Planetary Astronomy; an Appraisal of Ground-Based Opportunities (1968) / Chapter Skim
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Perspectives
Perspectives
Pages 1-6
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From page 1... ...
There is reason to believe that despite their diversity the planets, satellites, asteroids, comets, and meteorites have a common origin: that they were created about five billion years ago at the same time the Sun condensed from the interstellar medium. Our present concern is to understand the planetary system -- the details of its makeup and the relationships among its members.
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From page 2... ...
One is the advent of the digital computer; the other is the tremendous increase in the range, accuracy, and resolution of radar, which adds the dimension of distance to measurements previously confined to angular position. The distance accuracy already achieved is so great that, when combined with traditional optical angular techniques, an improvement of several orders of magnitude can be achieved in the determination of some important orbital parameters.
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From page 3... ...
Finally, the opportunity to study the general and local circulations as well as condensation and deposition processes in atmospheres having radically different compositions, Coriolis forces, and heat budgets than our own will provide rigorous tests for meteorological theories that presently are limited to a single example. A knowledge of the structure and composition of planetary interiors is important not only to a better understanding of the present state of the planetary system but also to understanding the manner in which the planetary system was formed and in which it evolved.
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From page 4... ...
Since space measurements demand such long preparation, any new information their designers can get is of great importance. For example, improved ground-based measurements of the surface pressure of the Martian atmosphere supplementing data from the radio occultation experiment aboard Mariner IV have provided important data for the design of a Martian lander.
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From page 5... ...
However, if ground-based astronomy is to make an effective contribution, the time element is an important factor: observations can be used best if the data are obtained and analyzed as far in advance of flights as possible. An additional time constraint is that the planets can be observed to advantage only at certain times: the most favorable times for observing Mars occur for only a few months every two years (Figure 1)
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From page 6... ...
We are fortunate that modern equipment and new observing techniques are becoming available at this time; the techniques of ground-based astronomy not only provide an opportunity to enrich our knowledge of the solar system but should also make it possible to ensure greater effectiveness in planning the space program.
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