When we travel from one point on the globe to another point, we frequently go through a ‘time zone’ such that travelling east to west the clock moves back one hour. Seems quite rational but the entire Global picture is a bit more complex.

Lets imagine we are viewing the earth from northern stellar view.

Some interesting things are evident.

• There are 24 time zones corresponding with the hours of the day.
• Noon is always directly facing the sun and midnight is opposite on the Globe.
• The earth rotate towards the East, yet wind and weather come from the West so the atmosphere is rotating faster than the land mass on average.

At first glance this seems quite straight forward. So a ‘new day’ would always begin (Midnight) in the time zone furthest from the sun and the day would be half over when the earth rotated to the time zone closest to the sun (Noon). Now though there is another complexity to consider and that is the International Date line which runs roughly through the middle of the Pacific ocean. So if one travels East to West and passes through the international date line the date is advanced 24 full hours. Hence a full day is lost or gained depending on which way you cross the date line.

Trying to put the whole picture together, I find it is best to imagine the earth is rotating inside a fixed shell of see through plastic timezones which are fixed in space with noon facing the sun and midnight opposite. 6PM would be due east and 6AM do west. Now lets imagine the earth has rotated such that the Pacific ocean and the Date line is in the Noon slot facing the sun. The 1PM slot would be east and it could be Monday at 1PM while the 11AM slot would be one slot west and it would be Tuesday at 11AM. At this precise time, when the date line is in the noon slot, The earth is half Monday and half Tuesday.

Now if the earth rotates another 6 hours so the international date line is in the 6PM slot, Now only 6 hours of Monday is present on the earth. Namely the 6 time slots from 6PM to Midnight. However complicating this is that on the east side of the date line it is Monday at 6PM and on the west side Tuesday also at 6PM or a full 24 hours difference.

To complete this, lets rotate the earth so the Date line is in the midnight slot away from the sun. The Easterly 1AM slot would be Tuesday and the 11PM slot would be Monday and all seems normal .