Book contents
- Frontmatter
- Contents
- Preface to the Second Edition
- Preface to the First Edition
- 1 An Explanation for the Absence of Extraterrestrials on Earth
- 2 One Attempt to Find Where They Are: NASA's High Resolution Microwave Survey
- 3 An Examination of Claims that Extraterrestrial Visitors to Earth Are Being Observed
- 4 The Likelihood of Interstellar Colonization, and the Absence of Its Evidence
- 5 Pre-emption of the Galaxy by the First Advanced Civilization
- 6 Stellar Evolution: Motivation for Mass Interstellar Migrations
- 7 Interstellar Propulsion Systems
- 8 Interstellar Travel: A Review
- 9 Settlements in Space, and Interstellar Travel
- 10 Terraforming
- 11 Estimates of Expansion Timescales
- 12 A Search for Tritium Sources in Our Solar System May Reveal the Presence of Space Probes from Other Stellar Systems
- 13 Primordial Organic Cosmochemistry
- 14 Chance and the Origin of Life
- 15 The RNA World: Life before DNA and Protein
- 16 The Search for Extraterrestrial Intelligence
- 17 Alone in a Crowded Universe
- 18 Possible Forms of Life in Environments Very Different from the Earth
- 19 Cosmological SETI Frequency Standards
- 20 Galactic Chemical Evolution: Implications for the Existence of Habitable Planets
- 21 The Frequency of Planetary Systems in the Galaxy
- 22 Atmospheric Evolution, the Drake Equation and DNA: Sparse Life in an Infinite Universe
- About the Editors and Contributors
- Author Index
- Subject Index
12 - A Search for Tritium Sources in Our Solar System May Reveal the Presence of Space Probes from Other Stellar Systems
Published online by Cambridge University Press: 20 October 2009
- Frontmatter
- Contents
- Preface to the Second Edition
- Preface to the First Edition
- 1 An Explanation for the Absence of Extraterrestrials on Earth
- 2 One Attempt to Find Where They Are: NASA's High Resolution Microwave Survey
- 3 An Examination of Claims that Extraterrestrial Visitors to Earth Are Being Observed
- 4 The Likelihood of Interstellar Colonization, and the Absence of Its Evidence
- 5 Pre-emption of the Galaxy by the First Advanced Civilization
- 6 Stellar Evolution: Motivation for Mass Interstellar Migrations
- 7 Interstellar Propulsion Systems
- 8 Interstellar Travel: A Review
- 9 Settlements in Space, and Interstellar Travel
- 10 Terraforming
- 11 Estimates of Expansion Timescales
- 12 A Search for Tritium Sources in Our Solar System May Reveal the Presence of Space Probes from Other Stellar Systems
- 13 Primordial Organic Cosmochemistry
- 14 Chance and the Origin of Life
- 15 The RNA World: Life before DNA and Protein
- 16 The Search for Extraterrestrial Intelligence
- 17 Alone in a Crowded Universe
- 18 Possible Forms of Life in Environments Very Different from the Earth
- 19 Cosmological SETI Frequency Standards
- 20 Galactic Chemical Evolution: Implications for the Existence of Habitable Planets
- 21 The Frequency of Planetary Systems in the Galaxy
- 22 Atmospheric Evolution, the Drake Equation and DNA: Sparse Life in an Infinite Universe
- About the Editors and Contributors
- Author Index
- Subject Index
Summary
Introduction
The possibility that life, primitive or advanced, might exist in other parts of the universe has occupied the thoughts of scientists and laymen for thousands of years. One of the earliest was the statement by the ancient Greek philosopher Metrodorus of Chios around 400 b.c., who wrote in his book On Nature that: ‘It is unnatural in a large field to have only one shaft of wheat, and in the infinite Universe only one living world.’
In a.d. 1690 the famous Dutch physicist Christian Huygens wrote in his book Cosmotheoros that: ‘Barren planets, deprived of living creatures that speak most eloquently of their Divine Architect, are unreasonable, wasteful and uncharacteristic of God, who has a purpose for everything.’
In the nineteenth century, several proposals were made by different distinguished scientists. The most famous was mathematician Carl Friedrich Gauss, who proposed to establish contacts with advanced civilizations on other planets of our solar system, by planting a rectangular triangle with wheat in Siberia, with squares of pine trees at its three sides, to show that the Earth has intelligent beings that know the Pythagorean Theorem. None of these proposals, however, was implemented.
The modern era of the Search for Extra-Terrestrial Intelligence (SETI) started in 1959 with a paper to Nature by Cocconi and Morrison, which was followed soon after in the spring of 1960 by the first radio search by Frank Drake (Project OZMA), using the then new 85 foot radio telescope at the National Radio Astronomy Observatory in West Virginia.
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- ExtraterrestrialsWhere Are They?, pp. 103 - 107Publisher: Cambridge University PressPrint publication year: 1995
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