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
2 - One Attempt to Find Where They Are: NASA's High Resolution Microwave Survey
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
Cocconi and Morrison (1959) closed their seminal paper on SETI with a statement that still well characterizes our current situation: ‘The probability of success is difficult to estimate, but if we never search the chance of success is zero.’ This chapter is a brief summary of how and why NASA has shaped the High Resolution Microwave Survey (HRMS), which it inaugurated on 12 October 1992. Some of the alternative search strategies that were considered are also noted, since these may well form the basis for the next generation of searches, should the HRMS fail to detect a signal.
Although this endeavor is often referred to as SETI (the Search for Extraterrestrial Intelligence), as it is implemented today, and into the foreseeable future, individual search projects are actually seeking evidence of extraterrestrial technology. Thus for scientists and engineers engaged in this exploration, a species' ability to technologically modify its local environment in ways that can be detected over interstellar distances has become a pragmatic substitute for the overly complex and convoluted definitions of ‘intelligence’ offered by researchers in other fields. Far in the future lies the promise of being able to detect indirect, but compelling, evidence of life itself on a distant planet. The coexistence of highly reactive gases (such as methane and oxygen) in the atmosphere of a planet, orbiting at an appropriate distance from its host star (so that liquid surface water might be possible) would suggest a continuous biological source at the base of that atmosphere.
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- ExtraterrestrialsWhere Are They?, pp. 9 - 19Publisher: Cambridge University PressPrint publication year: 1995