The Breakthrough Listen project is the largest and most comprehensive search for extraterrestrial intelligence (SETI) ever undertaken. Launched in 2015 with $100 million in funding from Russian billionaire Yuri Milner and Stephen Hawking, Breakthrough Listen aims to dramatically expand the search for signs of intelligent life beyond Earth using some of the most powerful telescopes and data analysis methods available.
Telescopes and Instruments
Breakthrough Listen has partnered with major observatories around the world to gain access to cutting-edge radio telescopes and optical telescopes. These facilities provide unprecedented sensitivity for detecting even faint or distant signals that could indicate the presence of extraterrestrial technology.
Key radio telescopes being used by Breakthrough Listen include:
- The Green Bank Telescope in West Virginia, which offers high sensitivity across 1-4 GHz frequencies. Breakthrough Listen has dedicated observing time on this telescope.
- The Parkes Telescope in Australia, capable of surveying large swaths of the sky rapidly at wide bandwidths. A new phased array feed increases its field of view.
- The upgraded MeerKAT telescope array in South Africa, whose 64 radio dishes can cover huge sky areas for a SETI survey of 1 million stars.
On the optical side, Breakthrough Listen uses the Automated Planet Finder telescope at Lick Observatory in California. This sensitive instrument can detect laser pulses originating from another civilization, if they exist.
Instruments have been customized to maximize their performance for a SETI search. This includes ultra wide-bandwidth digital backends and streamlined data pipelines to generate and analyze petabytes of data.
Search Targets and Strategies
Breakthrough Listen’s primary search targets include:
- One million of the closest stars to Earth
- The plane of the Milky Way galaxy
- The galactic center
- Nearby galaxies including Andromeda and Triangulum
This encompasses a vast volume of space – over 1000 times larger than previous SETI searches – based on regions considered more likely to host intelligent life.
Different search strategies are tailored to these regions. Nearby stars are scanned broadly over 1-12 GHz frequencies at high sensitivity. The galactic plane is surveyed more shallowly but over wider bandwidths from 1-93 GHz. And nearby galaxies are examined over 1-3 GHz for exceptionally strong signals.
As data is collected, machine learning algorithms and other techniques filter out interference and extract candidate signals meriting further study as potential evidence of extraterrestrial technology.
Findings and Future Directions
Thus far Breakthrough Listen has detected over 4 million signal “hits” warranting investigation, though almost all have proved to originate from human-made radio frequency interference. Nevertheless, the project has placed upper limits on the presence of various transmitter types around target stars.
One intriguing signal detected in 2019 from Proxima Centauri is still undergoing analysis. While the signal is likely interference, it spurred development of a rigorous framework to verify true extraterrestrial signals.
As it enters its second half in the 2020s, Breakthrough Listen continues to refine strategies and pursue new observing partnerships to maximize chances for detection. Key goals include completing the 1 million star survey using MeerKAT, increasing optical observations, and releasing more data to engage machine learning researchers and citizen scientists alike in the search.
Conclusion
The Breakthrough Listen initiative has revitalized SETI with an unprecedented scale of funding, instrumentation and scientific focus. While the odds of success remain uncertain, its comprehensive approach across radio and optical wavelengths provides the best opportunity yet to finally answer the question, “Are we alone?” The next few years of observations offer exciting potential for a discovery that would truly be a breakthrough moment in human history. Fortune