Researchers at the SETI Institute have developed an innovative method to filter through cosmic signals and potentially identify messages from extraterrestrial life. Their new technique, known as the “twinkle test,” utilizes data from a pulsar star, tracking subtle variations in its radio signals over an extended period. This groundbreaking approach could enhance the search for alien signals while contributing to the broader field of astronomy.
The study commenced in February 2023, when a team led by Grayce Brown focused on the pulsar PSR J0332+5434. Situated over 3,000 light-years from Earth, this particular pulsar is notable for its rapid spin and is the brightest pulsar observable using the SETI-operated Allen Telescope Array in California. Over the course of 10 months, the team meticulously monitored the pulsar’s radio emissions, revealing how interstellar gas can slightly alter the arrival time of its signals.
The research identified that the gas between stars can shift the timing of a pulsar’s radio waves by billionths of a second. These minute delays, referred to as scintillation, mimic the twinkling effects seen in stars from Earth. As the pulsar, Earth, and interstellar gas move relative to each other, fluctuations occur, creating bright and dim patches in the radio waves. Such patterns can significantly impact when the signals arrive, leading to discrepancies that can hinder the detection of faint extraterrestrial signals.
In a statement reported by Space.com, Brown emphasized the importance of their findings: “Pulsars are wonderful tools that can teach us much about the universe and our own stellar neighbourhood.” She elaborated that these results not only advance pulsar science but also benefit various branches of astronomy, including the search for extraterrestrial intelligence.
The team conducted nearly 400 observations, which illustrated how radio waves from the pulsar’s poles travel through space, interacting with clouds of charged gas primarily composed of free electrons. This interaction causes bending, scattering, and delays that can obscure signals from potential extraterrestrial sources. If these scintillation effects are not taken into account, they may mask the very signals SETI researchers are trying to detect.
The SETI Institute noted that this research provides a crucial tool for distinguishing between terrestrial radio signals and those from distant star systems. “Noticeable scintillation can help SETI scientists differentiate human-made radio signals from those of extraterrestrial origin,” the institute stated. Brown explained further, “Because of this research, we know how much scintillation to expect from a radio signal traveling through this pulsar’s region of interstellar space. If we don’t see that scintillation, then the signal is probably just interference from Earth.”
The findings from this significant study were published in The Astrophysical Journal on December 10, 2023. As the quest for extraterrestrial life continues, the “twinkle test” could pave the way for more effective searches, offering hope for discovering signals beyond our Solar System.
