Communication with Extraterrestrial Intelligence

Communication with Extraterrestrial Intelligence

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Communication with extraterrestrial intelligence (CETI) is a branch of the search for extraterrestrial intelligence that focuses on composing and deciphering messages that could theoretically be understood by another technological civilization. The best-known CETI experiment was the 1974 Arecibo message
Arecibo message
The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...

 composed by Frank Drake
Frank Drake
Frank Donald Drake PhD is an American astronomer and astrophysicist. He is most notable as one of the pioneers in the search for extraterrestrial intelligence, including the founding of SETI, mounting the first observational attempts at detecting extraterrestrial communications in 1961 in Project...

 and Carl Sagan
Carl Sagan
Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...

. There is no single organization involved in CETI, such as the SETI Institute
SETI Institute
The SETI Institute is a not-for-profit organization whose mission is to “explore, understand and explain the origin, nature and prevalence of life in the universe”. SETI stands for the "search for extraterrestrial intelligence". One program is the use of both radio and optical telescopes to search...

, and the abbreviations CETI and SETI alone should not be taken as referring to any organization.

CETI research has focused on four broad areas: mathematical
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 languages, pictorial systems such as the Arecibo message, algorithmic communication systems (ACETI) and computational approaches to detecting and deciphering 'natural' language communication.

History


In the nineteenth century there were many books and articles about the possible inhabitants of other planets. Many people believed that intelligent beings might live on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

, Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

, and Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

; but since travel to other planets was not yet possible, some people suggested ways to signal the extraterrestrials even before radio was discovered.

Carl Friedrich Gauss
Carl Friedrich Gauss
Johann Carl Friedrich Gauss was a German mathematician and scientist who contributed significantly to many fields, including number theory, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics.Sometimes referred to as the Princeps mathematicorum...

 suggested that a giant triangle and three squares, the Pythagoras
Pythagoras
Pythagoras of Samos was an Ionian Greek philosopher, mathematician, and founder of the religious movement called Pythagoreanism. Most of the information about Pythagoras was written down centuries after he lived, so very little reliable information is known about him...

, could be drawn on the Siberian tundra. The outlines of the shapes would have been ten-mile wide strips of pine forest, the interiors could be rye or wheat.
Joseph Johann Littrow
Joseph Johann Littrow
Joseph Johann von Littrow was an Austrian astronomer. In 1837, he was ennobled with the title Joseph Johann Edler von Littrow. He was the father of Karl Ludwig Edler von Littrow and the mentor of the mathematician Nikolai Brashman...

 proposed using the Sahara as a 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 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
Franz von Gruithuisen
Baron Franz von Paula Gruithuisen was a Bavarian physician and astronomer. He taught medical students before becoming a professor of astronomy at the University of Munich in 1826....

 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
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

. Ashen light
Ashen light
Ashen light is a subtle glow that is seen from the night side of the planet Venus. This ashen light is said to be very similar to Earthshine on our moon, but not as distinguished in brightness. It was first sighted by the astronomer Giovanni Battista Riccioli on January 9, 1643, and has been...

 had been observed on 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
Pierre-Simon Laplace
Pierre-Simon, marquis de Laplace was a French mathematician and astronomer whose work was pivotal to the development of mathematical astronomy and statistics. He summarized and extended the work of his predecessors in his five volume Mécanique Céleste...

, which stated that the farthest planets from the sun are the oldest—therefore Mars was more likely to have advanced civilizations than Venus. It was evident that Venus was perpetually shrouded in clouds, so the Venusians probably would not be very good astronomers. Subsequent investigations focused on contacting Martians. In 1877 Giovanni Schiaparelli
Giovanni Schiaparelli
Giovanni Virginio Schiaparelli was an Italian astronomer and science historian. He studied at the University of Turin and Berlin Observatory. In 1859-1860 he worked in Pulkovo Observatory and then worked for over forty years at Brera 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 Mars enthusiasm.

The inventor Charles Cros
Charles Cros
Charles Cros was a French poet and inventor. He was born in Fabrezan, Aude, France, 35 km to the East of Carcassonne....

 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
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...

 mentioned many times during his career that he thought his inventions such as his Tesla coil
Tesla coil
A Tesla coil is a type of resonant transformer circuit invented by Nikola Tesla around 1891. It is used to produce high voltage, low current, high frequency alternating current electricity. Tesla coils produce higher current than the other source of high voltage discharges, electrostatic machines...

, used in the role of a "resonant receiver", could communicate with other planets and even observed repetitive signals of what he believed were Extraterrestrial radio communications coming from Venus or Mars in 1899. However, these "signals" turned out to be terrestrial radiation.

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.

When the Martian canals proved illusory, it seemed that humans were alone in the solar system.

Astraglossa


Published in 1953 by Lancelot Hogben
Lancelot Hogben
Lancelot Thomas Hogben FRS was a versatile British experimental zoologist and medical statistician. He is best known for developing Xenopus laevis as a model organism for biological research in his early career, attacking the eugenics movement in the middle of his career, and popularising books on...

 describes 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.

Lincos (Lingua cosmica)


Lincos
Lincos (language)
Lincos is an artificial language first described in 1960 by Dr. Hans Freudenthal in his book Lincos: Design of a Language for Cosmic Intercourse, Part 1. It is a language designed to be understandable by any possible intelligent extraterrestrial life form, for use in interstellar radio transmissions...

: Design of a Language for Cosmic Intercourse
, published in 1960 by Hans Freudenthal
Hans Freudenthal
Hans Freudenthal was a Dutch mathematician. He made substantial contributions to algebraic topology and also took an interest in literature, philosophy, history and mathematics education....

, expands upon Astraglossa to create a general-purpose language derived from basic mathematics and logic symbols. A new generation Lincos has been developed since 2000 by Alexander Ollongren, as a part of the more general Astrolinguistics.

Carl Sagan


The science fiction
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 novel Contact
Contact (novel)
Contact is a science fiction novel written by Carl Sagan and published in 1985. It deals with the theme of contact between humanity and a more technologically advanced, extraterrestrial life form. It ranked No. 7 on the 1985 U.S. bestseller list....

by Carl Sagan
Carl Sagan
Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...

 explored in some depth how a message might be constructed to allow communication with an alien civilization, using the prime number
Prime number
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example 5 is prime, as only 1 and 5 divide it, whereas 6 is composite, since it has the divisors 2...

s as a starting point, followed by various universal principles and facts of mathematics and science. Sagan also edited a non-fiction book on the subject, which has recently been updated.

Jack McDevitt


In his science fiction novel The Hercules Text
The Hercules Text
The Hercules Text is a 1986 science fiction novel by Jack McDevitt. It tells the story of a message of intelligent extraterrestrial origin received by SETI-scientists. The Hercules Text was nominated for the Philip K. Dick Award in 1986....

, Jack McDevitt
Jack McDevitt
Jack McDevitt is an American science fiction author whose novels frequently deal with attempts to make contact with alien races, and with archaeology or xenoarchaeology....

 describes an extraterrestrial message based on powers of 2
Power of two
In mathematics, a power of two means a number of the form 2n where n is an integer, i.e. the result of exponentiation with as base the number two and as exponent the integer n....

 as a starting point.

A language based on the fundamental facts of science


Published in 1992 by Carl Devito and Richard Oehrle, is similar in syntax to Astraglossa and Lincos but builds its vocabulary around known physical properties.

Pictorial messages


Pictorial communication systems seek to describe fundamental mathematical or physical concepts via simplified diagrams sent as bitmap
Bitmap
In computer graphics, a bitmap or pixmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits. Now, along with pixmap, it commonly refers to...

s. These messages assume that the recipient has similar visual capabilities (weak assumption) and can understand basic mathematics and geometry (strong assumption because both are prerequisites for building the optimal shape for a radio or optical telescope). A common critique of these systems is that they assume 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 could be interpreted as a weapon firing.

Pioneer probes


The two Pioneer plaque
Pioneer plaque
The Pioneer plaques are a pair of gold-anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 are intercepted by extraterrestrial life...

s were launched on Pioneer 10
Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...

 and Pioneer 11
Pioneer 11
Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...

 in 1972 and 1973, depicting the location of the Earth in the galaxy and the solar system, and the form of the human body.

Voyager probes


Launched in 1977, the Voyager
Voyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...

 probes carried two golden records
Voyager Golden Record
The Voyager Golden Records are phonograph records which were included aboard both Voyager spacecraft, which were launched in 1977. They contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for...

 that were inscribed with diagrams depicting the human form, our solar system and its location. Also included were recordings of pictures and sounds from Earth.

The Arecibo message


The Arecibo message
Arecibo message
The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...

, transmitted in 1974, was a 1679 pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....

 image with 73 rows and 23 columns. It shows the numbers one through ten, the atomic numbers of hydrogen, carbon, nitrogen, oxygen, and phosphorus, the formulas for the sugars and bases in the nucleotides of DNA, the number of nucleotides in DNA, the double helix structure of DNA, a figure of a human being and its height, the population of Earth, a diagram of our solar system, and an image of the Arecibo telescope with its diameter.

Cosmic Call messages


The Cosmic Call
Cosmic Call
Cosmic Call was the name of two interstellar radio messages that were sent from RT-70 in Yevpatoria in 1999 and 2003 to various nearby stars. The messages were designed with noise resistant format and characters....

messages consisted of a few digital sections - "Rosetta Stone", copy of Arecibo Message, Bilingual Image Glossary, the Braastad message, as well as text, audio, video and other image files submitted for transmission by everyday people around the world. The "Rosetta Stone" was composed by Stephane Dumas
Stéphane Dumas
Stéphane Louis André Dumas is a French basketball player who currently plays for Blancos de Rueda Valladolid.-Career:...

 and Yvan Dutil
Yvan Dutil
Yvan Dutil is a Canadian astrophysicist who, together with his colleague Stephane Dumas, in France: Stéphane Dumas, has created a noise-resistant coding system for messages aimed at communicating with extraterrestrial civilization. This system was used in the creation of messages beamed towards...

 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
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atom). The message is designed with noise resistant format and characters, which make it resistant to alteration by noise. These messages were transmitted in 1999 and 2003 from Evpatoria Planetary Radar under scientific guidance of Alexander L. Zaitsev. Richard Braastad coordinated the overall project.

Stars to which messages were sent, are the following:
Name Designation HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

Constellation Date sent Arrival date Message
16 Cyg A
16 Cygni
16 Cygni or 16 Cyg is a triple star system approximately 70 light-years away from Earth in the constellation of Cygnus. It consists of two Sun-like yellow dwarf stars, 16 Cygni A and 16 Cygni B, together with a red dwarf, 16 Cygni C...

HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 186408
Cygnus
Cygnus (constellation)
Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...

 
May 24, 1999 November 2069 Cosmic Call 1
15 Sge
15 Sagittae
15 Sagittae is a 6th magnitude star in the constellation Sagitta. In 2002, a brown dwarf, 15 Sge b, was discovered around 15 Sge.-15 Sagittae B:...

 
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 190406
Sagitta
Sagitta
Sagitta is a constellation. Its name is Latin for "arrow", and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations...

 
June 30, 1999 February 2057 Cosmic Call 1
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 178428
Sagitta
Sagitta
Sagitta is a constellation. Its name is Latin for "arrow", and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations...

 
June 30, 1999 October 2067 Cosmic Call 1
Gl 777
Gliese 777
Gliese 777, often abbreviated as Gl 777 or GJ 777, is a yellow subgiant approximately 52 light-years away in the constellation of Cygnus. The system is also a binary star system made up of two stars and possibly a third...

 
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 190360
Cygnus
Cygnus (constellation)
Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...

 
July 1, 1999 April 2051 Cosmic Call 1
Hip 4872 Cassiopeia
Cassiopeia (constellation)
Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...

 
July 6, 2003 April 2036 Cosmic Call 2
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 245409
Orion
Orion (constellation)
Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...

 
July 6, 2003 August 2040 Cosmic Call 2
55 Cnc
55 Cancri
55 Cancri , also cataloged Rho1 Cancri or abbreviated 55 Cnc, is a binary star approximately 41 light-years away from Earth in the constellation of Cancer...

 
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 75732
Cancer
Cancer (constellation)
Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...

 
July 6, 2003 May 2044 Cosmic Call 2
HD 10307
HD 10307
HD 10307 is a star similar to the sun in mass, temperature and metal content, situated about 41 light-years from Earth in the constellation Andromeda...

 
Andromeda
Andromeda (constellation)
Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...

 
July 6, 2003 September 2044 Cosmic Call 2
47 UMa
47 Ursae Majoris
47 Ursae Majoris is a solar analog, yellow dwarf star approximately 46 light-years away from Earth in the constellation of Ursa Major. , it has been confirmed that three Jupiter-like extrasolar planets orbit the star...

 
HD
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

 95128
Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...

 
July 6, 2003 May 2049 Cosmic Call 2

Teen-Age Message



The Teen-Age Message
Teen Age Message
The Teen Age Message was a METI message, transmitted from the Yevpatoria Planetary Radar to 6 nearby Sun-like stars during August–September 2001. Unlike the previous digital-only Messages, Arecibo-1974 and Cosmic Call 1, the TAM has complex, three-section structure with different forms of...

, composed by Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

n scientists (Zaitsev
Aleksandr Leonidovich Zaitsev
Aleksandr Leonidovich Zaitsev is a Russian and Soviet radio engineer and astronomer from Fryazino. He works on radar astronomy devices, near-Earth asteroid radar research, and SETI....

, Gindilis, Pshenichner, Filippova) and teens, was transmitted from the 70-m dish of Yevpatoria Deep Space Center to six Sun-like stars 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 and represents musical melodies, performed on the Theremin
Theremin
The theremin , originally known as the aetherphone/etherophone, thereminophone or termenvox/thereminvox is an early electronic musical instrument controlled without discernible physical contact from the player. It is named after its Russian inventor, Professor Léon Theremin, who patented the device...

. This electric musical instrument produces a quasi-monochromatic signal, which is easily detectable across interstellar distances. There were seven musical compositions in the 1st Theremin Concert for Aliens. It is important to understand that analog on-line transmission of the Theremin Concert in 14 minutes would take almost 50 hours in the case of transmission by the digital method, see 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.

Stars to which the message was sent are the following:
Name HD designation
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...

Constellation Date sent Arrival date
197076 Delphinus
Delphinus
Delphinus is a constellation in the northern sky, close to the celestial equator. Its name is Latin for dolphin. Delphinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains among the 88 modern constellations recognized by the International Astronomical...

 
August 29, 2001 February 2070
47 UMa
47 Ursae Majoris
47 Ursae Majoris is a solar analog, yellow dwarf star approximately 46 light-years away from Earth in the constellation of Ursa Major. , it has been confirmed that three Jupiter-like extrasolar planets orbit the star...

 
95128 Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...

 
September 3, 2001 July 2047
37 Gem  50692 Gemini
Gemini (constellation)
Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...

 
September 3, 2001 December 2057
126053 Virgo
Virgo (constellation)
Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...

 
September 3, 2001 January 2059
76151 Hydra
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...

 
September 4, 2001 May 2057
193664 Draco
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...

 
September 4, 2001 January 2059

Cosmic Call 2 (Cosmic Call 2003) message


The Cosmic Call
Cosmic Call
Cosmic Call was the name of two interstellar radio messages that were sent from RT-70 in Yevpatoria in 1999 and 2003 to various nearby stars. The messages were designed with noise resistant format and characters....

-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 mathematics and logic symbols that form the basis for a rudimentary programming language that the recipient can run on a virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...

. 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
Forward error correction
In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....

 (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
CosmicOS
CosmicOS is a self-contained message designed to be understood primarily by treating it as a computer program and executing it. It is inspired by Hans Freudenthal's Lincos and resembles the programming language Scheme in many ways....

, designed by Paul Fitzpatrick at MIT, describes a virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...

 that is derived from lambda calculus
Lambda calculus
In mathematical logic and computer science, lambda calculus, also written as λ-calculus, is a formal system for function definition, function application and recursion. The portion of lambda calculus relevant to computation is now called the untyped lambda calculus...

.

Logic Gate Matrices


Logic Gate Matrices (a.k.a. LGM), developed by Brian McConnell, describes a universal virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...

 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 can 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 / 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 first detect if a signal has intelligent-like structure, categorize the type of structure detected and then decipher its content: from its physical level encoding and patterns to the parts-of-speech, which 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 can be discriminated from non-language and core structural syntactic elements of unknown languages can be detected. Aims of this research include: contributing to the understanding of language structure and the detection of intelligent language-like features in signals, 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...), the perceptual space can be unknown, and we cannot assume human language structure but must begin somewhere. We need to approach the language signal from a naive viewpoint, in effect, increasing our ignorance and assuming as little as possible.

CETI researchers

  • Frank Drake
    Frank Drake
    Frank Donald Drake PhD is an American astronomer and astrophysicist. He is most notable as one of the pioneers in the search for extraterrestrial intelligence, including the founding of SETI, mounting the first observational attempts at detecting extraterrestrial communications in 1961 in Project...

     (SETI Institute): SETI
    SETI
    The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

     pioneer, composed the Arecibo message
    Arecibo message
    The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...

     with Carl Sagan
    Carl Sagan
    Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...

  • Dr John Elliott (SETI Research UK): 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
    Stéphane Dumas
    Stéphane Louis André Dumas is a French basketball player who currently plays for Blancos de Rueda Valladolid.-Career:...

    : 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
    Yvan Dutil is a Canadian astrophysicist who, together with his colleague Stephane Dumas, in France: Stéphane Dumas, has created a noise-resistant coding system for messages aimed at communicating with extraterrestrial civilization. This system was used in the creation of messages beamed towards...

    : developed Cosmic Call messages with Stephane Dumas.
  • Paul Fitzpatrick (MIT): developed CosmicOS system based on lambda calculus
    Lambda calculus
    In mathematical logic and computer science, lambda calculus, also written as λ-calculus, is a formal system for function definition, function application and recursion. The portion of lambda calculus relevant to computation is now called the untyped lambda calculus...

  • Brian McConnell: developed framework for algorithmic communication systems (ACETI) from 2000-2002.
  • Marvin Minsky
    Marvin Minsky
    Marvin Lee Minsky is an American cognitive scientist in the field of artificial intelligence , co-founder of Massachusetts Institute of Technology's AI laboratory, and author of several texts on AI and philosophy.-Biography:...

     (MIT AI
    Ai
    AI, A.I., Ai, or ai may refer to:- Computers :* Artificial intelligence, a branch of computer science* Ad impression, in online advertising* .ai, the ISO Internet 2-letter country code for Anguilla...

     researcher): first proposed the idea of including algorithms within an interstellar message.
  • Carl Sagan
    Carl Sagan
    Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...

     (deceased): co-authored the Arecibo message, and was heavily involved in SETI
    SETI
    The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

     throughout his life.
  • Douglas Vakoch (SETI Institute): studies CETI and has published numerous articles, as well as an upcoming book from MIT Press about interstellar communication.
  • Alexander Zaitsev
    Aleksandr Leonidovich Zaitsev
    Aleksandr Leonidovich Zaitsev is a Russian and Soviet radio engineer and astronomer from Fryazino. He works on radar astronomy devices, near-Earth asteroid radar research, and SETI....

     (IRE, Russia): composed Teen Age Message
    Teen Age Message
    The Teen Age Message was a METI message, transmitted from the Yevpatoria Planetary Radar to 6 nearby Sun-like stars during August–September 2001. Unlike the previous digital-only Messages, Arecibo-1974 and Cosmic Call 1, the TAM has complex, three-section structure with different forms of...

    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 Call
    Cosmic Call was the name of two interstellar radio messages that were sent from RT-70 in Yevpatoria in 1999 and 2003 to various nearby stars. The messages were designed with noise resistant format and characters....

     1999, the Teen Age Message
    Teen Age Message
    The Teen Age Message was a METI message, transmitted from the Yevpatoria Planetary Radar to 6 nearby Sun-like stars during August–September 2001. Unlike the previous digital-only Messages, Arecibo-1974 and Cosmic Call 1, the TAM has complex, three-section structure with different forms of...

     2001, and the Cosmic Call
    Cosmic Call
    Cosmic Call was the name of two interstellar radio messages that were sent from RT-70 in Yevpatoria in 1999 and 2003 to various nearby stars. The messages were designed with noise resistant format and characters....

     2003, Scientific consultant for A Message From Earth
    A Message From Earth
    A Message from Earth is a high-powered digital radio signal that was sent on 9 October 2008 towards Gliese 581 c, a large terrestrial extrasolar planet orbiting the red dwarf star Gliese 581. The signal is a digital time capsule containing 501 messages that were selected through a competition on...

     project.

See also

  • Active SETI
    Active SETI
    Active SETI is the attempt to send messages to intelligent aliens. Active SETI messages are usually in the form of radio signals. Physical messages like that of the Pioneer plaque may also be considered an active SETI message...

  • Time capsule
    Time capsule
    A time capsule is an historic cache of goods or information, usually intended as a method of communication with future people and to help future archaeologists, anthropologists, or historians...

  • Message in a bottle
    Message in a bottle
    A message in a bottle is a form of communication whereby a message is sealed in a container and released into the sea or ocean...

  • Pioneer plaque
    Pioneer plaque
    The Pioneer plaques are a pair of gold-anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 are intercepted by extraterrestrial life...

  • Waterhole (radio)
    Waterhole (radio)
    The waterhole, or water hole, refers to an especially quiet band of the electromagnetic spectrum between 1,420 and 1,666 megahertz, corresponding to wavelengths of 21 and 18 centimeters respectively. The term was coined by Bernard Oliver. The strongest hydroxyl radical spectral line radiates at 18...