Clyde W. Tombaugh

A survey of long-term observational behavior of various martian features that affect some recently proposed interpretations

Abstract In recent years an unprecedented surge of papers and articles has appeared in which various authors interpret the features and conditions on Mars. In many cases it is obvious that there was little or no personal telescopic acquaitance with the appearance of Mars under very favorable viewing conditions, nor with the complex behavior of various features and phenomena throughout all of the martian seasons. This trend can lead to a dangerous amount of misinformation and confusion. The study of Mars requires a familiarity with several different disciplines that few have met. It requires 15 years to follow Mars through one equivalent year of seasonal changes; at least two or three times 15 years is necessary to discern secular changes from the regular seasonal changes. One needs to peruse a long list of papers in the disciplines of physics, geology, meteorology, and biology to sift the evidence. A consideration of the life history of solar-type stars, the stability of the solar system, and paleoclimatology shows that Mars could never have provided an environment of other than cool to frigid temperatures and a dry climate. Consequently, the role of water on martian geology would have been very insignificant. Water denudation and the formation of marine sedimentary rocks could never have occurred. Some volcanism probably occurred. The canals and angular maria probably are features of extensive crustal faulting. The surface would be highly cratered by asteroid impacts; the round dark dots may represent impact sites. The considerable seasonal differences in maria color, polar cap phenomena, and climate between the northern and southern hemispheres appear to be related to the perihelion and aphelion positions in the orbit. Many proposed explanations of the nature of the various features are simply not supported by the complex observed phenomena. The author proposes some explanations that appear to be in accord with his experience with the planet Mars.

Some early vexing optical and mechanical problems of the 13-inch “Pluto” telescope

Abstract The circumstances relating to the initiation of the final search for Lowells Planet X are summarized as an introduction, followed by a description of the planning and fabrication of the 13-inch astrograph. In the final trial testing of the new instrument, several difficult problems were encountered. One by one, these difficulties were overcome, some by minor modifications of the equipment, and some by changes in the observational procedure. The solutions to each of these problems are described. These were vital before a successful planet search could be started. Reasons ae given for extending the planet search over a large sky area.

THE HISTORICAL DISCOVERY AND RECENT CONFIRMATION OF A NEW CATACLYSMIC VARIABLE IN CORVUS

During the trans-Saturnian planet search of Lowell Observatory, Tombaugh exposed and studied 362 pairs of plates during the years 1930-44. Among other discoveries he found a nova candidate that appeared on a plate taken on March 23, 1931. This star has stayed in obscurity since that time, its only record being that of Tombaughs notes written on the plate jacket. On March 23, 1990, this star again went into outburst. Observational studies during this recent outburst and one month later during quiescence have shown this star to be a high-galactic-latitude cataclysmic variable. A total of 11 historical outbursts are now known for this object, all of which have a maximum near V = 13.0, 6.5 magnitudes above its current quiescent value.

Geology of Mars

Publisher Summary This chapter presents the former interpretations of Mars and provides an explanation of map of Mars. The dark patches on the moon were thought to be oceans of water and likewise the dark markings on the disk of Mars. The chapter discusses polar phenomena and orbital relations of Mars. Every martian year, the shrinking polar cap of the summer hemisphere develops a dark border. There is a marked consequence of orbital eccentricity and time of solstice in Mars. The chapter describes orbital eccentricity and seasonal meteorology of Mars. It also elucidates erosion on Mars. On Mars, water erosional transport does not exist and wind transport is minor in comparison. The chapter further discusses seasonal phenomena: indicators of certain topographic features of Mars and consequences of impact from foreign bodies in Mars. With a lesser force of gravity, the crust of Mars should be two to three times thicker from the standpoint of rock weight and pressure. Water plays a very dominant role in terrestrial geology, geomorphology, and mineralogy. However, on Mars, it must be quite different. In the absence of oceans, no sedimentary beds of limestone, sandstone, shale, cemented conglomerate, and volcanic tuff could have formed. The chapter reviews some mineralogical consequences in Mars. It mentions some of the more common minerals likely to be missing on Mars.