Flashcards in History of Oceanography & Polynesian Voyaging Deck (15)
1) Austronesian speakers settle New Guinea and Philippines ~20,000 yrs ago
2) Settle Fiji ~1,300 yrs ago
3) Tonga ~1,100 yrs ago
4) Samoa and Marquesas 500 BC
All colonizing was probably deliberate
Why have much of Polynesian (esp. Hawaiin) voyaging knowledge was lost?
In part because navigation techniques were secret and taught only to very select groups of people.
How did Polynesian voyagers steer their course(s)?
Courses steered by rising and setting/rising stars, sun, wind, and waves
How did Polynesian voyagers figure out their position relative to nearby islands?
Home reference system by observing their surroundings very accurately. Unlike the self-centered reference system (compass). Use deflected swells, homing birds, cloud patterns, reflection of land in sky, etc.
Library of Alexandria
Kept scrolls from ships and land caravans. After its destruction, much knowledge was lost, society regressed, and the Dark Ages ensued.
~200 BC: discovered Earth was round and calculated its size
~140 BC develops 360 degree system
~120 AD: adds minutes and seconds to the 360 degree system; recalculated the size of Earth but got it wrong
Colonized Iceland ~700 AD
Discover Greenland & N. America ~990 AD
As climates changes, Viking empire declines
What was the longitude problem?
The only way to fix longitude was with time, but that was not possible due to the fact that all clocks at the time were powered by pendulums. Harrison developed the first chronometer.
How can you measure longitude using time?
You must know the time where you started your journey from. Record the time the sun is directly overhead at your new position while traveling. Compare this time to the time at your starting point. Every hour later than mid-day at at the starting position = 15 degrees longitude to the west.
Why can you measure longitude using time?
Earth has 360 longitudinal degrees and has 24 hours
360/24 = 15
1838-1842: 6 vessels mapping areas, collected specimens (now in the Smithsonian collection). May have been the first to discover Antarctica. Court-martialed on return.
First expedition devoted entirely to science/directed by scientists. Found life in the deep-sea using probes disproving Forbes theory