Ground-Based Astronomy A Ten-Year Program (1964) / Chapter Skim
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1 Introduction and General Statement
1 Introduction and General Statement
Pages 1-12
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From page 1... ...
DEVELOPMENT OF A WORLD PICTURE Astronomy is the oldest of the sciences. As soon as man could write, he preserûed his thoughts antl speculations about the universe around him on cuneiform clay tablets, on papyrus, and in the Greek anil Arabic documents that form our ieritage.
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From page 2... ...
This theory culminated in the Ptolemaic geocentric tables of planetary conffgurations. Unexplained discrepancies led certain visionaries to consider the sun rattrer than the earth to be the center of the world, but tlis hypothesis was so foreign to the ancient mind that not until the middle of the 16th century did Copernicus force a recognition of a heliocentric universe.
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From page 3... ...
Ànswers to some of these questions will undoubtedly come within the next decade; others, now only dimly perceiveil through the mists of present ignorance, must wait until ou¡ present larowledge can be broadened. Progress will be made by clever and aggressive use of telescopes of the largest size, equipped with detectors such as radio receivers, spectrographs, photometers, and photographic plates-instrùments that anaþze the faint incomíng radiation maile feeble by the enormorrs spreading out that has taken place in its long jourrrey ftom its place of origin to the earth.
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From page 4... ...
The discovery of ttre form of our galaxy in 1915 as a higtrly flàtened rotating disk of stars, with the sun and its attendant planets at a peripheral position 30,000 light years from its center, would not have been possible without the 60-inch reflector on Mount Wilson. The discovery of the tme nature of the extemal galaxies as separate island universes" was possible in Ig24 because the 36-inch Crossley reflector of the Lick Observatory ancl the 60-inch and 100-inch telescopes of Mount Wilson were available.
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Otlrer important U' S' cont¡iburt tions incluiled tÏe discovery of powerful sporadic railio emissions ftom e ¡adio receiver' Jupiter antl the development of the low-noise maser-type project at Harvard, started in 1953, produced the ,4. radio astronomy n ûrst Ph.D.'s in radio aitronomy.
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From page 6... ...
Railio astronomy studies today play key roles in all aspects of the study of space, and continued rapid growth of their role in astronomical research appears certain. Erpbding Galnsi¿s Perhaps the most important radio astronomy discovery was that ce¡tain rare antl unusual galaxies emit prodigious quantities of radio energy by 6 Copyright © National Academy of Sciences.
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From page 7... ...
The Crab Nebula, which is a lemnant of an ancíent supernova, is one such example, anil the exploding galaxy M82, shom in Figure 1, ís another. Direct evidence is available in M82 from optical polarization data to show that magnetic ûelds exist extending 10,000 light years from tlhe I center of the galaxy, and that high-energy electrons interacting with these r ffelds procluce the observed ¡ailiation.
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From page 8... ...
The identiûcation of further sources to the optical limit of our largest telescopes must be achieverl; their calculated distances are so much greater than those of previously identiffed individual obiects that cosmological moclels ean be put to an observational test. The spectral-energy distributions, redshifts, polarization, anil spatial distribution must be found.
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From page 9... ...
The recent resurgence of interest in planetary astronomy, encouraged t by the space program, has created new demands on existing large telescopes that likewise cannot be met. Commitments to programs already in progress v have made it dificult for observatories with large telescopes to divert time s to ground-based re-evaluation of many palameters of planets and their r atmospheres, r¡/hich are of vital importance in planning vehicular missions to I points in the solal system.
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From page 10... ...
, a number of smaller instruments capable of important bright+tar research anil training, two maiol array' type radio teiescopes capable of high resolution, two large paraboìic stðerable antennas of tle 300-foot class, and a number of special-purpose radio ínstruments for the unique problems of great importance. THE RELATION OF GROUND.BASED AND SPACE ASTRONOMY The foregoing recommendations, discussed and documented in Sections III and IV, are io, o"*
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From page 11... ...
opticaì identiÊcatÍon of the objects tlat emit X-ray and gammase ray radiation on direct photographs, followed by detailed spectrographic studies; (2) observation of the energy distribution in ordinary optical wave lengths of those stars for which extreme-ultraviolet data have been obtained, particular'þ those objects that show abnormalities; (3)
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From page 12... ...
If new facilities are not created, either tlrough private fulding or tluough government support, then gifted young astronomers will turn to other ffeldl tlre promise of astuonomy will remain unfulfflled, and .{merican astronomy ii will surely stagnate in this century. tl .:l 12 Ë Copyright © National Academy of Sciences.
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