Editing Edwin Hubble (section)

===Doctoral studies===
[[File:Hubble identity card.jpg|right|thumb|upright=1.2|Hubble's identity card in the [[American Expeditionary Forces]].]]
After the [[United States declaration of war on Germany (1917)|United States declared war on Germany in 1917]] during [[World War I]], Hubble rushed to complete his Ph.D. dissertation so he could join the military. Hubble volunteered for the [[United States Army]] and was assigned to the newly created [[86th Infantry Division (United States)|86th Division]], where he served in the 2nd Battalion, 343rd Infantry Regiment. He rose to the rank of major,<ref>{{cite news |title=Major Edwin Hubble is Made Lieutenant Colonel |url=https://www.newspapers.com/search/#lnd=1&query=Major+Edwin+Hubble+is+Made+Lieutenant+Colonel&t=965 |access-date=October 19, 2015 |work=Springfield Missouri Republican |date=August 11, 1918 |page=6}}</ref> and was found fit for overseas duty on July 9, 1918; the 86th Division moved overseas, but never saw combat as it was broken up and its personnel used as replacements in other units. After the end of World War I, Hubble spent a year at [[University of Cambridge]], where he renewed his studies of astronomy.<ref>{{cite book |author=Christianson |first=Gale E. |title=Edwin Hubble: Mariner of the Nebulae |date=1996 |publisher=University of Chicago Press |isbn=9780226105215 |page=183}}</ref>