Cosmic Challenge by Harrington

Author:Harrington
Language: eng
Format: mobi
ISBN: 9780511853807
Publisher: Cambridge University Press
Published: 2011-02-28T16:00:00+00:00

87 Eye of Mars

No other planet in our Solar System appears so enticing, yet proves so frustrating, through backyard telescopes as the Red Planet, Mars. On the one hand, the planet's thin carbon dioxide atmosphere affords us a nearly cloud-free, round-the-clock view of its sun-drenched surface. On the other hand, however, the planet's small size coupled with its distance away conspire to shrink the planet's disk to no more than 25 across at its best. Usually, Mars appears far smaller than that. As a result, whatever surface details are visible through our telescopes prove small, vague, and tenuous, at best.

This contradictory set of conditions undoubtedly led to some of the controversial surface features that early Mars observers claimed to see. Without a doubt, the best-known case of Martian illusions has to be the widespread misconception that the planet is covered in a web of thread-thin canals. Many references attribute the “discovery” of Martian canals to the Italian astronomer Giovanni Schiaparelli. Viewing Mars in 1877, Schiaparelli saw what he interpreted as dark, thin lines stretching across the lighter areas of the planet's surface and connecting the darker regions. He described these vague markings as “canali,” which in Italian, means channels or grooves. Once his observations, published in 1878, reached the ears of English-speaking astronomers, canali was mistranslated to mean “canals,” which of course, are artificial waterways constructed by intelligent beings. Suddenly, the hunt for the Martians was on!

Actually, Schiaparelli was not the first person to see “canali.” At least half a dozen observers recorded linear features on Mars as far back as 1840. In 1867, Richard A. Proctor published a map of Mars based largely on observations and drawings by William Dawes (of “Dawes’ Limit” fame, discussed in Chapter 1). Proctor presumed that the darker parts of the planet were seas and the reddish tracts continents, and proceeded to name several features after English astronomers, such as Dawes Ocean, Herschel Continent, and Terby Sea.

Schiaparelli's 1878 report also included a map of Mars, showing far more detail than Proctor's, which contained several fanciful errors. To correct these errors, Schiaparelli decided to abandon any names previously assigned and instead create his own references based on biblical and mythological entities. Terby Sea, for instance, became Solis Lacus. For the most part, the names we still use when discussing features on Mars are those assigned by Schiaparelli. That is, minus the canals, of course.

While we may chuckle today at the thought of canals crisscrossing the planet, many of the surface features that perplexed generations of astronomers continue to intrigue observers today. Even with robotic spacecraft scurrying about the surface of the Red Planet or in orbit high above, Mars still beckons backyard planet watchers. There are many striking features across the Martian surface, from the fork-shaped Sinus Meridiani (or what Proctor had christened Dawes's Forked Bay) to the dark wedge of Syrtis Major (formerly Kaiser Sea).

Since it was first detected in the nineteenth century, the region Solis Lacus, located at Martian longitude 85° west and Martian latitude 26° south, has puzzled observers.

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