Associate Professor of Physics Jonathan Pober has spent the past 20 years detecting faint astronomical signals in radio waves that can provide information about the early universe.
This task can be challenging due to interference from much larger radio waves in the Earth’s atmosphere and in outer space. But Pober and Jade Ducharme GS, a physics PhD student, recently published a study bringing them one step closer to removing these interferences — all because of an airplane.
Pober works with Murchison Widefield Array, a radio telescope in Australia. Unlike the more commonly known optical telescopes — which use cameras and lenses to detect light — radio telescopes use antennas to collect radio wave data, he explained.
His work focuses on overcoming radio frequency interference, or “anything that is generated by humans that is not an astronomical signal,” so their radio telescopes are actually able to detect these astronomical signals, he said.
These faint astronomical signals can provide information about “the first stars and the first galaxies,” and how the universe developed into its current state about 13.8 billion years ago.
“The early universe looked different, and we want to know where we came from,” he said.
To understand the universe’s origins, researchers look farther out into space, which Ducharme said is analogous to looking further back in time: “If you have a star that’s 100 light years away, then you’re looking at 100 years ago.”
Specific astronomical signals are especially hard to detect because they are “needle(s) in a haystack” of radio interference, he said.
Radio interference is an increasingly significant challenge for researchers, MWA Director Steven Tingay wrote in an email to The Herald.
“It is getting to the point that there is no escape from RFI on Earth,” Tingay added.
But RFI can’t necessarily be eliminated as it is often produced by communication systems — like mobile phones and satellite communications — that “keep our societies and economies functional,” he explained.
The current radio telescopes that Pober uses do not provide precise enough data to determine which output is interference, and which “tiny, tiny part” is the target signal, he said. But developing a telescope that is precise enough could cost around $100 million, Pober estimated.
The MWA telescope detects many interferences. The challenge, then, is figuring out where the interference comes from and later removing it from the data. When the researchers realized that one particularly puzzling piece of interference was coming from an airplane in the sky, Ducharme set out to remove the piece of interfering data.
After using the radio telescope to detect the airplane, she used “geometric calculations to calculate the radius of curvature.” This feature of radio waves must later be removed from the dataset to identify the desired astronomical signals.
Although interference has barred the team from finding the astronomical signals they are looking for thus far, this study marks one step forward in deciphering the telescope data.
They are continuing the next phase of their research, applying “the lessons (they) learned” to reach their larger goals, Pober said.
“We don’t want to study airplanes,” he said. “We don’t want to study satellites. We want to study the early universe.”
