Final answer:
The time at a given place relative to Greenwich at noon depends on its longitude, with a one-hour time difference for every 15 degrees east or west. East of Greenwich, time is later by one hour per 15 degrees, whereas to the west, it's earlier by the same increment.
Step-by-step explanation:
The time at a given place, when it is noon at Greenwich, depends on the longitude of that location relative to Greenwich. The Earth rotates 360 degrees in 24 hours, which means it rotates 15 degrees every hour. Therefore, for every 15 degrees of longitude away from Greenwich, there is a one-hour difference in time. If we travel east of Greenwich, the local time will be later by one hour per 15 degrees. Conversely, if we travel west, the local time will be earlier by one hour per 15 degrees.
Since Greenwich represents the starting point for time zones at zero degrees longitude, if it is noon there, then:
- 15° to the east of Greenwich it will be 1 p.m.
- 15° to the west of Greenwich it will be 11 a.m.
The concept of Universal Time (UT) or Greenwich Mean Time (GMT) is used around the world for consistency in timekeeping and navigation.