Final answer:
To determine a date on Earth's position in a diagram, knowledge of how the International Date Line affects dates across time zones is crucial, such as the case with Pearl Harbor being recorded on different dates in the US and Japan. This line adjusts the calendar day when crossed to maintain consistent global timekeeping.
Step-by-step explanation:
To determine a date represented by the Earth's position in a diagram, it is essential to understand the International Date Line and how time zones affect dates across the globe. The concept of the International Date Line was established following incidents such as Magellan's circumnavigation, whereupon returning to Europe, sailors discovered they were one day behind on their calendar. This discrepancy occurs due to Earth's rotation; as they traveled westward, they counteracted Earth's eastward rotation.
The International Date Line serves as an arbitrary line, mostly along longitude 180°, facilitating global timekeeping. When crossing the International Date Line from west to east, you subtract a day, and when crossing from east to west, you add a day. This ensures that the date changes consistently worldwide and prevents confusion that can arise when different regions on Earth could otherwise claim it to be two different dates simultaneously.
An example of the importance of understanding the International Date Line is the bombing of Pearl Harbor, which occurred on December 7, 1941, in Hawaii, but is recorded as December 8 in Japan due to their position relative to the date line.