An intriguing potential signal detected by the Breakthrough Listen project last year has been subjected to extensive investigation, indicating that it is unlikely to have originated from the Proxima Centauri system. According to the Breakthrough Initiatives, it looks to be a relic of Earth-based influence from human technologies. Two studies published in Nature Astronomy detail the identification of the candidate signal as well as an enhanced data analysis approach that can precisely distinguish false positives.
According to Yuri Milner, the importance of this finding is that the hunt for civilizations beyond our planet is now a mature, rigorous discipline of experimental research.
Breakthrough Listen is an astronomical scientific initiative that looks for technosignatures, which are indications of technology generated by an alien civilization. Listen’s science team, led by Dr. Andrew Siemion of the University of California, Berkeley, captures data across broad swaths of the radio spectrum in the direction of a diverse range of celestial targets using some of the world’s largest radio telescopes outfitted with the most capable digital processing systems. The search is difficult since the Earth is inundated with radio waves from human technology, such as cell phones, radar, satellites, and TV transmitters.
Looking for a weak signal from a distant star is like looking for a needle in a big digital haystack that changes all the time. Breakthrough Listen’s search includes the CSIRO Parkes Telescope. Proxima Centauri, the Sun’s nearest neighboring star at a distance of slightly over 4 light-years, is one of the objects Parkes is keeping an eye on. Two known exoplanets orbit the star, which is a red dwarf. The Listen team scanned the target throughout a frequency range of 700 MHz to 4 GHz which is the equivalent of turning to nearly 800 million radio channels at the same time, with the help of exceptional detection sensitivity.
Shane Smith, an undergraduate researcher in the summer 2020 Breakthrough ‘Listen’ internship program working with Listen Project Scientist Dr. Danny Price, processed the data from these observations using Breakthrough Listen’s search pipeline. He discovered approximately 4 million frequency bands with radio emission signals.
The Listccasually a fascinating signal remains and must be investigated further. Smith detected such a signal-of-interest while using the Parkes telescope to observe Proxima Centauri. A narrow-band, Doppler-drifting signal that seemed to be present exclusively in “ON” observations of the target star and not in the intermittent “OFF” data showed some of the features predicted of a techno signature candidate, persisting throughout five hours of observations.
Dr. Sofia Sheikh, a postdoctoral researcher with the UC Berkeley Listen team, dived into a wider collection of observations made at previous periods.
Breakthrough Listen is helping in releasing the scanned data for the public to examine for themselves. The team has also just released two articles detailing the data gathering and analysis, as well as a research note documenting follow-up observations of Proxima Centauri using the Parkes Telescope in April 2021. Listen will continue to observe Proxima Centauri, which remains an intriguing target for techno signature searches, with a global network of telescopes. Furthermore, the team is constantly refining algorithms to increase their performance, notably as part of a recently finished crowdsourced data processing competition.