New software developed to search for periodic signals from alien civilizations

The Breakthrough Listen Investigation for Periodic Spectral Signals (BLIPSS), led by Akshay Suresh, a doctoral candidate in astronomy at Cornell University, is at the forefront of a groundbreaking search for periodic signals originating from the heart of our galaxy, the Milky Way. This research aims to detect repetitive patterns as a means of seeking out potential signs of extraterrestrial intelligence (SETI) within our cosmic neighborhood.

The team of researchers has developed sophisticated software based on the Fast Folding Algorithm (FFA), an efficient search method that significantly enhances sensitivity to periodic sequences of narrow pulses. Their recent publication, titled “A 4–8 GHz Galactic Center Search for Periodic Technosignatures,” was released on May 30 in The Astronomical Journal.

Pulsars, which are rapidly rotating neutron stars that emit beams of radio energy that sweep across the Earth, serve as natural astrophysical objects that generate periodic signals. However, directed periodic transmissions are also used by humans for various applications, including radar. Such signals could serve as an effective way to attract attention across interstellar space, distinguishing themselves from the background of non-periodic signals while utilizing considerably less energy than a continuously broadcasting transmitter.

Suresh stated, “BLIPSS exemplifies the utilization of cutting-edge software as a multiplier for SETI research. Our study introduces the Fast Folding Algorithm to SETI for the first time, and our open-source software enables us to process over 1.5 million time series for periodic signals in approximately 30 minutes.”

Detection of a target periodic spectral signal using blipss. Left: simulated radio frequency-time data containing 64 spectral channels of width 391 kHz each. A periodic pulsed signal has been inserted into the central channel. Right: radio frequency-period (P) diagram showing the detection of a P0 = 30 s signal in the central spectral channel. The first harmonic (cross) and the first subharmonic (plus) of the fundamental signal frequency (f0 = 1/P0) are also detected at P = 15 s and P = 60 s, respectively. Credit: The Astronomical Journal (2023). DOI: 10.3847/1538-3881/acccf0

BLIPSS is a collaborative initiative involving Cornell University, the SETI Institute, and Breakthrough Listen. This project represents a significant advancement in the quest for evidence of extraterrestrial technology by focusing on the densely populated central region of the Milky Way, which is known to host numerous stars and potentially habitable exoplanets. The central region of our galaxy is also an ideal location for potential alien civilizations to place beacons, allowing them to communicate with a vast portion of the Galaxy.

To validate their algorithm, the team conducted tests on known pulsars and successfully detected the expected periodic emissions. They then expanded their analysis to a larger dataset obtained from scans of the Galactic Center using the Breakthrough Listen instrument installed on the 100-meter Green Bank Telescope (GBT) located in West Virginia. Unlike pulsars, which emit signals across a wide range of radio frequencies, BLIPSS focused on identifying repetitive signals within a narrower frequency range, covering less than a tenth of the bandwidth of an average FM radio station.

Co-author Steve Croft, Breakthrough Listen project scientist, emphasized, “The combination of these relatively narrow bandwidths with periodic patterns could potentially indicate deliberate technological activities by intelligent civilizations.” He further explained that Breakthrough Listen captures vast amounts of data, and Akshay’s technique offers a new method to search through this data haystack in the pursuit of valuable evidence of advanced extraterrestrial life.

Co-author Vishal Gajjar, an astronomer at the SETI Institute, highlighted the energy efficiency of periodic pulses as a means of interstellar communication over vast distances. He stated, “Until now, radio SETI has primarily focused on the search for continuous signals. Our study reveals the remarkable energy efficiency of a train of pulses for interstellar communication. Importantly, this research represents the first comprehensive endeavor to conduct in-depth searches for such signals.”

Source: Cornell University

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