
The communication with extraterrestrial intelligence (CETI) is a branch of the
search for extraterrestrial intelligence
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
(SETI) that focuses on composing and
deciphering
interstellar messages This is a list of interstellar radio messages (IRMs) transmitted from Earth.
Classification of interstellar radio messages
There are twelve realized IRM projects:
* The Morse Message (1962)
* Arecibo message (1974), one transmission to Messier ...
that theoretically could be understood by another technological civilization.
The best-known CETI experiment of its kind was the 1974
Arecibo message
The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 in 1974. It was meant as a demonstration of human technological achievement, rather than ...
composed by
Frank Drake
Frank Donald Drake (May 28, 1930 – September 2, 2022) was an American astrophysicist and astrobiologist.
He began his career as a radio astronomer, studying the planets of the Solar System and later pulsars. Drake expanded his interests ...
.
There are multiple independent organizations and individuals engaged in CETI research; the generic application of abbreviations CETI and SETI (
search for extraterrestrial intelligence
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
) in this article should not be taken as referring to any particular organization (such as the
SETI Institute
The SETI Institute is a not-for-profit research organization incorporated in 1984 whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to use this knowledge to inspire and guide present and futu ...
).
CETI research has focused on four broad areas:
mathematical
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
languages, pictorial systems such as the
Arecibo message
The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 in 1974. It was meant as a demonstration of human technological achievement, rather than ...
, algorithmic communication systems (ACETI), and computational approaches to detecting and deciphering "natural" language communication. There remain many
undeciphered writing systems
An undeciphered writing system is a written form of language that is not currently understood.
Many undeciphered writing systems date from several thousand years BC, though some more modern examples do exist. The term "writing systems" is used ...
in human communication, such as
Linear A
Linear A is a writing system that was used by the Minoans of Crete from 1800 to 1450 BC to write the hypothesized Minoan language or languages. Linear A was the primary script used in palace and religious writings of the Minoan civi ...
, discovered by archeologists. Much of the research effort is directed at how to overcome similar problems of decipherment that arise in many scenarios of interplanetary communication.
On 13 February 2015, scientists (including
Douglas Vakoch,
David Grinspoon
David H. Grinspoon (born 1959) is an American astrobiologist. He is Senior Scientist at the Planetary Science Institute and was the former inaugural Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology for 2012-2013.
His research fo ...
,
Seth Shostak
Seth Shostak (born July 20, 1943) is an American astronomer and author, and is currently the senior astronomer for the SETI Institute.
Shostak hosts SETI's weekly radio show/podcast '' Big Picture Science'', has played himself numerous times in T ...
, and
David Brin
Glen David Brin (born October 6, 1950) is an American scientist and author of science fiction. He has won the Hugo,[American Association for the Advancement of Science
The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsi ...]
, discussed active SETI and whether transmitting a message to possible intelligent
extraterrestrials
Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might ...
in the
cosmos
The cosmos (, ) is another name for the Universe. Using the word ''cosmos'' implies viewing the universe as a complex and orderly system or entity.
The cosmos, and understandings of the reasons for its existence and significance, are studied in ...
was a good idea.
That same week, a statement was released, signed by many in the SETI community, that a "worldwide scientific, political, and humanitarian discussion must occur before any message is sent".
On 28 March 2015, a related essay was written by
Seth Shostak
Seth Shostak (born July 20, 1943) is an American astronomer and author, and is currently the senior astronomer for the SETI Institute.
Shostak hosts SETI's weekly radio show/podcast '' Big Picture Science'', has played himself numerous times in T ...
and published in ''
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
''.
In June 2020, astronomers from the
University of Nottingham
The University of Nottingham is a public university, public research university in Nottingham, United Kingdom. It was founded as University College Nottingham in 1881, and was granted a royal charter in 1948. The University of Nottingham belongs t ...
reported the possible existence of over 30 "active communicating intelligent civilizations" (none within our current ability to detect due to various reasons including distance or size) in our own
Milky Way galaxy
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked ey ...
, based on the latest astrophysical information.
History
In the 19th century, many books and articles speculated about the possible inhabitants of other planets. Many people believed that intelligent beings might live on the
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...
,
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmos ...
, and/or
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...
.
Since travel to other planets was not possible at the time, some people suggested ways to signal extraterrestrials even before radio was discovered.
Carl Friedrich Gauss
Johann Carl Friedrich Gauss (; german: Gauß ; la, Carolus Fridericus Gauss; 30 April 177723 February 1855) was a German mathematician and physicist who made significant contributions to many fields in mathematics and science. Sometimes refe ...
is often credited with an
1820 proposal that a giant triangle and three squares, the
Pythagoras
Pythagoras of Samos ( grc, Πυθαγόρας ὁ Σάμιος, Pythagóras ho Sámios, Pythagoras the Samian, or simply ; in Ionian Greek; ) was an ancient Ionian Greek philosopher and the eponymous founder of Pythagoreanism. His politic ...
, could be drawn on the
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part o ...
n tundra. The outlines of the shapes would have been ten-mile-wide strips of pine forest, whereas the interiors could be filled with rye or wheat.
Joseph Johann Littrow
Joseph Johann von Littrow (13 March 1781, Horšovský Týn (german: Bischofteinitz) – 30 November 1840, Vienna) was an Austrian astronomer. In 1837, he was ennobled with the title Joseph Johann Edler von Littrow. He was the father of Karl Ludwi ...
proposed in 1819 to use the
Sahara
, photo = Sahara real color.jpg
, photo_caption = The Sahara taken by Apollo 17 astronauts, 1972
, map =
, map_image =
, location =
, country =
, country1 =
, ...
as a sort of blackboard. Giant trenches several hundred yards wide could delineate twenty-mile-wide shapes. Then the trenches would be filled with water, and then enough
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning " wax", and was reg ...
could be poured on top of the water to burn for six hours. Using this method, a different signal could be sent every night.
Meanwhile, other astronomers were looking for signs of life on other planets. In 1822,
Franz von Gruithuisen thought he saw a giant city and evidence of agriculture on the Moon, but astronomers using more powerful instruments refuted his claims. Gruithuisen also believed he saw evidence of life on
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...
.
Ashen light had previously been observed on the dark side of Venus, and he postulated that it was caused by a great fire festival put on by the inhabitants to celebrate their new emperor. Later he revised his position, stating that the Venusians could be burning their rainforest to make more farmland.
By the late 1800s, the possibility of life on the Moon was put to rest. Astronomers at that time believed in the
Kant-Laplace hypothesis, which stated that the farthest planets from the sun are the oldesttherefore Mars was more likely to have advanced civilizations than Venus.
[Owen, T. C. (2001) "Solar system: origin of the solar system", '']Encyclopædia Britannica
The ( Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various ...
'', Deluxe CDROM edition Subsequent investigations focused on contacting Martians. In 1877,
Giovanni Schiaparelli
Giovanni Virginio Schiaparelli ( , also , ; 14 March 1835 – 4 July 1910) was an Italian astronomer and science historian.
Biography
He studied at the University of Turin, graduating in 1854, and later did research at Berlin Observatory ...
announced he had discovered "canali" ("channels" in Italian, which occur naturally, and mistranslated as "canals", which are artificial) on Mars. This was followed by thirty years of enthusiasm about the possibility of
life on Mars
The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ...
. Eventually the Martian canals proved illusory.
The inventor
Charles Cros
Charles Cros or Émile-Hortensius-Charles Cros (October 1, 1842 – August 9, 1888) was a French poet and inventor. He was born in Fabrezan, Aude.
Cros was a well-regarded poet and humorous writer. As an inventor, he was interested in the fiel ...
was convinced that pinpoints of light observed on Mars and Venus were the lights of large cities. He spent years of his life trying to get funding for a giant mirror with which to signal the Martians. The mirror would be focused on the Martian desert, where the intense reflected sunlight could be used to burn figures into the Martian sand.
Inventor
Nikola Tesla
Nikola Tesla ( ; ,["Tesla"](_blank)
'' Tesla coil
A Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high-voltage, low- current, high-frequency alternating-current electricity. Tesla experimented with a number of differe ...
, used in the role of a
"resonant receiver", could be used to communicate with other planets, and that he even had observed repetitive signals of what he believed were extraterrestrial radio communications coming from Venus or Mars in 1899. These "signals" turned out to be terrestrial radiation, however.
Around 1900, the
Guzman Prize was created; the first person to establish interplanetary communication would be awarded 100,000 francs, under one stipulation: Mars was excluded because Madame Guzman thought communicating with Mars would be too easy to deserve a prize.
Mathematical and scientific languages
Lincos (Lingua cosmica)
Published in 1960 by
Hans Freudenthal
Hans Freudenthal (17 September 1905 – 13 October 1990) was a Jewish-German-born Dutch mathematician. He made substantial contributions to algebraic topology and also took an interest in literature, philosophy, history and mathematics edu ...
, ''Lincos: Design of a Language for Cosmic Intercourse'', expands upon Astraglossa to create a general-purpose language derived from basic mathematics and logic symbols. Several researchers have expanded further upon Freudenthal's work. A dictionary resembling Lincos was featured in the Carl Sagan novel ''
Contact
Contact may refer to:
Interaction Physical interaction
* Contact (geology), a common geological feature
* Contact lens or contact, a lens placed on the eye
* Contact sport, a sport in which players make contact with other players or objects
* ...
'' and
its film adaptation.
Astraglossa
Published in 1963 by
Lancelot Hogben
Lancelot Thomas Hogben FRS FRSE (9 December 1895 – 22 August 1975) was a British experimental zoologist and medical statistician. He developed the African clawed frog ''(Xenopus laevis)'' as a model organism for biological research in his ea ...
, "Astraglossa" is an essay describing a system for combining numbers and operators in a series of short and long pulses. In Hogben's system, short pulses represent numbers, while trains of long pulses represent symbols for addition, subtraction, etc.
Carl Sagan
In the 1985
science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imagination, imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, Paral ...
novel ''
Contact
Contact may refer to:
Interaction Physical interaction
* Contact (geology), a common geological feature
* Contact lens or contact, a lens placed on the eye
* Contact sport, a sport in which players make contact with other players or objects
* ...
'',
Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ...
explored in some depth how a message might be constructed to allow communication with an alien civilization, using
prime number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only way ...
s as a starting point, followed by various universal principles and facts of
mathematics and science.
Sagan also edited a nonfiction book on the subject. An updated collection of articles on the same topic was published in 2011.
A language based on the fundamental facts of science
Published in 1992 by Carl Devito and Richard Oehrle, ''A language based on the fundamental facts of science'' is a paper describing a language similar in syntax to Astraglossa and Lincos, but which builds its vocabulary around known physical properties.
Busch general-purpose binary language used in Lone Signal transmissions
In 2010, Michael W. Busch created a general-purpose binary language later used in the
Lone Signal project to transmit crowdsourced messages to extraterrestrial intelligence (METI). This was followed by an attempt to extend the syntax used in the Lone Signal hailing message to communicate in a way that, while neither mathematical nor strictly logical, was nonetheless understandable given the prior definition of terms and concepts in the Lone Signal hailing message.
Pictorial messages
Pictorial communication systems seek to describe fundamental mathematical or physical concepts via simplified diagrams sent as
bitmap
In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array or bitmap index.
As a noun, the term "bitmap" is very often used to refer to a particular bitmapping application: th ...
s. These messages necessarily assume that the recipient has similar visual capabilities and can understand basic mathematics and geometry. A common critique of pictorial systems is that they presume a shared understanding of special shapes, which may not be the case with a species with substantially different vision, and therefore a different way of interpreting visual information. For instance, an arrow representing the movement of some object might be misinterpreted as a weapon firing.
Pioneer probes
Two etched plaques, known as the
Pioneer plaque
The Pioneer plaques are a pair of gold-anodized aluminum plaques that were placed on board the 1972 ''Pioneer 10'' and 1973 ''Pioneer 11'' spacecraft, featuring a pictorial message, in case either ''Pioneer 10'' or ''11'' is intercepted by inte ...
s, were included aboard the
Pioneer 10
''Pioneer 10'' (originally designated Pioneer F) is an American space probe, launched in 1972 and weighing , that completed the first mission to the planet Jupiter. Thereafter, ''Pioneer 10'' became the first of five artificial objects to ac ...
and
Pioneer 11
''Pioneer 11'' (also known as ''Pioneer G'') is a robotic space probe launched by NASA on April 5, 1973, to study the asteroid belt, the environment around Jupiter and Saturn, solar winds, and cosmic rays. It was the first probe to encounte ...
spacecraft when they launched in 1972 and 1973. The plaques depict the specific location of the Solar System within the galaxy and the Earth within the Solar System, as well as the form of the human body.
Voyager probes
Launched in 1977, the
Voyager probes carried two
golden records
Golden Records was a Simon & Schuster record label based in New York City. It was conceived and founded in 1948 by the Grammy Award-winning children's music producer, Arthur Shimkin, then a new recruit in the S&S business department. Shimkin ...
that were inscribed with diagrams similar to the Pioneer plaques, depicting the human form, the Solar System, and its location. Also included were recordings of images and sounds from Earth.
Arecibo message
The
Arecibo message
The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 in 1974. It was meant as a demonstration of human technological achievement, rather than ...
, transmitted in 1974, was a 1,679-
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the s ...
bitmap that, when properly arranged into 73 rows and 23 columns, shows the numbers one through ten; the atomic numbers of hydrogen, carbon, nitrogen, oxygen, and phosphorus; the formulas for the sugars and bases that make up the nucleotides of DNA; the number of nucleotides in the human genome; the double helix structure of DNA; a simple illustration of a human being and its height; the human population of Earth; a diagram of the Solar System; and an illustration of the Arecibo telescope with its diameter.
Cosmic Call messages
The ''
Cosmic Call
Cosmic commonly refers to:
* The cosmos, a concept of the universe
Cosmic may also refer to:
Media
* ''Cosmic'' (album), an album by Bazzi
* Afro/Cosmic music
* "Cosmic", a song by Kylie Minogue from the album '' X''
* CosM.i.C, a member of ...
'' messages consisted of a few digital sections – "Rosetta Stone", a copy of the Arecibo Message, the Bilingual Image Glossary, and the Braastad message – as well as text, audio, video, and other image files submitted for transmission by people around the world. The "Rosetta Stone" was composed by
Stéphane Dumas and
Yvan Dutil
Yvan Dutil, born April 6, 1970, is a Canadian astrophysicist. He is a member of the Bioastronomy Commission of the International Astronomical Union and of the International Academy of Astronautics's Permanent Committee on the Search for Extra ...
, and represents a multi-page bitmap that builds a vocabulary of symbols representing numbers and mathematical operations. The message proceeds from basic mathematics to progressively more complex concepts, including physical processes and objects (such as a
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
atom). The message was designed with a noise-resistant format and characters that make it resistant to alteration by noise. These messages were transmitted in 1999 and 2003 from
Evpatoria Planetary Radar
The Yevpatoria RT-70 radio telescope (P-2500, RT-70) is an RT-70 radio telescope and planetary radar at the Center for Deep Space Communications, Yevpatoria, Crimea. In the scientific literature is often called Evpatoria Planetary Radar (EPR).
H ...
in Russia under the scientific guidance of
Alexander L. Zaitsev. Richard Braastad coordinated the overall project.
Star systems to which the messages were sent include the following:
[Передача и поиски разумных сигналов во Вселенной](_blank)
/ref>
Multi-modal messages
Teen-Age Message
The '' Teen-Age Message'', composed by Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...
n scientists ( Zaitsev, Gindilis, Pshenichner, Filippova) and teens, was transmitted from the 70-m dish of Evpatoria Deep Space Center in Ukraine
Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian invas ...
to six star systems resembling that of the Sun on August 29 and September 3 and 4, 2001. The message consists of three parts:
Section 1 represents a coherent-sounding radio signal with slow Doppler wavelength tuning to imitate transmission from the Sun's center. This signal was transmitted in order to help extraterrestrials detect the TAM and diagnose the radio propagation effect of the interstellar medium.
Section 2 is analog information representing musical melodies performed on the theremin
The theremin (; originally known as the ætherphone/etherphone, thereminophone or termenvox/thereminvox) is an electronic musical instrument controlled without physical contact by the performer (who is known as a thereminist). It is named afte ...
. This electric musical instrument produces a quasi-monochromatic signal, which is easily detectable across interstellar distances. There were seven musical compositions in the First Theremin Concert for Aliens. The 14-minute analog transmission of the theremin concert would take almost 50 hours by digital means; se
The First Musical Interstellar Radio Message
Section 3 represents a well-known Arecibo-like binary digital information: the logotype of the TAM, bilingual Russian and English greeting to aliens, and image glossary.
Star systems to which the message was sent are the following:
Cosmic Call 2 (Cosmic Call 2003) message
The Cosmic Call
Cosmic commonly refers to:
* The cosmos, a concept of the universe
Cosmic may also refer to:
Media
* ''Cosmic'' (album), an album by Bazzi
* Afro/Cosmic music
* "Cosmic", a song by Kylie Minogue from the album '' X''
* CosM.i.C, a member of ...
-2 message contained text, images, video, music, the Dutil/Dumas message, a copy of the 1974 Arecibo message, BIG = Bilingual Image Glossary, the AI program ''Ella'', and the Braastad message.
Algorithmic messages
Algorithmic communication systems are a relatively new field within CETI. In these systems, which build upon early work on mathematical languages, the sender describes a small set of mathematic and logic symbols that form the basis for a rudimentary programming language that the recipient can run on a virtual machine
In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...
. Algorithmic communication has a number of advantages over static pictorial and mathematical messages, including: localized communication (the recipient can probe and interact with the programs within a message, without transmitting a reply to the sender and then waiting years for a response), forward error correction
In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea is ...
(the message might contain algorithms that process data elsewhere in the message), and the ability to embed proxy agents within the message. In principle, a sophisticated program when run on a fast enough computing substrate, may exhibit complex behavior and perhaps, intelligence.
CosmicOS
'' CosmicOS'', designed by Paul Fitzpatrick at MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
, describes a virtual machine
In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...
that is derived from lambda calculus
Lambda calculus (also written as ''λ''-calculus) is a formal system in mathematical logic for expressing computation based on function abstraction and application using variable binding and substitution. It is a universal model of computation t ...
.
Logic Gate Matrices
''Logic Gate Matrices'' (a.k.a. LGM), developed by Brian McConnell, describes a universal virtual machine
In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...
that is constructed by connecting coordinates in an n-dimensional space via mathematics and logic operations, for example: (1,0,0) <-- (OR (0,0,1) (0,0,2)). Using this method, one may describe an arbitrarily complex computing substrate as well as the instructions to be executed on it.
Natural language messages
This research focuses on the event that we receive a signal or message that is either not directed at us (eavesdropping) or one that is in its natural communicative form. To tackle this difficult, but probable scenario, methods are being developed that will detect if a signal has structure indicative of an intelligent source, categorize the type of structure detected, and then decipher its content, from its physical level encoding and patterns to the parts-of-speech that encode internal and external ontologies.
Primarily, this structure modeling focuses on the search for generic human and inter-species language universals to devise computational methods by which language may be discriminated from non-language, and core structural syntactic elements of unknown languages may be detected. Aims of this research include contributing to the understanding of language structure and the detection of intelligent language-like features in signals, in order to aid the search for extraterrestrial intelligence.
The problem goal is therefore to separate language from non-language without dialogue, and learn something about the structure of language in the passing. The language may not be human (animals, aliens, computers, etc.), the perceptual space may be unknown, and human language structure cannot be presumed, but must begin somewhere. The language signal should be approached from a naive viewpoint, increasing ignorance and assuming as little as possible.
If a sequence can be tokenized, that is, separated into "words", an unknown human language may be distinguished from many other data sequences by the frequency distribution of the tokens. Human languages conform to a Zipfian distribution, while many (but not all) other data sequences do not. It has been proposed that an alien language also might conform to such a distribution. When displayed in a log-log graph of frequency vs. rank, this distribution would appear as a somewhat straight line with a slope of approximately -1. SETI
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
scientist Laurance Doyle explains that the slope of a line that represents individual tokens in a stream of tokens may indicate whether the stream contains linguistic or other structured content. If the line angles at 45°, the stream contains such content. If the line is flat, it does not.
CETI researchers
*Frank Drake
Frank Donald Drake (May 28, 1930 – September 2, 2022) was an American astrophysicist and astrobiologist.
He began his career as a radio astronomer, studying the planets of the Solar System and later pulsars. Drake expanded his interests ...
(SETI Institute): SETI
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
pioneer, composed the Arecibo message
The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 in 1974. It was meant as a demonstration of human technological achievement, rather than ...
.
*Dr John Elliott: research into developing strategies, which are based on receiving a 'natural' language message, that look at developing algorithms to detect if an ET signal has intelligent-like structure and if so, then how to decipher its content. Author of many papers in this area and a contributor to SETI's book on interstellar communication. Other contributions include message design and construction; member of: International Academy of Astronautics, SETI Permanent Study Group; International Task Group for the Post-detection identification of unknown radio signals.
*Laurence Doyle (SETI Institute): studies animal communication, and has developed statistical measures of complexity in animal utterances as well as human language.
*Stephane Dumas: developed ''Cosmic Call'' messages, as well as a general technique for generating 2-D symbols that remain recognizable even if corrupted by noise.
*Yvan Dutil
Yvan Dutil, born April 6, 1970, is a Canadian astrophysicist. He is a member of the Bioastronomy Commission of the International Astronomical Union and of the International Academy of Astronautics's Permanent Committee on the Search for Extra ...
: developed ''Cosmic Call'' messages with Stephane Dumas.
*Paul Fitzpatrick (MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
): developed ''CosmicOS'' system based on lambda calculus
Lambda calculus (also written as ''λ''-calculus) is a formal system in mathematical logic for expressing computation based on function abstraction and application using variable binding and substitution. It is a universal model of computation t ...
*Brian McConnell: developed framework for algorithmic communication systems (ACETI) from 2000 to 2002.
*Marvin Minsky
Marvin Lee Minsky (August 9, 1927 – January 24, 2016) was an American cognitive and computer scientist concerned largely with research of artificial intelligence (AI), co-founder of the Massachusetts Institute of Technology's AI laboratory, a ...
(MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
AI researcher): Believes that aliens may think similarly to humans because of shared constraints, permitting communication. First proposed the idea of including algorithms within an interstellar message.
*Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ...
: co-authored the Arecibo message and was heavily involved in SETI
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
throughout his life.
* Douglas Vakoch ( METI): editor of ''Archaeology, Anthropology, and Interstellar Communication
''Archaeology, Anthropology, and Interstellar Communication'' is a 2014 collection of essays edited by Douglas Vakoch and published by NASA. The book is focused on the role that the humanities and social sciences, in particular anthropology and ...
'', a 2014 essay collection on CETI.
* Alexander Zaitsev (IRE, Russia): composed '' Teen Age Message'' with Boris Pshenichner, Lev Gindilis, Lilia Filippova, et al., composed ''Bilingual Image Glossary'' for ''Cosmic Call 2003 Message'', Scientific Manager of transmitting from Evpatoria Planetary Radar the Cosmic Call
Cosmic commonly refers to:
* The cosmos, a concept of the universe
Cosmic may also refer to:
Media
* ''Cosmic'' (album), an album by Bazzi
* Afro/Cosmic music
* "Cosmic", a song by Kylie Minogue from the album '' X''
* CosM.i.C, a member of ...
1999, the Teen Age Message 2001, and the Cosmic Call
Cosmic commonly refers to:
* The cosmos, a concept of the universe
Cosmic may also refer to:
Media
* ''Cosmic'' (album), an album by Bazzi
* Afro/Cosmic music
* "Cosmic", a song by Kylie Minogue from the album '' X''
* CosM.i.C, a member of ...
2003, Scientific consultant for A Message From Earth project.
*Michael W. Busch: ( Lone Signal) created the binary encoding system for the ongoing Lone Signal hailing message.
*Jacob Haqq Misra: ( Lone Signal) is the chief science officer for the ongoing Lone Signal active SETI project.
Interspecies communication
Some researchers have concluded that in order to communicate with extraterrestrial species, humanity must first try to communicate with Earth's intelligent animal species. John C. Lilly worked with interspecies communication
Interspecies communication is communication between different species of animals, plants, or microorganisms.
Mutualism
Cooperative interspecies communication implies sharing and understanding information between two or more species that work tow ...
by teaching dolphins English (successful with rhythms, not with understandability, given their different mouth/blowhole shapes). He practiced various disciplines of spirituality and also ingested psychedelic drug
Psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness (known as psychedelic experiences or "trips").Pollan, Michael (2018). ''How to Change Your Mind: What the New Science ...
s such as LSD
Lysergic acid diethylamide (LSD), also known colloquially as acid, is a potent psychedelic drug. Effects typically include intensified thoughts, emotions, and sensory perception. At sufficiently high dosages LSD manifests primarily mental, vi ...
and (later) ketamine
Ketamine is a dissociative anesthetic used medically for induction and maintenance of anesthesia. It is also used as a recreational drug. It is one of the safest anesthetics, as, in contrast with opiates, ether, and propofol, it suppresses ...
in the company of dolphins. He tried to determine whether he could communicate non-verbally with dolphins, and also tried to determine if some extraterrestrial radio signals are intelligent communications. Similarly, Laurance Doyle, Robert Freitas
Robert A. Freitas Jr. (born 1952) is an American nanotechnologist.
Career
In 1974, Freitas earned a bachelor's degree in both physics and psychology from Harvey Mudd College, and in 1978, he received a Juris Doctor (J.D.) degree from Santa Clara ...
and Brenda McCowan compare the complexity of cetacean and human languages to help determine whether a specific signal from space is complex enough to represent a message that needs to be decoded.
See also
* Active SETI
* Animal language
Animal languages are forms of non-human animal communication that show similarities to human language. Animals communicate through a variety of signs, such as sounds or movements. Signing among animals may be considered complex enough to be a form ...
* Astrolinguistics
* Human–animal communication
Human–animal communication is the communication observed between humans and other animals, ranging from non-verbal cues and vocalizations to the use of language.
Some human–animal communication may be observed in casual circumstances, such a ...
* Nexus for Exoplanet System Science
The Nexus for Exoplanet System Science (NExSS) initiative is a National Aeronautics and Space Administration (NASA) virtual institute designed to foster interdisciplinary collaboration in the search for Extraterrestrial life, life on exoplanets. ...
* Pioneer plaque
The Pioneer plaques are a pair of gold-anodized aluminum plaques that were placed on board the 1972 ''Pioneer 10'' and 1973 ''Pioneer 11'' spacecraft, featuring a pictorial message, in case either ''Pioneer 10'' or ''11'' is intercepted by inte ...
* SETIcon
* Time capsule
A time capsule is a historic cache of goods or information, usually intended as a deliberate method of communication with future people, and to help future archaeologists, anthropologists, or historians. The preservation of holy relics date ...
* Waterhole (radio)
The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum between 1420 and 1662 megahertz, corresponding to wavelengths of 21 and 18 centimeters, respectively. It is a popular observing frequency used by radio t ...
* Wow! Signal
References
Further reading
Braastad, Richard, The Extraterrestrial Sermons
* Cattermole, P., & Moore, P. (1997). ''Atlas of Venus''. Cambridge University Press.
Dumas, Stepane. The 1999 and 2003 messages explained
* Dutil, Dumas,
EllaZ Systems
* Ley, Willy. ''Rockets, Missiles, and Space Travel'' (revised). New York: The Viking Press (1958)
* McConnell, Brian S. 2001 ''Beyond Contact: A Guide to SETI and Communicating with Alien Civilizations''. O'Reilly, Cambridge, Massachusetts
* McConnell, Brian S. 2002 Algorithmic Communication with ETI & Mixed Media Message Composition
* Minsky, Marvin, talk given at Communication With Extraterrestrial Intelligence (CETI), Proceedings of a conference held at the Byurakan Astrophysical Observatory, Yerevan, USSR, 5–11 September 1971. Edited by Carl Sagan. Cambridge, Massachusetts: The Massachusetts Institute of Technology, 1973. p. ix
* Morrison, P. "Interstellar Communication", ''Bulletin of the Philosophical Society of Washington
Founded in 1871, the Philosophical Society of Washington is the oldest scientific society in Washington, D.C. It continues today as PSW Science.
Since 1887, the Society has met regularly in the assembly hall of the Cosmos Club. In the Club's p ...
'', 16, 78 (1962). Reprinted in A. G. W. Cameron, ed., Interstellar Communication.
* Oberhaus, D. (2019) Extraterrestrial Languages. MIT Press.
Team Encounter, Cosmic Call, 2003
Vakoch, D. A. (Ed.). (2011) - Communication with Extraterrestrial Intelligence
New York: SUNY Press.
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