Editing 1609 in science (section)

==Exploration==
* April 4 – [[Henry Hudson]] sets out from [[Amsterdam]] in the ''[[Halve Maen]]''.<ref>{{cite book|last=Hunter|first=Douglas|year=2009|title=Half Moon: Henry Hudson and the voyage that redrew the map of the New World|location=London|publisher=Bloomsbury Press|isbn=1-59691-680-X|page=[https://archive.org/details/halfmoonhenryhud00hunt/page/11 11]|url=https://archive.org/details/halfmoonhenryhud00hunt/page/11}}</ref>
** August 28 – Hudson finds [[Delaware Bay]].
** September 11–12 – Hudson sails into [[Upper New York Bay]]<ref>{{cite web|url=http://blog.insidetheapple.net/2008/09/new-yorks-many-911-anniversaries-staten.html|last=Nevius|first=Michelle|author2=James|title=New York's many 9/11 anniversaries: the Staten Island Peace Conference|work=Inside the Apple: A Streetwise History of New York City|date=2008-09-08|accessdate=2011-10-25}}</ref> and begins a journey up the [[Hudson River]].<ref>{{cite book|last=Juet|first=Robert|chapter=Juet's Journal of Hudson's 1609 Voyage|year=1625|title=Hakluytus Posthumus, or Purchas his Pilgrimes|volume=4|editor=Purchas, Samuel|editor-link=Samuel Purchas}}</ref>