 | ||
|
Homepage Preventing Flight Problems Prior to the Flight During the Flight Medical Problems Pregnancy Flying with Kids Deep Vein Thrombosis What is DVT? |
|
|
| ||
Time Zones
Flying across time zones is the main cause of jet lag. Our regular circadian sleep-wake patterns are upset when we fly, because different regions of the world experience daylight and night time at different times due to the curvature of the earth.
The earth is divided into 24 time zones each approximately 15 degrees wide, these constitute one hour in time difference. So, say we started in London (Greenwich Mean Time), and travelled across three 15 degree time zones, depending upon the direction we would arrive either three hours before (west) or three hours after (east) the time in London.
The meridian (middle line) for all these time zones is found running through Greenwich, London.
Directly opposite meridian line is the International Date Line. Here, both time zones meet and so we encounter the point where there is a difference in days, so that when it is light on one side of the earth it is dark on the other.
The international date line is not straight, to avoid creating different time zones with a single country, thus it zigzags its way across the globe.
For a full listing of world time zones, click
here