Pittsburgh Review

Clouds hid most of the April 8 solar eclipse for Carnegie Mellon University physics senior Norris Bach. But from his vantage in rural Texas Hill Country, he still had a thrill. Bach was there with a team of researchers chasing a phenomenon known as shadow bands. "The view from the ground was obscured by a dense layer of clouds," Bach said. "We did get to briefly see the eclipse peak through the clouds several times, and the darkness of totality was truly a sight to behold. The overcast conditions prevented us from seeing any shadow bands on the ground, but our balloon produced great data that we are currently analyzing."

David Turnshek, a professor of physics and astronomy at the University of Pittsburgh, and his team of researchers are challenging the traditional explanation for shadow bands. "His team's 2017 observations, obtained from a high-altitude balloon at 80,000 feet, indicated that the turbulent layer in the troposphere wasn’t causing the shadow bands; rather they primarily originate above the Earth’s atmosphere." Turnshek's alternative theory led to the formation of the Pitt Shadow Bandits, a team that includes Jeffrey Peterson, a professor of physics at Carnegie Mellon, who helped develop instrumentation for the project.

"Over the years, I've built a large variety of instrumentation in the service of a particular cosmological problem," said Peterson. "The science comes first, and if I can figure out a clever use of an antenna or a nice trick with the electronics, I can work with a student to design and test it."

The collaborative effort of the Pitt Shadow Bandits during the recent solar eclipse involved launching high altitude balloons equipped with instrumentation to collect data. Despite challenges with cloud cover, the team managed to recover sensors and is now in the process of analyzing the data collected. "It's exciting to look for the shadow bands from the stratosphere," Peterson said. "Looking at new data is like unwrapping a present; you don't know what to expect."

Turnshek emphasized the importance of collaboration in the success of the experiment. "Norris and the other students optimized the configurations of our light sensors, which were the most important part of the project," Turnshek said. "Jeff has been invaluable to our efforts as we've been guided by his strong technical background as we developed low noise light sensors to study the shadow bands."

The researchers are hopeful that their findings will provide insight into the physics behind shadow bands. Bach expressed his excitement about the potential impact of their research, stating, "Being able to determine the actual physics behind them is really exciting. We might be able to close the book on this."