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词条 Breakthrough Listen
释义

  1. Overview

  2. Announcement

  3. Significance

  4. Targets

  5. Data processing

  6. Funding

  7. Project leadership

  8. Results

  9. See also

  10. References

  11. External links

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,[2] it is the most comprehensive search for alien communications to date.[1][3] The project began in January 2016, and is expected to continue for 10 years.[6] It is a component of Yuri Milner's Breakthrough Initiatives program. The science program for Breakthrough Listen is based at Berkeley SETI Research Center,[4][8] located in the Astronomy Department[5] 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.[6] 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 is used for some of the data analysis. The first results were published in April 2017, with further updates expected every 6 months.[8]

Overview

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 telescope in the Southern Hemisphere.[7][8]

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.[9]

The radio telescopes are sensitive enough to detect "Earth-leakage" levels of radio transmission from stars within 5 parsecs,[6] and can detect a transmitter of the same power as a common aircraft radar from the 1,000 nearest stars.[10] The Green Bank Telescope began operations in January 2016, with the Parkes Telescope due to join it in October 2016.[6] 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.[11]

The search for optical laser transmissions is carried out by the Automated Planet Finder of Lick Observatory.[19] The telescope has the sensitivity to detect a 100 watt laser from a star 25 trillion miles (4.25 light years) away.[10]

Announcement

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.[12] 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][13] During the public launch, Hawking said:

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

Significance

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."[15]

Targets

As of April 2016, the targets for the radio search with the Green Bank Radio Telescope in the Northern Hemisphere include the following:[6]

  • All 43 stars within 5 parsecs
  • 1000 stars of all spectral-types within 50 parsecs
  • One million nearby stars
  • Center regions of at least 100 nearby galaxies, including spiral galaxies, elliptical galaxies, dwarf galaxies and irregular galaxies
  • Exotic Stars: 20 white dwarfs, 20 neutron stars, 20 black holes

The Parkes Radio Telescope will cover similar targets in the Southern Hemisphere from 1–4 GHz, and also the galactic plane and center.[6]

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.[6]

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.

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[16]. The initial targets also include 123 galaxies which cover all morphological types of galaxies[16].

Data processing

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[17]. The system records 6GHz 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[17]. Once this data has been recorded, it is analysed for signals using a computing cluster with 64 GTX 1080 GPUs.[17] 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.[18]

All data generated from Breakthrough Listen project will be open to the public.[19] 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.[19]

The data is also processed by the SETI@home volunteer computer network, with the first batch of data being made available to SETI@home in April 2016.[20]

Funding

The project is funded with $100 million from Yuri Milner.[21] One third of this funding will be used to purchase telescope time.[22] 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.[7][23] Another third will be used for the development of new equipment to receive and process potential signals,[22] and the final third will be used to hire astronomy staff.[24]

Project leadership

  • 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.[25]
  • 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.

Results

In April 2017, the project released its first set of results, covering the observations of 692 nearby stars at frequencies from 1.1–1.9GHz (the L-band).[26][50] These observations included 11 events which passed the threshold for significance, but it was concluded that they were all consistent with radio frequency interference.[27] A summary of the observations and the raw data relating to them has been published online. The project plans to continue publishing updated results approximately every 6 months.[26]

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 1.15GHz to 93GHz.[17]

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.[28] Breakthrough Listen researchers said the possibility of source being extraterrestrial life can't be ruled out as yet. 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.

In December 2017, Breakthrough Listen observed ʻOumuamua, an interstellar asteroid with an unusually elongated shape, for any signs of radio emissions.[29] Over 8 hours of observing over a range of frequencies from 1.1–11.6 GHz, no emissions were detected.[30]

In December 2018, a search for laser light emissions from Bayajian'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.[31]

See also

{{Portal|Astrobiology}}
  • Communication with extraterrestrial intelligence
  • Nexus for Exoplanet System Science
  • Ohio State University Radio Observatory
  • Open data, Open-source software
  • Search for extraterrestrial intelligence

References

1. ^1 2 3 4 5 {{cite web|url=http://www.nature.com/news/search-for-extraterrestrial-intelligence-gets-a-100-million-boost-1.18016?WT.mc_id=TWT_NatureNews|title=Search for extraterrestrial intelligence gets a $100-million boost. Russian billionaire Yuri Milner announces most comprehensive hunt for alien life.|last=Merali|first=Zeeya |date=20 July 2015|publisher=Nature News|accessdate=20 July 2015}}
2. ^{{cite web |url=http://timesofindia.indiatimes.com/home/science/breakthrough-detects-15-radio-bursts-from-dwarf-galaxy-might-be-from-alien-spacecraft/articleshow/60296645.cms |author=Chethan Kumar |title=Breakthrough detects 15 radio bursts from dwarf galaxy; might be from 'alien' spacecraft |date=August 31, 2017 |work=Times of India}}
3. ^1 {{cite web |url=https://www.wired.co.uk/news/archive/2015-07/20/breakthrough-listen-project|title=$100m Breakthrough Listen is 'largest ever' search for alien civilisations |last=Rundle |first=Michael |date=20 July 2015 |work=Wired|accessdate=20 July 2015}}
4. ^{{Cite web |url=https://seti.berkeley.edu/listen/ |title=Berkeley SETI |website=seti.berkeley.edu |language=en |access-date=2017-09-21}}
5. ^{{Cite web |url=http://astro.berkeley.edu/p/breakthrough-listen |title=Breakthrough Listen Initiative - News from Department of Astronomy |website=astro.berkeley.edu |access-date=2017-09-21}}
6. ^{{cite web |url=https://www.theguardian.com/science/2015/jul/20/breakthrough-listen-massive-radio-wave-project-scan-far-regions-for-alien-life |title=Anybody out there? $100m radio wave project to scan far regions for alien life |last=Sample |first=Ian |date=20 July 2015 |publisher=The Guardian |accessdate=20 July 2015}}
7. ^1 {{Cite web |url=https://public.nrao.edu/news/pressreleases/gbt-breakthrough-listen |title=Green Bank Telescope Joins 'Breakthrough Listen' - NRAO: Revealing the Hidden Universe |website=public.nrao.edu |access-date=2016-04-14}}
8. ^{{Cite web |url=http://breakthroughinitiatives.org/Telescopes/1 |title=Telescopes |website=Breakthrough Listen |access-date=2016-04-14}}
9. ^{{Cite web|url=https://www.wired.com/2015/07/russian-tycoon-spending-100-million-hunt-aliens/|title=A Russian Tycoon Is Spending $100 Million to Hunt for Aliens|website=WIRED|language=en-US|access-date=2016-04-14}}
10. ^1 {{cite web|last=Brodkin|first=Jon|title = $100 million search for aliens will listen for messages from 100 galaxies|url = https://arstechnica.com/science/2015/07/100-million-search-for-aliens-will-listen-for-messages-from-100-galaxies/|publisher=Ars Technica|accessdate = 24 July 2015}}
11. ^{{cite press release |url=http://astrobiology.com/2016/10/national-astronomical-observatories-of-china-breakthrough-initiatives-launch-global-collaboration-in.html |title=National Astronomical Observatories of China, Breakthrough Initiatives Launch Global Collaboration in Search for Intelligent life in the Universe |publisher=Breakthrough Initiatives |via=Astrobiology Web |date=12 October 2016 |accessdate=2016-10-14 }}
12. ^{{cite web|url = https://www.wired.com/2015/07/russian-tycoon-spending-100-million-hunt-aliens/|title = A Russian Tycoon Is Spending $100 Million to Hunt for Aliens|accessdate = 11 August 2015|work =Wired |last = Zhang|first = Sarah}}
13. ^{{cite web|last1=Vella|first1=Matt|title=Read the Inspiring 'Questions of Existence' Letter from the World's Greatest Thinkers|url=http://time.com/3964301/breakthrough-listen-letter/|work=Time|accessdate=21 July 2015|date=21 July 2015}}
14. ^1 2 {{Cite web |url=http://breakthroughinitiatives.org/Initiative/1|title=Listen |website=Breakthrough Listen |access-date=2016-04-14}}
15. ^{{Cite web|url=http://www.nature.com/news/search-for-extraterrestrial-intelligence-gets-a-100-million-boost-1.18016|title=Search for extraterrestrial intelligence gets a $100-million boost|website=Nature News & Comment|access-date=2016-04-14}}
16. ^1 {{Cite journal |arxiv=1701.06227 |display-authors=5 |author1=Howard Isaacson |author2=Andrew P. V. Siemion |author3=Geoffrey W. Marcy |author4=Matt Lebofsky |author5=Danny C. Price |author6=David MacMahon |author7=Steve Croft |author8=David DeBoer |author9=Jack Hickish |author10=Dan Werthimer |author11=Sofia Sheikh |author12=Greg Hellbourg |author13=J. Emilio Enriquez |title=The Breakthrough Listen Search for Intelligent Life: Target Selection of Nearby Stars and Galaxies |journal=Publications of the Astronomical Society of the Pacific |volume=129 |issue=975 |pages=054501 |doi=10.1088/1538-3873/aa5800 |year=2017 }}
17. ^1 2 3 {{Cite journal |arxiv=1707.06024 |display-authors=5 |author1=David H.E. MacMahon |author2=Danny C. Price |author3=Matthew Lebofsky |author4=Andrew P. V. Siemion |author5=Steve Croft |author6=David DeBoer |author7=J. Emilio Enriquez |author8=Vishal Gajjar |author9=Gregory Hellbourg |author10=Howard Isaacson |author11=Dan Werthimer |author12=Zuhra Abdurashidova |author13=Marty Bloss |author14=Ramon Creager |author15=John Ford |author16=Ryan S. Lynch |author17=Ronald J. Maddalena |author18=Randy McCullough |author19=Jason Ray |author20=Mark Whitehead |author21=Dave Woody |title=The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope |journal=Publications of the Astronomical Society of the Pacific |volume=130 |issue=986 |pages=044502 |archive-url=|archive-date=|dead-url=|access-date=|doi=10.1088/1538-3873/aa80d2 |year=2018 }}
18. ^{{cite arxiv |eprint=1901.04636 |title=Self-Supervised Anomaly Detection for Narrowband SETI |author1=Yunfan Gerry Zhang |author2=Ki Hyun Won |author3=Seung Woo Son |author4=Andrew Siemion |author5=Steve Croft |class=astro-ph.IM |year=2019 }}
19. ^1 {{Cite web |url=http://breakthroughinitiatives.org/OpenData/1 |website=Breakthrough Initiatives |title=Open Data |access-date=2016-04-14}}
20. ^1 2 3 4 5 6 {{Cite web |url=http://breakthroughinitiatives.org/News/3 |website=Breakthrough Initiatives |title=Breakthrough Listen Initiative Publicly Sharing Data from Unprecedented Search for Intelligent Life in the Universe |date=April 12, 2016 |access-date=2016-04-14}}
21. ^{{cite web|last=Toor|first=Amar|title = Yuri Milner will spend $100 million to look for aliens|url = https://www.theverge.com/2015/7/20/9002339/yuri-milner-alien-search-breakthrough-listen|website = The Verge|accessdate = 24 July 2015}}
22. ^1 {{Cite web|url=http://www.skyandtelescope.com/astronomy-news/breakthrough-listen-a-giant-leap-for-seti/|title="Breakthrough Listen": Giant Leap for SETI - Sky & Telescope|website=Sky & Telescope|language=en-US|access-date=2016-04-14}}
23. ^{{Cite web|url=http://csiro.au/en/News/News-releases/2015/CSIRO-and-Internet-investor-Yuri-Milner-strike-deal-for-ET-search|title=CSIRO and Internet investor Yuri Milner strike deal for ET search|last=CSIRO|website=csiro.au|language=en-AU|access-date=2016-04-14}}
24. ^{{Cite news|url=https://www.nytimes.com/2015/07/21/science/yuri-milner-russian-entrepreneur-promises-100-million-for-alien-search.html|title=Stephen Hawking Joins Russian Entrepreneur's Search for Alien Life|last=Overbye|first=Dennis|date=2015-07-20|newspaper=The New York Times|issn=0362-4331|access-date=2016-04-14}}
25. ^{{cite web |url=http://www.breakthroughinitiatives.org/News/1 |title=Yuri Milner and Stephen Hawking Announce $100 Million Breakthrough Initiative to Dramatically Accelerate Search for Intelligent Life in the Universe |website=Breakthrough Initiatives |date=July 20, 2015 |accessdate=2015-07-24}}
26. ^1 2 3 {{Cite web |url=https://breakthroughinitiatives.org/News/10 |title=Breakthrough Listen Initiative Publishes Initial Results |date=April 20, 2017 |website=Breakthrough Initiatives |access-date=2017-09-21}}
27. ^1 {{Cite web |display-authors=5 |author1=J. Emilio Enriquez |author2=Andrew Siemion |author3=Danny C. Price |author4=David Macmahon |author5=Matt Lebofsky |author6=Howard Isaacson |author7=Greg Hellbourg |author8=Vishal Gajjar |author9=Steve Croft |date=April 21, 2017 |title=The Breakthrough Listen Search for Advanced Life: 1.1–1.9Ghz Observations of 692 Nearby Stars |type=Draft |url=http://blpd0.ssl.berkeley.edu/lband2017/Lband_BL_SETI_Submitted_Draft.pdf |via=berkeley.edu}}
28. ^{{Cite news|url=https://www.geekwire.com/2017/alien-hunting-breakthrough-listen-project-tracks-strange-series-15-radio-bursts/|title=Alien-hunting Breakthrough Listen project tracks strange series of 15 radio bursts|date=2017-08-30|work=GeekWire|access-date=2017-09-01|language=en-US}}
29. ^{{cite web |url=https://www.theguardian.com/science/2017/dec/11/astronomers-to-check-interstellar-body-for-signs-of-alien-technology |title=Astronomers to check interstellar body for signs of alien technology |first=Ian |last=Sample |publisher=The Guardian |date=December 11, 2017 |accessdate=2017-12-12 |quote=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.}}
30. ^{{Cite arxiv |eprint=1801.02814 |display-authors=5 |author1=J. E. Enriquez |author2=A. Siemion |author3=T. J. W. Lazio |author4=M. Lebofsky |author5=D. H. E. MacMahon |author6=R. S. Park |author7=S. Croft |author8=D. DeBoer |author9=N. Gizani |author10=V. Gajjar |author11=G. Hellbourg |author12=H. Isaacson |author13=D. C. Price |title=Breakthrough Listen Observations of 1I/′Oumuamua with the GBT |class=astro-ph.EP |year=2018}}
31. ^{{cite arxiv |eprint=1812.10161 |display-authors=5 |author1=David Lipman |author2=Howard Isaacson |author3=Andrew P. V. Siemion |author4=Matt Lebofsky |author5=Danny C. Price |author6=David MacMahon |author7=Steve Croft |author8=David DeBoer |author9=Jack Hickish |author10=Dan Werthimer |author11=Greg Hellbourg |author12=J. Emilio Enriquez |author13=Nectaria Gizani |title=The Breakthrough Listen Search for Intelligent Life: Searching Boyajian's Star for Laser Line Emission |class=astro-ph.IM |year=2018 }}

External links

  • Breakthrough Listen, Breakthrough Initiatives website
{{Astrobiology}}{{Extraterrestrial life}}{{Interstellar messages}}

2 : Search for extraterrestrial intelligence|Interstellar messages
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