Dan Werthimer has spent more than four decades trying to eavesdrop on aliens.
A pioneering researcher in the field of astronomy known as SETI, or the search for extraterrestrial intelligence, Werthimer's work involves scanning the cosmos with huge, ground-based radio telescopes to look for strange or unexplained signals that may have originated from alien civilizations.
If it sounds a bit like looking for a needle in a haystack, that's because it sort of is.
In recent years, however, the search for extraterrestrial intelligence has become even more complicated. Increasing demands for mobile services and wireless internet have crowded the radio spectrum, creating interference that can skew data and add "noise" to scientific results.
"Earth is just getting more and more polluted," said Werthimer, chief technologist at the Berkeley SETI Research Center. "With some radio bands, it's already impossible to do SETI because they're so full of television transmitters, WiFI and cellphone bands."
As wireless technologies continue to grow, the problem will only get worse, Werthimer said, potentially jeopardizing one of the key ways that scientists have to search for intelligent life in the universe.
Werthimer was recently one of the authors of a pre-print study led by Chinese researchers that identified a radio signal that several news outlets mistakenly reported as having characteristics of an alien civilization. The signal was actually found to have been radio interference, Werthimer clarified.
Focused SETI research began in earnest in the 1980s, and was cemented in popular culture with the 1985 novel "Contact" by Carl Sagan, which was later adapted into a film in 1997 starring Jodie Foster.
At its heart, SETI research aims to answer the question: Are we alone in the universe? In the decades since scientists first started listening for alien signals, improvements in telescope technology and data processing have bolstered the search, Werthimer said.
"We used to listen to one channel, and now we're listening to 10 billion channels," he said. "The technology and science keeps improving."
Those leaps in technology, however, have come with their share of challenges. More satellites are being launched into low-Earth orbit than ever before as a result of falling launch costs and cheaper materials to build spacecraft. Society's growing reliance on wireless internet and GPS navigation also means more competition for radio frequencies.