Chapter 01b Ocean Exploration

 

History of Ocean Exploration

 

Migration into Polynesia

    prehistory (no written records)

    migration begins ~2500 BC

 

Early trade around the Mediterranean Sea

 

Phoenicians:  1500-1000 BC  

  earliest culture with extensive coastal trading

  homeland of Phoenicia equivalent to modern Lebanon & Israel

  continued until Carthage conquered by Romans in 146 BC

 

Phoenicians circumnavigated Africa; 

  the first to use the Pole Star for navigation;

  traded throughout the Mediterranean and into the Indian Ocean

 

Greeks:  from 500 BC, dominant culture in Mediterranean

  carried on coastal trading tradition of the Phoenicians

 

Map:  The world according to Herodotus, 450 B.C.

The early Greeks believed that the Mediterranean was surrounded by land, which was encircled by water.

 

Eratosthenes of Egypt, 276-192 BC

 

 

A librarian at Alexandria

Field “experiment” to determine the curvature of the Earth compared Sun angle in a well at Syene with the shadow of a wall in Alexandria

 

 

Calculated the Earth's circumference: 40,000 km (24,840 mi)

More precise, modern measurement:  40,032 km (24,860 mi)

 

Claudius Ptolemy: Astronomer and geographer 150 A.D.

 

 

The Ptolematic System was used to calculate the motions of the planets and other celestial bodies

Ptolemy developed the geographic system of latitude and longitude

 

 

The Geography (c. 150 A.D.), Ptolemy gives the prime objectives of cartography, and how to make maps on various regions. He discussed the known continents at that time: Africa, Asia, and Europe.

 

 

Ptolemy’s Atlas was considered without error at the time. 

However, it overestimated the Asian landmass, and grossly underestimated the width of the oceans.  A primary reason that Columbus thought that he had reached eastern Asia.

 

 

Cosmas' Map of the Known World (6th century A.D.)

 

With the decline of the Roman Empire, there was also a degeneration in geographic knowledge.  Religious dogma supplanted scientific inquiry and interpretations.  This map of the Earth is a flat rectangle.

 

Vikings Explore the North Atlantic

Starting in early 800s AD

 

Advances in ship building

Vikings colonized Iceland by 900 AD and settled Greenland.

They were the first Europeans to reach North America in 985. 

Normans (Vikings) conquer England 1066. 

Viking settlements collapsed with start of Little Ice Age (1430-1850).

 

 

 

 

 

 

Arabian Traders Sailed the Indian Ocean

 

From approx 800 AD

 

Arabian traders sailed the Indian Ocean, and possibly discovered New Zealand.

 

Major trading routes established by Arabs in the Indian Ocean; they took advantage of changes in the wind direction with the monsoons. 

Used magnetic compasses, invented by the Chinese in 4th Century.

Possibly discovered New Zealand: The passage at top is from Volume 6, where Al-Idrisi described an exploration by Arab explorers around 790 AD of the Southern Ocean, and their discovery of a large, mountainous land-mass.

South-east of New Guinea is nothing but ocean - and New Zealand.

 

Chinese – Coastal Trading in Southeast Asia

 

Early 1400’s – major exploration of the Indian Ocean and around Africa

 

Invented the compass around 200 AD

Probably started using for navigation 800-1000 AD

 

 

Admiral Zheng He (1405-1433)

 

Zheng commanded 317 ships and 37,000 men, and visited 37 countries. 

 

China greatly reduced all maritime trade after Zheng’s death.

 

Recent archeological evidence that Zheng probably circumnavigated the world ocean with a fleet of vessels;

colonized western South and Central America;

the death of the emperor and a series of calamities caused Chinese regime to expunge all evidence of the journey from state records

 

 

Western Europeans Begin Era of Exploration   Starting in 1400s

 

1441  Portuguese navigators cruise West Africa

1450  Prince Henry establishes a Naval observatory

1470  Portuguese discover Africa's Gold Coast

1492  Columbus sets sail

1497  Vasco da Gama rounds Cape of Good Hope and reaches India

1497  Cabot searches for Northwest Passage

1512  England builds double-deck warships

1519  Magellan begins global circumnavigation

 

1534  Jacques Cartier enters the St. Lawrence River

1577  Sir Francis Drake circumnavigates the globe

1609  Henry Hudson explores Hudson River

 

Magellan 1519-22

 

First European to circumnavigate the ocean

Killed in the Philippines in 1521

 

John Harrison’s Chronometer 1760

 

British and French were competing in technology as well as for empire-building

The chronometer was a major advance for navigation – allowed accurate determination of longitude

 

James Cook global cruises
            1768-71           1772-75           1776-80

 

British Navy recognized the need for detailed information about the coasts of the continents and the open ocean.  In support of maritime trade, and empire building.

Cook killed in Hawaii 1779

 

Benjamin Franklin 1770

Franklin, as U.S. Postmaster General, evaluated the routes of mail-carrying ships to and from Europe; discovered and charted the Gulf Stream.

Thomas Jefferson mandated charting of US coastal waters 1807

 

 

 

 

 

Early Scientific Investigations

1831  Charles Darwin on the HMS Beagle

1855  Matthew Maury publishes The Physical Geography of the Sea

1872 HMS Challenger sets sail from England

 

 

 

Voyage of the HMS Beagle 1831-36

 

 

Matthew Fontaine Maury

 

Director, U.S. Naval Depot of Charts & Instruments

 

1842  Wind and Current Charts

 

Recognized need for international cooperation

 

1855  The Physical Geography of the Sea

 

 “father of physical oceanography”

 

Voyage of the HMS Challenger 1872-1876

Equivalent today of a manned mission to Mars that discovered many new forms of life and studied the geology and physical processes of the planet

 

 

Major questions in mid 1800s:

 

  How deep are the oceans ?

  What is at the bottom of the deep ocean?

  Does life exist at the bottom of the ocean ?

 

 

 

Sir Charles Wyville Thomson, Chief Scientist

 

 

Voyage covered 69,000 nautical miles with 362 oceanographic stations 

 

Major Contributions of the Challenger Expedition:

  the first systematic plot of ocean currents and temperatures

  a map of bottom sediments

 

  an outline of the main contours of the ocean basins

 

  discovery of the mid-Atlantic Ridge and a record 26,900 feet (8,200 meters) in the Challenger Deep in the Mariana Trench

 

  the discovery of 715 new genera and 4,717 new species

 

  proof of abundant and diverse life at great depths in the ocean

 

Scientific results published in a 50-volume, 29,500-page report that took 23 years to compile

 

 

 

 

 

 

 

Fridtjof Nansen and the Fram

 

3 years in ice, to 84º N, drifted 2 km / day