1. LONGITUDE (to measure East-West), is all a matter of time…

2. 15° 30° 45° LONGITUDE (to measure East-West), is all a matter of time…
TIME ON BLUE MERIDIAN:
1400
1200
1500
1300
OVERHEAD SUNLIGHT
15°
30°
45°

3. WEST Morning Noon Afternoon EAST 15°
LONGITUDE (to measure East-West), is all a matter of time…
WEST
EAST
Morning
OVERHEAD SUNLIGHT
15°
Noon
Afternoon

4. PRIME MERIDIAN 0°
120°
15° TIME ZONES

5. Time at 0° Longitude is called Greenwich Mean Time, Universal Time Coordinated (UTC), ZULU time, etc.

6. Monday afternoon and night15 30
-15 45 60 75 90
-30
-45
-60
-75
-90
-105
-120
-135
-150
-165
165
150
135
120
105
180
It is now 1400 along the prime meridian. If it is Monday in London, what day is it at other locations around the world?
As the earth rotates 15° the local time on the meridians advances one hour
The local time in each time zone: 1200 along the ° meridian
There must be a meridian where the day changes. It is the 180° meridian along which is plotted the International Date Line.
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
0000
0100
0200
0300
0400
0500
The day changes at midnight, 0000, right?
Monday Tuesday
MONDAY
TUESDAY
Tuesday continues around the world
MERIDIANS
TUESDAY
WEST
NOON SUNLIGHT
Monday
Tuesday
Prime Meridian
International Date Line
EAST
MONDAY
MONDAY
Monday afternoon and night
Monday here
Two different days at the same place???