The International Dateline...

The world is round, [surprise], and divided into 24 time zones. When this system was in the making, the 'centre' of the time zone was established at Greenwich near London. Therefore the 'end' of the time zone was 12 hours [east or west] of Greenwich. That happens to fall in the Pacific Ocean just a bit east of New Zealand. It should be a straight line from the north to south, but in effect it wiggles a bit so some island countries are not in two time zones.

So, what happens when you cross the dateline? That depends which way you are going, east or west.

Tonight, at 2:00 AM we will ADVANCE OUR CLOCKS 24 HOURS. That moves us into the next date [day]. We just happen to be at or near the dateline in a ship at night so the captain can do it then. If we were crossing in daylight it could be done anytime.

Because we are doing it at night there will not be a photo of the dateline.

The day that was 'lost or gained' [east bound or west bound], is an accumulation of the hours that were 'lost or gained' while travelling around the world or a portion of it.

End of the lesson, there will be an oral exam, later.

E.&O.E.

Today we are in Samoa, not American Samoa, or Western Samoa as it is currently called, but Samoa, as informed by our lecturer now on board.