Navigational novelties

Knowing WHERE YOU’RE GOING

Sailors would be completely lost without these ingenious inventions. They have allowed explorers to travel the world and discover new lands.

Without navigational aids, sailors would rarely sail out of sight of land.

The oldest map ever found is 12,000 years old.

Map

Simple maps of the heavens and of geographical features were carved onto cave walls thousands of years ago. Gradually, they became more detailed and useful. PTolemy, a Greek astronomer who lived in Egypt in the 2nd century, drew maps that included lines of longitude and latitude. His ideas revolutionized mapmaking when his maps were rediscovered by Europeans in the 1400s. Their maps became much more accurate.

As new lands were discovered, the modern world map took shape.

Compass

The Chinese were using compasses during the Qin dynaSTy (221–206 bce) to make sure that buildings were facing the right way for good fortune. The spoon-shaped needle was made from lodestone, a naturally magnetized mineral that always points toward magnetic north. Around the 11th century, compasses began to be used for navigation.

Mariner’s astrolabe

Sailors used astrolabes, first made around 1300, to measure the height of the sun or a particular star. This allowed them to calculate their latitude (north–south position). Mariner’s astrolabes helped sailors explore faraway lands in a period known as the Age of Discovery, from the 1400s to the 1600s.

Marine sextant

Sextants (meaning sixths) use mirrors to measure the angle of the Sun or the North Star in relation to the horizon at particular times of day. Like the astrolabe, this allows sailors to work out their north–south position. The first one was made by English astronomer John Bird in 1757. They are still used today— if onboard computers crash, mariners can find their way with a sextant. The arc of a sextant is one sixth of a circle (60 degrees). Did you know? Marshall Islanders memorized stick charts, made from coconut fronds, to map ocean swells and navigate the Pacific by canoe.

Satellite navigation

Today, there are networks of satellites in space that allow users to pinpoint their position almost anywhere on earth. A receiver compares time signals from four or more satellites. To determine its exact location, the receiver calculates the distance to each satellite. Today, most sailors rely on satellites to safely navigate through the world’s waters—and many cars and cell phones have satellite receivers, too.