Editing Alfred Russel Wallace (section)

=== Astrobiology ===
Wallace's 1904 book ''[[Man's Place in the Universe]]'' was the first serious attempt by a biologist to evaluate the [[planetary habitability|likelihood of life on other planets]]. He concluded that the Earth was the only planet in the [[Solar System]] that could possibly support life, mainly because it was the only one in which water could exist in the [[liquid phase]].<ref name="Kutschera 2012">{{cite journal |last=Kutschera |first=Ulrich |author-link=Ulrich Kutschera |title=Wallace pioneered astrobiology too |journal=[[Nature (journal)|Nature]] |volume=489 |issue=7415 |year=2012 |doi=10.1038/489208e |pages=208 |pmid=22972286 |s2cid=4333070 |doi-access=free }}</ref> His treatment of [[Mars]] in this book was brief, and in 1907, Wallace returned to the subject with the book ''[[Is Mars Habitable?]]'' to criticise the claims made by the American astronomer [[Percival Lowell]] that there were [[Martian canals]] built by intelligent beings. Wallace did months of research, consulted various experts, and produced his own scientific analysis of the Martian climate and atmospheric conditions.{{sfn|Slotten|2004|p=474}} He pointed out that [[spectroscopic analysis]] had shown no signs of [[water vapour]] in the [[Martian atmosphere]], that Lowell's analysis of Mars's climate badly overestimated the surface temperature, and that low atmospheric pressure would make liquid water, let alone a planet-girding irrigation system, impossible.<ref>{{cite web |last=Wallace |first=Alfred |title=''Is Mars Habitable'' (S730: 1907) |url=http://www.wku.edu/~smithch/wallace/S730.htm |publisher=The Alfred Russel Wallace Page hosted by [[Western Kentucky University]] |access-date=13 May 2007 |archive-url= https://web.archive.org/web/20070405172431/http://www.wku.edu/~smithch/wallace/S730.htm |archive-date= 5 April 2007 |url-status=live}}</ref> Richard Milner comments that Wallace "effectively debunked Lowell's illusionary network of Martian canals."<ref>{{cite web|title=A Wet Red World? The Search for Water on Mars Goes On |last=Milner |first=Richard |work=Astrobiology Magazine |date=4 November 2011 |url=http://www.space.com/13510-water-mars-search-life.html |access-date=22 November 2012}}</ref> Wallace became interested in the topic because his anthropocentric philosophy inclined him to believe that man would be unique in the universe.{{sfn|Shermer|2002|p=294}}