Oceanography & Navigation: Key Concepts, Historical Figures, and Earth's Oceans

Nuclear fusion

A nuclear reaction where small atomic nuclei, mainly hydrogen, join together under extremely high heat and pressure to form heavier elements like helium.

Density Stratification

The process where gravity separates materials into layers based on their density.

Condensation theory

The theory that stars and planets form from a large, rotating cloud of gas and dust called a nebula.

Cyanobacteria

Tiny, single-celled organisms that use sunlight to make energy.

Hydrothermal vents

Mineral-rich openings on the ocean floor, usually found along ocean ridges.

Circumnavigate

To travel completely around the world by ship or aircraft.

Chronometer

A very accurate clock designed for use on ships.

Latitude

Imaginary horizontal lines that run east to west around Earth.

Longitude

Imaginary lines that run from the North Pole to the South Pole.

Sea Power

A country's ability to use its navy, control important ocean routes, and dominate sea trade.

Compass

A navigation tool with a magnetized needle that points toward magnetic north.

Polynesians

Skilled Pacific Ocean navigators who used waves, wind, birds, and the stars to travel between and settle islands.

Vikings

Scandinavian sailors, warriors, and explorers who built longships and explored the North Atlantic.

Ming Dynasty

A Chinese dynasty during which Admiral Zheng He led seven large treasure fleet voyages across the Indian Ocean.

Eratosthenes

An ancient Greek scholar who calculated Earth's circumference by studying the angles of shadows and using geometry.

Prince Henry / Sagres School

A Portuguese prince who supported a center at Sagres for navigation, mapmaking, and shipbuilding.

Christopher Columbus

An Italian navigator who sailed for Spain and reached the Americas in 1492.

HMS Endeavour / James Cook

British Royal Navy captain James Cook who led three scientific voyages to the Pacific.

Ferdinand Magellan / Juan Sebastián Elcano

Magellan led the first European expedition that attempted to sail around the world.

HMS Challenger & Challenger 2

The original HMS Challenger sailed from 1872-1876 on the first major scientific expedition focused on studying the world's oceans.

US Exploring Expedition / LT Charles Wilkes

A U.S. scientific expedition that took place from 1838-1842.

Matthew Maury & Benjamin Franklin

Benjamin Franklin studied and mapped the Gulf Stream; Matthew Maury created one of the first systematic studies of oceanography.

Early Exploration

People explored the oceans for survival, food and coastal resources, trade, finding new land, and migration.

European Age of Discovery

Europeans explored mainly to find sea routes to Asia for valuable goods such as spices and silk.

Contemporary Funding

Today, ocean exploration is supported by governments and scientific organizations.

Volcanic Outgassing

As early Earth cooled, volcanoes released water vapor, carbon dioxide, and other gases into the atmosphere.

Comet & Asteroid Impacts

Early Earth was hit by icy comets and water-rich asteroids that may have delivered additional water to Earth's surface.