Post by Andrei Tchentchik on Apr 5, 2019 12:59:58 GMT 2
(.#165).- Seti: search for an extraterrestrial life.
Seti: search for an extraterrestrial life.
Elisabeth Piotelat
Engineer of CNRS studies
Posted on 07/11/2010 - Modified on 08/09/2016
Does an extraterrestrial life exist in the universe? This question has always haunted the mind of man. The Seti program, dedicated to the search for extraterrestrial intelligence, has been trying to find answers for more than 50 years.
Philosophers have long wondered about our place in the universe. Are we alone?
The Milky Way. © Ranfei - CC BY-SA 4.0
Far from all light, if you look up on a beautiful night without clouds, you can see thousands of stars. Are there also planets around? Satellites like Corot regularly bring us amazing information. But after ? Can there be vegetation, bacteria, animals, intelligent beings around all these bright spots?
The Seti program listens to the sky in search of extraterrestrial intelligence. © Élisabeth Piotelat
It's only been a little over 50 years since our technology allows us to look for an answer. These projects of listening of the sky are grouped under the acronym Seti for Search for Extra-Terrestrial Intelligence, or in French: search for extraterrestrial intelligence. Since the first listenings in 1960, there has always been, somewhere in the world, an active project.
If the reception of an intelligent signal of extraterrestrial origin still belongs to science-fiction, our technology has experienced an incredible evolution in half a century, or rather for a tenth of a second, if we use the cosmic calendar. A brief trip to the past allows us to keep hope: the quest is just beginning.
In this file, discover the beginnings of the Seti program in 1960, the advances made in the search for extraterrestrial intelligence and the conclusions that have been given.
On April 8, 1960, the Green Bank radio telescope began a new type of observation. In the direction of the stars Tau Ceti and Epsilon Eridani, he looks for artificial signals of cosmic origin. This project, named Ozma, originally from Seti, will represent nearly 200 hours of listening, on a single channel at the frequency of 1.420 MHz ...
Seti plays. © Sdecoretn Shutterstock
Ozma Project
The idea came from a young researcher, Franck Drake. His doctorate in his pocket, he wanted to realize one of his childhood dreams, answering the question: "Are we alone in the universe? "
The director of the observatory, Otto Sturve, supported him but asked him not to advertise the creation of his project Ozma, the origin of Seti, to avoid interference with the press. He bit his fingers when, in September 1959, the journal Nature published the article by Cocconi and Morrison, who advocated listening to the sky at the frequency of hydrogen, that is to say ie 1.420 MHz.
Why 1,420 MHz ?
Hydrogen is the most common element in the universe. We can imagine that a possible civilization will have discovered its radiation at 1.420 MHz and will have built the instruments to detect it. However, on Earth, this frequency is reserved for radio astronomy and can not be used to send radio signals. Some advise to listen right next, even in the cosmic water hole.
What is the cosmic water hole?
The diagram below shows the radio waves seen from the Earth. Between galactic noise in the low frequencies and the absorption due to the atmosphere in the high frequencies, there remains only a small window between 1 and 10 GHz.
The water hole. © Seti League
Since the frequency band between that of hydrogen (H) and that of the OH radical is visible from all over the cosmos, it has been nicknamed "cosmic waterhole" by Barney Oliver, one of the pioneers of the Seti research.
Barney Oliver said, "Where do we meet our neighbors? At the waterhole, where all the species meet! "
50 years on the cosmic scale
It is sometimes difficult to evaluate the durations at the cosmic scale. For us, 50 years may seem old but astronomically it's nothing.
Cosmic calendar. © PublicDomainPictures - CCO
Some dates of the cosmic calendar. © DR
It is difficult to realize the scales of cosmic time. The Big Bang, for example, took place 13.8 billion years ago. But what do 1 billion years represent?
The cosmic calendar
If we were on December 31 at midnight and the Big Bang took place just a year ago, at 0 am on January 1, the Sun would have been born on September 14, Homo sapiens would have appeared on December 31 at 22 h 30 and the project Ozma would have started a little more than a tenth of a second. It is not long since we have been scanning the sky for intelligent living.
At the scale of this cosmic calendar, the phone may have ranged 10 minutes, 10 days or 2 months. We were not able to answer them.
SETI: Evolution of listening techniques
Our technology has evolved enormously in over 50 years. The individual computer found in the cottages is more powerful than the one used by Drake. Our radio communications have become more complex and more numerous.
Are we alone in the universe ? © Geralt – CCO
Simplified diagram of a station Seti. © Seti League
Yet an engineer from the beginning of the last century transported to our world with his receiver would not pick up any radio waves, because he does not know the frequency modulation (FM).
In over 50 years, there has almost always been, somewhere in the world, a Seti type of listening. To this end, there are nearly 90 projects.
Hardware for everyone
From the Arecibo radio telescope to the small antenna, the reception principle is the same. The power will depend on the size of the antenna, whether or not it can target different parts of the sky, but especially the receiver.
In 1993, two radio amateurs founded a non-profit association, the Seti League. Very quickly, a hundred stations were born around the world as part of the Argus project. Many are in the United States, where there were large satellite reception antennas.
Five million participants for SETI @ HOME
By 1960, science fiction writers were more likely to imagine huge computers than multiple connected personal computers.
In 1999, Internet users were involved in the SETI @ HOME project. The initiative, which was to last two years, is still active. More than five million participants in 226 different countries generate nearly 200 Teraflops / s.
BOINC Helps Extend Seti Research
The software has undergone significant changes. Today, BOINC, which is a major spin-off of the quest for extraterrestrial intelligence, allows Internet users to contribute to multiple projects, for example the fight against malaria.
Even though no extraterrestrial signal has been found in more than 50 years, Seti will no doubt have led to advances in other disciplines.
The BOINC screen calculating data for SETI @ HOME. © DR
Number of channels: from 1 to 2G
If amateurs can contribute to the analysis of the signals, it is thanks to the law of Moore. The engineer predicted in 1975 that the number of PCB transistors would double every two years.
An important feature of Seti projects is the number of channels they use. Compared to a radio, Drake listened to only one station at a time in 1960 while in 2009, Serendip V could listen to twice 1012 (or 2G).
Moore's law therefore applies more or less to the evolution of the number of channels used by astronomers in Seti projects.
Multiplication of antennas
Inaugurated in 1963, the Arecibo radio telescope has an antenna 305 m in diameter. The decimetric radio telescope of Nançay was inaugurated in 1965 by Charles de Gaulle. The flat reflector consists of 10 independent panels 20 m wide and 40 high. While the size of antennas was an important issue at the beginning of radioastronomy, this is no longer the case today.
In 1971, a summer school was organized by NASA on the theme of the search for extraterrestrial life. It is called Cyclops project. Its purpose is to determine what will be needed in terms of hardware, personnel, time and budget to attempt to detect intelligent alien life outside the Solar System.
The Cyclops project report. © DR
In 1972, Project Cyclops, a Design Study of a system for detecting Extreterrestrial Intelligent Life, a voluminous technical report describing an interferometer is published by NASA. Ten thousand copies are distributed quickly. The views of artists show a large number of antennas, which frightened the politicians. However, the conclusions stipulated that we could start with a small network and extend it as we go along.
In 1997, the Seti Institute launched a series of workshops to define the goals of the next 20 years. The final report, Seti 2020, recommends the construction of a one hectare telescope (1HT: One Hectar Telescop).
[img src="
" alt=" "]
Seti 2020, the report of the Seti Institute. © DR
In 2001, the project received funding from Paul Allen, one of the founders of Microsoft. The 1HT was called Ata for Allen Telescope Array. The goal is to have 350 antennas of 6.1 m in diameter each.
Currently, only 42 antennas are operational. For the first time, a radio telescope is entirely devoted to Seti 24 hours a day, 7 days a week.
New strategies
We can see that the technical progress is immense as far as the reception of radio waves is concerned. However, the quest for extraterrestrial intelligence has explored new avenues since its inception. Numerous acronyms have appeared, such as Oseti for Optical Seti, which brings together all optical research.
In 2010, we celebrated the 50th anniversary of the discovery of the laser. In 1961, Nobel laureate Charles Towned suggested the search for extraterrestrial laser signals in an article co-authored with Dr. Shalow.
One of the pioneers is Stuart Kingsley, a member of the Seti League, who set up an observatory in Columbus, USA, before moving to Bournemouth in England.
The Planetary Society funded the Optical Seti Telescope at the Oak Ridge Observatory at Harvard. It was inaugurated on April 11, 2006. In January 2007, the telescope had covered the entire visible sky with 200 clear nights.
Ata telescope : You still have not received anything ?
In search of a life elsewhere than on Earth, the Ata telescope is on the lookout for the slightest sound activity in space. Specially dedicated to the Seti program, it has still not received a signal. But it is, perhaps, only a question of time ...
The mysterious universe. © WikiImages – CCO
The signal Wow! received in 1977. © The Ohio State University Radio Observatory and the North American AstroPhysical Observatory (Naapo), DP
The Ata telescope in the service of Seti
Even if 50 years represent half of a human life, on the cosmic scale, it is not much. Although there has almost always been a radio telescope listening somewhere in the world, since the Ozma project, we have not long ago a telescope dedicated to Seti, the Allen Telescope Array (Ata ).
Seti research adopts a scientific approach and implements protocols that impose verifications. We can not shout "We are not alone in the universe! Without bringing any extraordinary proof. For example, some projects selected candidate signals based on certain criteria. These are not proofs of the existence of intelligent extraterrestrial life until they are repeated until such time as no other explanation is possible.
The Big Ear radio telescope perceives a sound
On August 15, 1977, a signal was received by a radio telescope named Big Ear in Ohio. The service operator wrote "Wow! Next to the paper exit. Many assumptions about its origin have been made but none is confirmed. The only certainty is that if we do not seek, we will not find anything. We must persevere. Maybe by 2060 ...
To learn more about the Seti program, browse through the sources below.
Do other forms of life exist? © Geralt – CCO
The sites dedicated to Seti :
the Seti League:
French version:
the BOINC download: "SETI @ HOME"
the Francophone Alliance: www.boinc-af.org.
Online information only in English:
Seti Institute:
Big Ear (Wow!): Www.bigear.org/default.htm.
Published articles :
SETI @ SF in Aliens of science fiction: www.moutons-electriques.fr/livre.php?p=intro&n=67;
A chronology of Seti in Astronomy, volume 121: www2.saf-lastronomie.com/lastro/last0706.htm.
F I N .
Seti: search for an extraterrestrial life.
Elisabeth Piotelat
Engineer of CNRS studies
Posted on 07/11/2010 - Modified on 08/09/2016
Does an extraterrestrial life exist in the universe? This question has always haunted the mind of man. The Seti program, dedicated to the search for extraterrestrial intelligence, has been trying to find answers for more than 50 years.
Philosophers have long wondered about our place in the universe. Are we alone?
The Milky Way. © Ranfei - CC BY-SA 4.0
Far from all light, if you look up on a beautiful night without clouds, you can see thousands of stars. Are there also planets around? Satellites like Corot regularly bring us amazing information. But after ? Can there be vegetation, bacteria, animals, intelligent beings around all these bright spots?
The Seti program listens to the sky in search of extraterrestrial intelligence. © Élisabeth Piotelat
It's only been a little over 50 years since our technology allows us to look for an answer. These projects of listening of the sky are grouped under the acronym Seti for Search for Extra-Terrestrial Intelligence, or in French: search for extraterrestrial intelligence. Since the first listenings in 1960, there has always been, somewhere in the world, an active project.
If the reception of an intelligent signal of extraterrestrial origin still belongs to science-fiction, our technology has experienced an incredible evolution in half a century, or rather for a tenth of a second, if we use the cosmic calendar. A brief trip to the past allows us to keep hope: the quest is just beginning.
In this file, discover the beginnings of the Seti program in 1960, the advances made in the search for extraterrestrial intelligence and the conclusions that have been given.
On April 8, 1960, the Green Bank radio telescope began a new type of observation. In the direction of the stars Tau Ceti and Epsilon Eridani, he looks for artificial signals of cosmic origin. This project, named Ozma, originally from Seti, will represent nearly 200 hours of listening, on a single channel at the frequency of 1.420 MHz ...
Seti plays. © Sdecoretn Shutterstock
Ozma Project
The idea came from a young researcher, Franck Drake. His doctorate in his pocket, he wanted to realize one of his childhood dreams, answering the question: "Are we alone in the universe? "
The director of the observatory, Otto Sturve, supported him but asked him not to advertise the creation of his project Ozma, the origin of Seti, to avoid interference with the press. He bit his fingers when, in September 1959, the journal Nature published the article by Cocconi and Morrison, who advocated listening to the sky at the frequency of hydrogen, that is to say ie 1.420 MHz.
Why 1,420 MHz ?
Hydrogen is the most common element in the universe. We can imagine that a possible civilization will have discovered its radiation at 1.420 MHz and will have built the instruments to detect it. However, on Earth, this frequency is reserved for radio astronomy and can not be used to send radio signals. Some advise to listen right next, even in the cosmic water hole.
What is the cosmic water hole?
The diagram below shows the radio waves seen from the Earth. Between galactic noise in the low frequencies and the absorption due to the atmosphere in the high frequencies, there remains only a small window between 1 and 10 GHz.
The water hole. © Seti League
Since the frequency band between that of hydrogen (H) and that of the OH radical is visible from all over the cosmos, it has been nicknamed "cosmic waterhole" by Barney Oliver, one of the pioneers of the Seti research.
Barney Oliver said, "Where do we meet our neighbors? At the waterhole, where all the species meet! "
50 years on the cosmic scale
It is sometimes difficult to evaluate the durations at the cosmic scale. For us, 50 years may seem old but astronomically it's nothing.
Cosmic calendar. © PublicDomainPictures - CCO
Some dates of the cosmic calendar. © DR
It is difficult to realize the scales of cosmic time. The Big Bang, for example, took place 13.8 billion years ago. But what do 1 billion years represent?
The cosmic calendar
If we were on December 31 at midnight and the Big Bang took place just a year ago, at 0 am on January 1, the Sun would have been born on September 14, Homo sapiens would have appeared on December 31 at 22 h 30 and the project Ozma would have started a little more than a tenth of a second. It is not long since we have been scanning the sky for intelligent living.
At the scale of this cosmic calendar, the phone may have ranged 10 minutes, 10 days or 2 months. We were not able to answer them.
SETI: Evolution of listening techniques
Our technology has evolved enormously in over 50 years. The individual computer found in the cottages is more powerful than the one used by Drake. Our radio communications have become more complex and more numerous.
Are we alone in the universe ? © Geralt – CCO
Simplified diagram of a station Seti. © Seti League
Yet an engineer from the beginning of the last century transported to our world with his receiver would not pick up any radio waves, because he does not know the frequency modulation (FM).
In over 50 years, there has almost always been, somewhere in the world, a Seti type of listening. To this end, there are nearly 90 projects.
Hardware for everyone
From the Arecibo radio telescope to the small antenna, the reception principle is the same. The power will depend on the size of the antenna, whether or not it can target different parts of the sky, but especially the receiver.
In 1993, two radio amateurs founded a non-profit association, the Seti League. Very quickly, a hundred stations were born around the world as part of the Argus project. Many are in the United States, where there were large satellite reception antennas.
Five million participants for SETI @ HOME
By 1960, science fiction writers were more likely to imagine huge computers than multiple connected personal computers.
In 1999, Internet users were involved in the SETI @ HOME project. The initiative, which was to last two years, is still active. More than five million participants in 226 different countries generate nearly 200 Teraflops / s.
BOINC Helps Extend Seti Research
The software has undergone significant changes. Today, BOINC, which is a major spin-off of the quest for extraterrestrial intelligence, allows Internet users to contribute to multiple projects, for example the fight against malaria.
Even though no extraterrestrial signal has been found in more than 50 years, Seti will no doubt have led to advances in other disciplines.
The BOINC screen calculating data for SETI @ HOME. © DR
Number of channels: from 1 to 2G
If amateurs can contribute to the analysis of the signals, it is thanks to the law of Moore. The engineer predicted in 1975 that the number of PCB transistors would double every two years.
An important feature of Seti projects is the number of channels they use. Compared to a radio, Drake listened to only one station at a time in 1960 while in 2009, Serendip V could listen to twice 1012 (or 2G).
Moore's law therefore applies more or less to the evolution of the number of channels used by astronomers in Seti projects.
Multiplication of antennas
Inaugurated in 1963, the Arecibo radio telescope has an antenna 305 m in diameter. The decimetric radio telescope of Nançay was inaugurated in 1965 by Charles de Gaulle. The flat reflector consists of 10 independent panels 20 m wide and 40 high. While the size of antennas was an important issue at the beginning of radioastronomy, this is no longer the case today.
In 1971, a summer school was organized by NASA on the theme of the search for extraterrestrial life. It is called Cyclops project. Its purpose is to determine what will be needed in terms of hardware, personnel, time and budget to attempt to detect intelligent alien life outside the Solar System.
The Cyclops project report. © DR
In 1972, Project Cyclops, a Design Study of a system for detecting Extreterrestrial Intelligent Life, a voluminous technical report describing an interferometer is published by NASA. Ten thousand copies are distributed quickly. The views of artists show a large number of antennas, which frightened the politicians. However, the conclusions stipulated that we could start with a small network and extend it as we go along.
In 1997, the Seti Institute launched a series of workshops to define the goals of the next 20 years. The final report, Seti 2020, recommends the construction of a one hectare telescope (1HT: One Hectar Telescop).
[img src="
" alt=" "]Seti 2020, the report of the Seti Institute. © DR
In 2001, the project received funding from Paul Allen, one of the founders of Microsoft. The 1HT was called Ata for Allen Telescope Array. The goal is to have 350 antennas of 6.1 m in diameter each.
Currently, only 42 antennas are operational. For the first time, a radio telescope is entirely devoted to Seti 24 hours a day, 7 days a week.
New strategies
We can see that the technical progress is immense as far as the reception of radio waves is concerned. However, the quest for extraterrestrial intelligence has explored new avenues since its inception. Numerous acronyms have appeared, such as Oseti for Optical Seti, which brings together all optical research.
In 2010, we celebrated the 50th anniversary of the discovery of the laser. In 1961, Nobel laureate Charles Towned suggested the search for extraterrestrial laser signals in an article co-authored with Dr. Shalow.
One of the pioneers is Stuart Kingsley, a member of the Seti League, who set up an observatory in Columbus, USA, before moving to Bournemouth in England.
The Planetary Society funded the Optical Seti Telescope at the Oak Ridge Observatory at Harvard. It was inaugurated on April 11, 2006. In January 2007, the telescope had covered the entire visible sky with 200 clear nights.
Ata telescope : You still have not received anything ?
In search of a life elsewhere than on Earth, the Ata telescope is on the lookout for the slightest sound activity in space. Specially dedicated to the Seti program, it has still not received a signal. But it is, perhaps, only a question of time ...
The mysterious universe. © WikiImages – CCO
The signal Wow! received in 1977. © The Ohio State University Radio Observatory and the North American AstroPhysical Observatory (Naapo), DP
The Ata telescope in the service of Seti
Even if 50 years represent half of a human life, on the cosmic scale, it is not much. Although there has almost always been a radio telescope listening somewhere in the world, since the Ozma project, we have not long ago a telescope dedicated to Seti, the Allen Telescope Array (Ata ).
Seti research adopts a scientific approach and implements protocols that impose verifications. We can not shout "We are not alone in the universe! Without bringing any extraordinary proof. For example, some projects selected candidate signals based on certain criteria. These are not proofs of the existence of intelligent extraterrestrial life until they are repeated until such time as no other explanation is possible.
The Big Ear radio telescope perceives a sound
On August 15, 1977, a signal was received by a radio telescope named Big Ear in Ohio. The service operator wrote "Wow! Next to the paper exit. Many assumptions about its origin have been made but none is confirmed. The only certainty is that if we do not seek, we will not find anything. We must persevere. Maybe by 2060 ...
To learn more about the Seti program, browse through the sources below.
Do other forms of life exist? © Geralt – CCO
The sites dedicated to Seti :
the Seti League:
French version:
the BOINC download: "SETI @ HOME"
the Francophone Alliance: www.boinc-af.org.
Online information only in English:
Seti Institute:
Big Ear (Wow!): Www.bigear.org/default.htm.
Published articles :
SETI @ SF in Aliens of science fiction: www.moutons-electriques.fr/livre.php?p=intro&n=67;
A chronology of Seti in Astronomy, volume 121: www2.saf-lastronomie.com/lastro/last0706.htm.
F I N .
