The Search for Extraterrestrial Intelligence, SETIPhilip Morrison, John Billingham, John Wolfe National Aeronautics and Space Administration, Scientific and Technical Information Office, 1977 - 276 páginas |
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Página 71
... bandwidth is larger than necessary and admits more noise per channel . Setting 7 = 1 / B we find B = v1 . Since i is proportional to v it follows that the optimum bandwidth increases as 12. The total receiver noise per channel is ...
... bandwidth is larger than necessary and admits more noise per channel . Setting 7 = 1 / B we find B = v1 . Since i is proportional to v it follows that the optimum bandwidth increases as 12. The total receiver noise per channel is ...
Página 72
... bandwidth index . One can of course put such beacons at the planet's poles or in long period orbits in space . Whatever is done to minimize Doppler and oscillator drifts , the frequency proportionality remains . The absolute achievable ...
... bandwidth index . One can of course put such beacons at the planet's poles or in long period orbits in space . Whatever is done to minimize Doppler and oscillator drifts , the frequency proportionality remains . The absolute achievable ...
Página 79
... bandwidth ) , and spectral line surveys ( 102 to 106 Hz bandwidth ) . Large bandwidths , absence of adequate spectral resolution , customary on - line instrumental data compaction , and absence of specific interest in the existence of ...
... bandwidth ) , and spectral line surveys ( 102 to 106 Hz bandwidth ) . Large bandwidths , absence of adequate spectral resolution , customary on - line instrumental data compaction , and absence of specific interest in the existence of ...
Página 81
... bandwidth and propagation requirements dictate some frequency allocation scheme there as here . We have , so far , no reason to search any frequency band outside the low noise , free - space microwave window ; and since signal stability ...
... bandwidth and propagation requirements dictate some frequency allocation scheme there as here . We have , so far , no reason to search any frequency band outside the low noise , free - space microwave window ; and since signal stability ...
Página 82
... bandwidth ( B ) is limited to about the range 103 Hz < B < 106 Hz These limits are uncertain by perhaps a factor of 10 and , since bandwidth is an important search dimension , point source scintillation and pulsar pulse - shape studies ...
... bandwidth ( B ) is limited to about the range 103 Hz < B < 106 Hz These limits are uncertain by perhaps a factor of 10 and , since bandwidth is an important search dimension , point source scintillation and pulsar pulse - shape studies ...
Otras ediciones - Ver todas
The Search for Extraterrestrial Intelligence, SETI Philip Morrison,John Billingham,John Wolfe Vista completa - 1977 |
The Search for Extraterrestrial Intelligence, SETI Philip Morrison,John Billingham,John Wolfe Vista completa - 1977 |
The Search for Extraterrestrial Intelligence, SETI Philip Morrison,John Billingham,John Wolfe Vista completa - 1977 |
Términos y frases comunes
Ames Research Center antenna Arecibo array astrometric bandwidth beam biological capabilities CETI clouds collecting area COMPLEMENTARY DOCUMENT cosmic cost cultural Cyclops density detection direction distance Earth Earth-based electromagnetic emission energy extraterrestrial civilizations extraterrestrial intelligence factors flux level frequency band galactic Galaxy ground-based hydrogen interstellar communication interstellar medium interstellar search Jesse Greenstein Jet Propulsion Laboratory main sequence maser microwave window NASA noise observations Observatory optimum orbit Philip Morrison planetary systems planets polarization possible present problem Project Cyclops pulsars pulse radar radial velocity radiation radio astronomy radio frequency interference radio telescopes range received resolution satellite Science Workshop scientific search for extraterrestrial search for signals search strategy search system Section sensitivity SETI Program Office SETI system signals from extraterrestrial solar system sources space spectral type spectrum star formation stellar studies techniques temperature terrestrial transmitters University W/m² water hole wavelength
Pasajes populares
Página 8 - Some conjecture that we might hear from nearimmortals the views of distant and venerable thinkers on the deepest values of conscious beings and their societies! Perhaps we will forever become linked with a chain of rich cultures, a vast galactic network. Who can say? If it is true that such signals might give us, so to speak, a view of one future for human history, they would take on even greater importance. Judging that importance lies quite outside the competence of the members of this committee,...
Página 177 - L, libration point of the Earth-Moon system, a point at lunar distance but on the opposite side of the Earth from the Moon. Among several desirable features of an orbiting antenna system are the complete sky coverage, the ability to track a given star continuously if a signal is detected, the reduced system temperature, and the potential structural simplicity and longevity made possible by the weightlessness and benign environment. Further studies are needed of the space-based SETI and of the alternatives...
Página 271 - Tyler, director, Center for Advanced Study In the Behavioral Sciences, 202 Junipero Serra Boulevard, Stanford, Calif.
Página 193 - Services; (j) that available technology will allow a search for these signals from the earth, from earth-orbit, and, eventually, from the moon and to minimize interference, certain locations on earth and in space may be preferred; DECIDES that the following question should be studied: 1. what are the most probable characteristics of radio signals which might be broadcast by extraterrestrial civilizations and the technical characteristics and requirements of a system to search for them; 2. what are...
Página 8 - Other imaginative and enthusiastic speculators foresee big technological gains, hints and leads of extraordinary value. They imagine too all sorts of scientific results, ranging from a valid picture of the past and the future of the Universe through theories of the fundamental particles...
Página 30 - US space program has provided not only excitement and scientific knowledge, but numerous practical satellite services not for this country alone, but for the whole world. It is in this same spirit of providing a focal point for international cooperation and support that we feel the US can and should take the initiative in SETI. The material, technological and intellectual resources of the US are such that a large-scale SETI program could be carried on indefinitely by this country alone without appreciable...
Página 192 - Technical criteria for allowable spurious radiation from out-of-band uses, iv) Phase-out of interfering uses now operating in the protected bands. Subsequent to the Science Workshop deliberations and during the preparation of the final report, the SETI radio frequency protection need received its first international recognition.
Página 19 - For these reasons it is premature to adopt only one strategy to the exclusion of others. To cover a wide range of other possibilities it is recommended that in addition to a high sensitivity search of nearby stars, there also be a complete search of the sky to as low a flux level and over as wide a frequency band as practicable.
Página vii - It is precisely because I believe theologically that there is a being called God, and that He is infinite in intelligence, freedom, and power, that I cannot take it upon myself to limit what He might have done.
Página 216 - ... to the character of the signals. Thus the problem of methodically searching for signals from extraterrestrial civilizations will include the following aspects: a) a search for sources of radiation with respect to direction, frequency, and time; b) an analysis of the structural properties of the radiation; c) determination of its artificial nature. Accordingly, this program provides for the following steps in research activity: 1 . Search for and selection of sources according to preliminary criteria....