A very different perspective on the culture of science can be found in Dying Planet. This book is not a page-turner. The style is hyperacademic and wordy. As a scientist, I found Markley's approach, which examines science as a cultural enterprise and critically dissects our language, methods and beliefs, to be both enlightening and occasionally annoying--the latter mostly when the language became opaque and the analysis long-winded. The amount of serious scrutiny devoted to mediocre (but fun) films like Total Recall overestimates their importance as barometers of societal views and attitudes about the human future on Mars. The book is also sprinkled with numerous small but irritating errors that would have been caught in a careful once-over by a planetary scientist. But if you can deal with occasional passages about bringing Mars "within the semiotics of historical and experiential time" and "the ways in which Mars exists as a complex multidisciplinary object," there are many historical, literary, political and cultural nuggets--in particular, a reanalysis of the lingering impact on planetary science of the Martian canal theory of Percival Lowell, a planetologist who early in the 20th century suggested that the lines visible on Mars were the engineering works of an advanced race struggling to irrigate their drying, dying world.
Whereas previous writers have suggested that Lowell's influence quickly waned after 1920, Markley argues that this standard account "underestimates the ways in which Lowell's paradigm of a dying planet influenced scientific speculation about the composition of the Martian atmosphere, the character of its surface, and the nature of its putative life-forms." The idea of the canals, and of a relatively wet and clement Mars, persisted in scientific discourse up to, and even into, the Space Age. Markley shows that throughout the 20th century, reputable scientists held out hope for water and plant life on Mars even while spectroscopic evidence of temperature and atmospheric composition suggested otherwise. This history should give us pause today when we rejoice in the latest evidence for a possible bio-friendly Mars.
More than a century after Lowell's controversial observations, Mars remains the planet that lost its water and, probably, its capacity for life. It is now obvious that Mars cannot be flagrantly alive in the sense that Earth is. Today the question is, Can Mars be at least barely alive, with colonies holding out in underground lakes and hot springs? Possible signs of life continue to be the subject of debate and spur for further observations: 100 years ago it was the canals; 50 years ago, ephemeral hints of chlorophyll were seen and later discredited. Today we see traces of atmospheric methane that just might be the breath of underground survivors. Meanwhile the rocks, mute witnesses to the real Martian story, are beginning to talk under the patient scrutiny of the Mars Exploration Rovers.
Markley might have a field day with some of the language in Roving Mars. Squyres seems obsessed with finding a "water story," even to the point of repeatedly implying that the success of each rover's mission hinges on finding concrete evidence of rocks formed in or altered by liquid water. Now of course, "following the water" is important for figuring out the natural history of Mars and whether it might have been more life-friendly in the past. But isn't a robot geologist, especially the first one on a new world, successful if it simply learns any story the rocks have to tell? It doesn't seem quite right to launch an investigation committed to finding a certain answer. Even less so when that answer, "Yes, there was water here, at some uncertain time and for some uncertain duration," basically confirms the paradigm that has been developing since 1971, as Mariner 9 and subsequent orbiters have provided images and global maps showing abundant evidence for flooding and channel formation. Ultimately the tremendous success of this mission goes much deeper than a simple verification of this widespread belief. Mars has myriad stories to tell. If water is what we seek, then that's what we'll find.