The "Observational Cosmology Group" in the Physics Department, University of Wisconsin - Madison, has a nice site that covers some historical cosmological miscues as mankind has tried to discover our place in the universe. This
webpage has a brief history of how our view of the universe has evolved. The details of this history are really fascinating!<br /><br />------------------<br /><br />In my opinion; one of the worst astronomy blunders ever was Percival Lowell' (1855-1916) and his canal - "Canali" SNAFU which set astronomy back ten years...<br /><br />Lowell was one of the best known observers of the planet Mars. He established an observatory (now Lowell Observatory ) in Flagstaff, Arizona for the express purpose of observing the Martian "canali" <sup>1.</sup>, which Lowell mistranslated as "canals". He concluded that these canals were built by intelligent beings to supposedly supply water from the melting polar caps to a desert world.<br /><br /> Lowell's misunderstanding and overactive imagination led to the notion that Mars was inhabited by intelligent beings who were capable of planet wide engineering projects, and is the source of many science fiction stories about the red planet.<br /><br />1. The Italian astronomer Giovanni Schiaparelli in 1877 was the first to report the presence on Mars of "canali", an Italian word meaning naturally occurring channels, like river channels.<br />