GEOL-103 Lecture Notes - Lecture 1: Vikings, Nansen Bottle, Sustainable Fishery
Document Summary
Polynesia- pacific islanders" area of colonization was large ~2500bc, 1500bc=widespread. How does one navigate? follow coastline- stay in sight of land map places and general direction during day: use sun/time of day during night: use stars star position is not constant (except for n star) In open ocean- need to know latitude (h) and longitude (v) keeping time is very important. 2500bc-800ad used star compass and stick navigational charts knowing accurate position of stars helps locate ships position height of north star relative to horizon gives latitude (n hemisphere) Middle ages (500ad-1500ad) used sextant to determine latitude longitude=more complicated: used primitive clocks to determine longitude (knowing time=key) Chinese (1405-1433) large fleet exploration/trade/technology invented compass- constant measurement. Reverse tribute - display wealth and power of ming dynasty and to show kindness to people of distant places. Magnetic field protects planet used by organisms for navigation (ie: birds: north magnetic pole moves!
