Pluto looms large in Flagstaff, where residents and businesses alike take pride in their community's most enduring claim to fame: Clyde Tombaugh's 1930 discovery of Pluto at Lowell Observatory. Percival Lowell began searching for his theoretical Planet X in 1905, and Tombaugh's eureka! experience brought worldwide attention to the city and observatory. Ever since, area scientists have played leading roles in virtually every major Pluto-related discovery,...