over 100 researchers from 20 universities in Argentina, Italy, France, the U.K., and the U.S.

Bunn was an early member of the collaboration, and he played a unique role in the project. While many members of the group were observational astronomers specializing in data analysis, instrument building, or electronics, Bunn was good at solving very complex math problems. He describes himself as the group’s “pet theorist.”

Bunn’s work was crucial in the early stages of the project’s development, as he worked out how to optimize an array of antennas to collect the maximum possible amount of useful data, a key step in setting the project on a path toward success. Bunn included UR undergraduate students in his research throughout his participation in the project.

The collaboration’s new instrument, a millimeter-wavelength interferometer, is designed to measure tiny variations in the polarization of the cosmic microwave background radiation. Patterns in these tiny variations may give scientists clues to help them understand how the universe expanded during the first fraction of a second. The instrument’s completion marks an important milestone and will be significant to many astrophysicists over the years to come.

“It’s exciting to be playing a part in measurements that have the potential to enhance our understanding of the universe,” Bunn said.