What is longitude?
Longitude lines are defined as geographical coordinates used to determine the east and west points on the Earth’s surface. It’s usually expressed in degrees and is coupled with a latitude coordinate, which determines the north and south points of a longitude line.
The north and south poles:
All the longitude lines intersect at the north and south poles; this means that if you were to go to the north pole, you could theoretically walk in a small circle and have walked through every longitudinal degree on Earth!
Longitude and time zones
There are 360 degrees of longitude and 24 hours a day.
It means that every 15 degrees longitude is a new time zone, each time zone an hour apart.
The history of longitude
Naturally, humans were keen to define longitude in Geography terms that could benefit those traveling long distances. So in 190-120 BC, Hipparchus, a Greek astronomer, tried establishing longitude and latitude as coordinates. He started by making a zero meridian that passed through Rhodes. However, his method of carrying this project to completion required an accurate clock, of which none was.
Many scientists and astronomers attempted to figure out the distance between meridian lines. Still, it wasn’t until Galileo they managed to time the eclipses of Jupiter’s moons with a pendulum clock.
However, there was still an issue with establishing longitude at sea. It wasn’t until an ordinary clockmaker, John Harrison, from England, made a device that could set longitudes while sailors were seafaring. He found that if you established the time of the location in the sea by the sun’s angle and then compared that to the time of the timezone of Greenwich (the meridian line), you can decipher the distance traveled.