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Breakthrough Listen

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The Green Bank Telescope is one of the radio telescopes used by the project.

Breakthrough Listen is a project to search for intelligent extraterrestrial communications in the Universe.[1][2] With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities,[3] it is the most comprehensive search for alien communications to date.[1][2] The project began in January 2016, and is expected to continue for 10 years.[4] It is a component of Yuri Milner's Breakthrough Initiatives program. The science program for Breakthrough Listen is based at Berkeley SETI Research Center,[5][6] located in the Astronomy Department[7] at the University of California, Berkeley.

The project uses radio wave observations from the Green Bank Observatory and the Parkes Observatory, and visible light observations from the Automated Planet Finder.[8] Targets for the project include one million nearby stars and the centers of 100 galaxies. All data generated from the project are available to the public, and SETI@Home (BOINC) is used for some of the data analysis. The first results were published in April 2017, with further updates expected every 6 months.[6]


The project aims to discover signs of extraterrestrial civilizations by searching stars and galaxies for radio signals and laser transmissions. The search for radio signals is carried out on the Green Bank Telescope in the Northern Hemisphere and the Parkes Telescope in the Southern Hemisphere. The Green Bank Telescope is the world's largest steerable radio telescope, and the Parkes Telescope is the second-largest steerable radio telescope in the Southern Hemisphere.[9][10]

Together, the radio telescopes will cover ten times more sky than previous searches and scan the entire 1-to-10 GHz range, the so-called "quiet zone" in the spectrum where radio waves are unobscured by cosmic sources or Earth's atmosphere.[11]

The radio telescopes are sensitive enough to detect "Earth-leakage" levels of radio transmission from stars within 5 parsecs,[4] and can detect a transmitter of the same power as a common aircraft radar from the 1,000 nearest stars.[12] The Green Bank Telescope began operations in January 2016, and the Parkes Telescope from October 2016.[4] The FAST radiotelescope in China also joined forces in October 2016 with the Breakthrough Initiatives to launch a coordinated search, including the rapid sharing of promising new signals for additional observation and analysis.[13]

The search for optical laser transmissions is carried out by the Automated Planet Finder of Lick Observatory.[14] The telescope has the sensitivity to detect a 100 watt laser from a star 25 trillion miles (4.25 light years) away.[12]


Physicist Stephen Hawking was among the scientists who co-signed an open letter of support for Breakthrough Listen.

Breakthrough Listen was announced to the public on July 20, 2015 (the anniversary of the Apollo 11 Moon landing) by Milner at London's Royal Society. The event was flanked by scientists such as Frank Drake, who is known for the Drake equation that estimates the number of detectable alien civilizations, and Geoff Marcy, an astronomer who has helped find hundreds of exoplanets.[15] The announcement included an open letter co-signed by multiple scientists, including physicist Stephen Hawking, expressing support for an intensified search for alien life.[1][16] During the public launch, Hawking said:

In an infinite Universe, there must be other life. There is no bigger question. It is time to commit to finding the answer.[1]


The project is the most comprehensive search for alien communications to date.[1] It is estimated that the project will generate as much data in one day as previous SETI projects generated in one year.[1] Compared to previous programs, the radio surveys cover 10 times more of the sky, at least 5 times more of the radio spectrum, and work 100 times faster.[14] The optical laser survey is also the deepest and broadest search in history.[14]

Andrew Siemion, director of the Berkeley SETI Research Center at the University of California, Berkeley, describes that "We would typically get 24–36 hours on a telescope per year, but now we'll have thousands of hours per year on the best instruments...It's difficult to overstate how big this is. It's a revolution."[17]


As of April 2016, the targets for the radio search with the Green Bank Radio Telescope in the Northern Hemisphere include the following:[4]

The Parkes Radio Telescope will cover similar targets in the Southern Hemisphere from 1–4 GHz, and also the galactic plane and center.[4]

The targets for the Automated Planet Finder will closely match those of the Green Bank radio search, with small adjustments due to the telescope's much smaller field of view.[4]

While the telescopes are observing, the current targets of the Green Bank Radio Telescope and the Automated Planet Finder can be viewed live at the Berkeley Seti Research Center.[citation needed]

In January 2017, the project published its initial targets, which are the 60 nearest stars and a further 1649 stars which are the closest representatives of each spectral type.[18] The initial targets also include 123 galaxies which cover all morphological types of galaxies.[18]

In October 2019 it was announced that Breakthrough Listen will collaborate with scientist from NASA's Transiting Exoplanet Survey Satellite (TESS) team. Over a thousand new planets found by TESS will be scanned for technosignatures. The search will use Listen's primary facilities (Green Bank and Parkes Telescopes, MeerKAT, and the Automated Planet Finder) as well as partner facilities (including VERITAS, NenuFAR, FAST, the Murchison Widefield Array, LOFAR stations in Ireland and Sweden, Jodrell Bank Observatory, e-MERLIN, Keck Observatory, Sardinia Radio Telescope, along with the Allen Telescope Array). In addition to targeting of TESS planets with Listen facilities, the TESS lightcurves themselves will be searched for anomalies, for example caused by megastructures.[19][20]

Breakthrough Listen Exotica Catalog[edit]

Breakthrough Listen Exotica Catalog is a list of 700 targets that were chosen "to include "one of everything" in the observed Universe – ranging from comets to galaxies, from mundane objects to the most rare and violent celestial phenomena".[21][22][23]

There are four types of targets in the catalog:[21]

  1. "Prototypes: a list containing at least one example of every known kind of celestial object (apart from those too transient to present realistic observation targets). Planets and moons, stars at every point of their life cycle, galaxies big and small, serene star clusters and blazing quasars, and more are all included in the list."
  2. "Superlatives: objects with the most extreme properties. These include examples like the hottest planet, stars with unusually high or low metal content, the most distant quasar and fastest-spinning pulsar, and the densest galaxy."
  3. "Anomalies: enigmatic targets whose behavior is currently not satisfactorily explained. For instance, the famous "Tabby's Star" with its bizarre dimming behavior; ’Oumuamua – the interstellar object that passed near Earth in 2017; unexplained optical pulses that last mere nanoseconds; and stars with excess infrared radiation that could conceivably be explained as waste heat from alien megastructures."
  4. A control sample of sources not expected to produce positive results.

Data processing[edit]

Analyzing radio observations for possible signals requires intensive data analysis to cover all of the possible signal types. To carry out an in-depth search, the data recorder at the Green Bank telescope has been significantly upgraded.[24] The system records 6 GHz of bandwidth at 24GB of data per second, making it among the highest data rate recording systems in radio astronomy, and there is a plan to double its capabilities in the near future.[24] Once this data has been recorded, it is analysed for signals using a computing cluster with 64 GTX 1080 GPUs.[24] The raw data is reduced to a lower resolution to allow long-term storage, but even this reduced data totals approximately 1 petabyte per year.[25]

All data generated from Breakthrough Listen project will be open to the public.[26] The data is uploaded on the initiative's Open Data Archive, where any user can download it for software analysis. Breakthrough Initiatives are developing open source software to assist users in understanding and analyzing the data, which are available on GitHub under UCBerkeleySETI.[26]

The data is also processed by the SETI@home (BOINC) volunteer computer network, with the first batch of data being made available to SETI@home in April 2016.[4]


The project is funded with $100 million from Yuri Milner.[27] One third of this funding will be used to purchase telescope time.[28] So far, the project has signed contracts for around 20 percent of the time on the Green Bank Telescope for the next five years, and 25 percent of the time on the Parkes Telescope.[9][29] Another third will be used for the development of new equipment to receive and process potential signals,[28] and the final third will be used to hire astronomy staff.[30]

Project leadership[edit]

Among the projects leaders are:[citation needed]

  • Frank Drake, chairman emeritus, SETI Institute; professor emeritus of astronomy and astrophysics, University of California, Santa Cruz; founding director, National Astronomy and Ionosphere Center; former Goldwin Smith Professor of Astronomy, Cornell University.
  • Ann Druyan, creative director of the Voyager Interstellar Message, NASA Voyager; co-founder and CEO, Cosmos Studios; Emmy Award- and Peabody Award-winning writer and producer.
  • Martin Rees, Astronomer Royal, Fellow of Trinity College; emeritus professor of cosmology and astrophysics, University of Cambridge.
  • Andrew Siemion, director, Berkeley SETI Research Center.[31]
  • Dan Werthimer, co-founder and chief scientist of the SETI@home project; director of SERENDIP; principal investigator for CASPER.
  • Pete Worden, chairman, Breakthrough Prize Foundation.


  • In April 2017, the project released its first set of results, covering the observations of 692 nearby stars at frequencies from 1.1–1.9 GHz (the L-band).[6][32] These observations included 11 events which passed the threshold for significance, but it was concluded that they were all consistent with radio frequency interference.[32] A summary of the observations and the raw data relating to them has been published online.[33] The project plans to continue publishing updated results approximately every 6 months.[6]

The project has begun at lower frequencies as these have a lower frequency range which is easier to record and process, and plans eventually to observe in a wide range of frequencies from 1.15 GHz to 93 GHz.[24]

  • On August 30, 2017, Breakthrough Listen said it picked a series of 15 radio bursts coming from a dwarf galaxy about 3 billion light years away.[34] Breakthrough Listen researchers said the possibility of the source being extraterrestrial life cannot yet be ruled out.[needs update] The radio emissions were detected by the Green Bank Telescope in West Virginia. The source is FRB 121102 which was already known but the activity was vastly different in the latest findings.[citation needed]
  • In December 2017, Breakthrough Listen observed ʻOumuamua, an interstellar asteroid with an unusually elongated shape, for any signs of radio emissions.[35] Over eight hours of observing over a range of frequencies from 1.1–11.6 GHz, no emissions were detected.[36]
  • In December 2018, a search for laser light emissions from Boyajian's Star was carried out using the Automated Planet Finder, which is sensitive enough to detect a 24 MW laser at this distance. Although a number of candidates were identified, further analysis showed that they are coming from the Earth and not from the star.[37]
  • In January 2020, a preliminary results for the nearby (<150 parsecs away) stars were announced, with no positive detections of artificial transmitters comparable to the terrestrial Arecibo Observatory in the 3.95-8.00 GHz band. Also, it was concluded that at least 8% of 252 nearby stars in a zone allowing detection of Earth by occultation method do not have the 100%-duty (artificial) transmitters of the sort sought by the survey.[38][clarification needed]
  • In December 2020, it was reported that in April and May 2019, a narrowband signal at 982.002 MHz was intercepted that showed shifts in its frequency consistent with the movement of a planet. No modulation was detected.[39] The signal appears to have originated from the direction of Proxima Centauri. It has been given the name Breakthrough Listen Candidate 1 (BLC1). As of December 2020, the researchers were still working to rule out terrestrial interference, which they considered the most likely cause. One researcher called it "on par" with the Wow! signal.[40][41][needs update]
  • In May 2022, Breakthrough Listen conducted the first targeted search for the Wow! Signal.[42] It was its first collaboration between the Green Bank Telescope and the SETI Institute's Allen Telescope Array.[43] The observations lasted 1 hour from Greenbank, 35 minutes from ATA, and 10 minutes simultaneously.[44] No technosignature candidates were found.[45]

See also[edit]


  1. ^ a b c d e f Merali, Zeeya (20 July 2015). "Search for extraterrestrial intelligence gets a $100-million boost. Russian billionaire Yuri Milner announces most comprehensive hunt for alien life". Nature. 523 (7561). Nature News: 392–3. Bibcode:2015Natur.523..392M. doi:10.1038/nature.2015.18016. PMID 26201576.
  2. ^ a b Rundle, Michael (20 July 2015). "$100m Breakthrough Listen is 'largest ever' search for alien civilisations". Wired. Retrieved 20 July 2015.
  3. ^ Chethan Kumar (August 31, 2017). "Breakthrough detects 15 radio bursts from dwarf galaxy; might be from 'alien' spacecraft". Times of India.
  4. ^ a b c d e f g "Breakthrough Listen Initiative Publicly Sharing Data from Unprecedented Search for Intelligent Life in the Universe". Breakthrough Initiatives. April 12, 2016. Retrieved 2016-04-14.
  5. ^ "Berkeley SETI". seti.berkeley.edu. Retrieved 2017-09-21.
  6. ^ a b c d "Breakthrough Listen Initiative Publishes Initial Results". Breakthrough Initiatives. April 20, 2017. Retrieved 2017-09-21.
  7. ^ "Breakthrough Listen Initiative – News from Department of Astronomy". astro.berkeley.edu. Retrieved 2017-09-21.
  8. ^ Sample, Ian (20 July 2015). "Anybody out there? $100m radio wave project to scan far regions for alien life". The Guardian. Retrieved 20 July 2015.
  9. ^ a b "Green Bank Telescope Joins 'Breakthrough Listen' – NRAO: Revealing the Hidden Universe". public.nrao.edu. Retrieved 2016-04-14.
  10. ^ "Telescopes". Breakthrough Listen. Retrieved 2016-04-14.
  11. ^ Zhang, Sarah (2015-07-20). "A Russian Tycoon Is Spending $100 Million to Hunt for Aliens". WIRED. Retrieved 2016-04-14.
  12. ^ a b Brodkin, Jon (2015-07-20). "$100 million search for aliens will listen for messages from 100 galaxies". Ars Technica. Retrieved 24 July 2015.
  13. ^ "National Astronomical Observatories of China, Breakthrough Initiatives Launch Global Collaboration in Search for Intelligent life in the Universe" (Press release). Breakthrough Initiatives. 12 October 2016. Retrieved 2016-10-14 – via Astrobiology Web.
  14. ^ a b c "Listen". Breakthrough Listen. Retrieved 2016-04-14.
  15. ^ Zhang, Sarah (2015-07-20). "A Russian Tycoon Is Spending $100 Million to Hunt for Aliens". Wired. Retrieved 11 August 2015.
  16. ^ Vella, Matt (21 July 2015). "Read the Inspiring 'Questions of Existence' Letter from the World's Greatest Thinkers". Time. Retrieved 21 July 2015.
  17. ^ Merali, Zeeya (2015). "Search for extraterrestrial intelligence gets a $100-million boost". Nature. 523 (7561): 392–393. Bibcode:2015Natur.523..392M. doi:10.1038/nature.2015.18016. PMID 26201576.
  18. ^ a b Howard Isaacson; Andrew P. V. Siemion; Geoffrey W. Marcy; Matt Lebofsky; Danny C. Price; et al. (2017). "The Breakthrough Listen Search for Intelligent Life: Target Selection of Nearby Stars and Galaxies". Publications of the Astronomical Society of the Pacific. 129 (975): 054501. arXiv:1701.06227. Bibcode:2017PASP..129e4501I. doi:10.1088/1538-3873/aa5800. S2CID 119077156.
  19. ^ Observatory, Green Bank (2019-10-23). "Breakthrough Listen Announces New Collaboration". Green Bank Observatory. Retrieved 2020-01-10.
  20. ^ "Breakthrough Listen Releases its one-of-Everything "Exotica" Catalog". Universe Today. 5 July 2020. Retrieved 13 May 2022.
  22. ^ Lacki, Brian C.; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia Z.; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete (1 December 2021). "One of Everything: The Breakthrough Listen Exotica Catalog". The Astrophysical Journal Supplement Series. 257 (2): 42. arXiv:2006.11304. Bibcode:2021ApJS..257...42L. doi:10.3847/1538-4365/ac168a. S2CID 219966544.
  23. ^ "One Of Everything: The Breakthrough Listen Exotica Catalog - Astrobiology". astrobiology.com. 23 June 2020. Retrieved 13 May 2022.
  24. ^ a b c d David H.E. MacMahon; Danny C. Price; Matthew Lebofsky; Andrew P. V. Siemion; Steve Croft; et al. (2018). "The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope". Publications of the Astronomical Society of the Pacific. 130 (986): 044502. arXiv:1707.06024. Bibcode:2018PASP..130d4502M. doi:10.1088/1538-3873/aa80d2. S2CID 59378232.
  25. ^ Yunfan Gerry Zhang; Ki Hyun Won; Seung Woo Son; Andrew Siemion; Steve Croft (2019). "Self-Supervised Anomaly Detection for Narrowband SETI". arXiv:1901.04636 [astro-ph.IM].
  26. ^ a b "Open Data". Breakthrough Initiatives. Archived from the original on 2016-04-16. Retrieved 2016-04-14.
  27. ^ Toor, Amar (2015-07-20). "Yuri Milner will spend $100 million to look for aliens". The Verge. Retrieved 24 July 2015.
  28. ^ a b ""Breakthrough Listen": Giant Leap for SETI". Sky & Telescope. 2015-07-22. Retrieved 2016-04-14.
  29. ^ CSIRO. "CSIRO and Internet investor Yuri Milner strike deal for ET search". csiro.au. Retrieved 2016-04-14.
  30. ^ Overbye, Dennis (2015-07-20). "Stephen Hawking Joins Russian Entrepreneur's Search for Alien Life". The New York Times. ISSN 0362-4331. Retrieved 2016-04-14.
  31. ^ "Yuri Milner and Stephen Hawking Announce $100 Million Breakthrough Initiative to Dramatically Accelerate Search for Intelligent Life in the Universe". Breakthrough Initiatives. July 20, 2015. Retrieved 2015-07-24.
  32. ^ a b J. Emilio Enriquez; Andrew Siemion; Danny C. Price; David Macmahon; Matt Lebofsky; et al. (April 21, 2017). "The Breakthrough Listen Search for Advanced Life: 1.1–1.9Ghz Observations of 692 Nearby Stars" (PDF) (Draft) – via berkeley.edu.
  33. ^ "Breakthrough Listen: L-band 2017". seti.berkeley.edu. Retrieved 2021-03-09.
  34. ^ "Alien-hunting Breakthrough Listen project tracks strange series of 15 radio bursts". GeekWire. 2017-08-30. Retrieved 2017-09-01.
  35. ^ Sample, Ian (December 11, 2017). "Astronomers to check interstellar body for signs of alien technology". The Guardian. Retrieved 2017-12-12. Green Bank telescope in West Virginia will listen for radio signals from 'Oumuamua, an object from another solar system ... "Most likely it is of natural origin, but because it is so peculiar, we would like to check if it has any sign of artificial origin, such as radio emissions," said Avi Loeb, professor of astronomy at Harvard University and an adviser to the Breakthrough Listen project. "If we do detect a signal that appears artificial in origin, we'll know immediately." ... While many astronomers believe the object is an interstellar asteroid, its elongated shape is unlike anything seen in the asteroid belt in our own solar system. Early observations of 'Oumuamua show that it is about 400m long but only one tenth as wide. "It's curious that the first object we see from outside the solar system looks like that," said Loeb.
  36. ^ J. E. Enriquez; A. Siemion; T. J. W. Lazio; M. Lebofsky; D. H. E. MacMahon; et al. (2018). "Breakthrough Listen Observations of 1I/′Oumuamua with the GBT". Research Notes of the American Astronomical Society. 2 (1): 9. arXiv:1801.02814. Bibcode:2018RNAAS...2....9E. doi:10.3847/2515-5172/aaa6c9. S2CID 119435272.
  37. ^ David Lipman; Howard Isaacson; Andrew P. V. Siemion; Matt Lebofsky; Danny C. Price; et al. (2018). "The Breakthrough Listen Search for Intelligent Life: Searching Boyajian's Star for Laser Line Emission". Publications of the Astronomical Society of the Pacific. 131 (997): 034202. arXiv:1812.10161. doi:10.1088/1538-3873/aafe86. S2CID 119476899.
  38. ^ Sheikh, Sofia Z.; Siemion, Andrew; Emilio Enriquez, J.; Price, Danny C.; Isaacson, Howard; Lebofsky, Matt; Gajjar, Vishal; Kalas, Paul (2020). "The Breakthrough Listen Search for Intelligent Life: A 3.95-8.00 GHZ Search for Radio Technosignatures in the Restricted Earth Transit Zone". The Astronomical Journal. 160 (1): 29. arXiv:2002.06162. Bibcode:2020AJ....160...29S. doi:10.3847/1538-3881/ab9361. S2CID 211126496.
  39. ^ Overbye, Dennis (31 December 2020). "Was That a Dropped Call From ET? - A spooky radio signal showed up after a radio telescope was aimed at the next star over from our sun". The New York Times. Retrieved 31 December 2020.
  40. ^ O'Callaghan, Jonathan; Billings, Lee. "Alien Hunters Discover Mysterious Signal from Proxima Centauri". Scientific American. Retrieved 19 December 2020.
  41. ^ "Scientists looking for aliens investigate radio beam 'from nearby star'". The Guardian. 2020-12-18. Retrieved 2020-12-18.
  42. ^ "1st Coordinated Green Bank Telescope/Allen Telescope Array Observes Possible Source of the WOW! Signal".
  43. ^ Elizabeth Howell (2022-11-07). "No signs of alien life found near source of famous 'Wow!' signal". Space.com. Retrieved 2022-11-13.
  44. ^ Perez, Karen I. (2022). "Breakthrough Listen Search for the WOW! Signal". AAS. 6 (9): 197. Bibcode:2022RNAAS...6..197P. doi:10.3847/2515-5172/ac9408. S2CID 252540293.
  45. ^ "Breakthrough Listen Search for the WOW! Signal". seti.berkeley.edu. Retrieved 2022-11-13.

External links[edit]