Glossary term: Extraterrestrial Intelligence
Description: Extraterrestrial intelligence refers to the possible existence of intelligent entities other than those on Earth.
Searches for extraterrestrial intelligence have included looking for radio or other signals, but much current research is centered on determining whether the conditions for intelligent life are present elsewhere. Going by the available evidence, the necessary conditions for the emergence of life on Earth – a solid planet, at a distance from its star where liquid water can exist on the planet's surface, atoms like carbon and oxygen, and the conditions to form more complex molecules – should exist on numerous other planets within our Galaxy and beyond. It is not an unreasonable assumption that intelligent life might have arisen at least on some of those planets, although we have no solid basis for estimating the probability of that happening.
Some astronomers have used radio signals to search for putative messages as part of a Search for Extraterrestrial Intelligence (SETI). The speed of light as a fundamental physical limit means that interstellar journeys would take very long times, limiting the ability for us to come into direct contact with extraterrestrial intelligences.
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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
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In Other Languages
- Arabic: ذكاء من خارج الأرض
- German: Extraterrestrische Intelligenz
- French: Intelligence extraterrestre
- Italian: Intelligenza extraterrestre
- Brazilian Portuguese: Inteligência extraterrestre
- Simplified Chinese: 外星智能
- Traditional Chinese: 外星智能
Related Media
Arecibo Message
Caption: This image shows a representation of an interstellar radio message, known as the “Arecibo Message”. As part of this visualisation different parts are highlighted by different colors. It was sent on the 16th of November in 1974 from the Arecibo Telescope in Puerto Rico, at this time the largest radio telescope on Earth, on the 16th of November in 1974. Its destination was the globular cluster M13 in the constellation of Hercules. M13 is one of the brightest of its kind, contains about half a million stars and is located at a distance of approximately 25 000 light years. It was chosen as a target because of its dense stellar population, meaning the message would reach more stars and hopefully planets. Moreover, it is one of the nearer globular clusters available in the sky at the time and place when the message was sent.
The Arecibo Message was a symbolic event, intended to show that humans could broadcast a message to the stars. The message contains 1679 (chosen as it is the product of two prime numbers) bits of data which, when arrange in a two dimensional array, form the image shown here. It consists of seven parts which contain representations of DNA, a human, and information on the Earth and Solar System. The message content was designed by a group of scientists from Cornell University and the Arecibo Observatory.
Credit: Arne Nordmann (wikicommons user norro)
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License: CC-BY-SA-3.0 Creative Commons Attribution-ShareAlike 3.0 Unported icons
Pioneer Plaques
Caption: The Pioneer 10 and 11 spacecraft are the first human-made objects to leave the solar system and venture into interstellar space. To inform potentially intelligent species about our existence, they both carry small metal plaques identifying their time, place of origin and information about their builders. They provide the location of our solar system in the Milky Way by depicting the Solar System's position relative to 14 pulsars, with radiating lines that include information about their frequencies. A model of a hydrogen atom undergoing one particular atomic transition is depicted. The wavelength and frequency of this transition are used to express sizes and frequencies of the other items shown in the plaque. A more detailed view of Earth's position in the solar system, with the spacecraft's trajectory moving away from Earth, passing Mars and Jupiter is displayed at the bottom. The plaque also depicts a naked man and woman alongside the spacecraft to provide a sense of scale. The man’s hand is raised as a friendly gesture.
The 6-inch by 9-inch gold-anodized aluminum plate has the design engraved on it. It was attached to the support struts of the spacecraft's antenna to try to to protect it from erosion by any interstellar dust the spacecraft may encounter on its journey. Designed by Carl Sagan and Frank Drake, with artwork by Linda Salzman Sagan, these plaques are meant to communicate the origin of the spacecraft to any extraterrestrial life that might encounter them.
While Pioneer 10 is on a course towards the star Aldebaran in the Taurus constellation, which will take about two million years to reach, Pioneer 11 is heading in a different direction towards the constellation of Aquila. It will take approximately four million years to pass close to some of the constellation’s stars.
Credit: NASA Ames
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License: PD Public Domain icons
