Question

2 multiple choice 1 point
what is the purpose of a \leap day\ within leap years?
the length of a sidereal year does not correspond to an exact whole number of sidereal days.
the length of a tropical year does not correspond to an exact whole number of sidereal days.
the length of a sidereal year does not correspond to an exact whole number of solar days.
the length of a tropical year does not correspond to an exact whole number of solar days.
3 multiple choice 1 point
what would happen if we did not include an occasional extra day (leap day) in the yearly calendar?
the solar day would start to become shorter than 24 hrs
the difference between a tropical year and sidereal year would become greater.
the solar day would start to become longer than 24 hrs
the seasons would gradually start to drift towards different months of the year.

Explanation:

• Question 2:
• A tropical year (the time it takes for the Sun to return to the same position in the cycle of seasons) is approximately \(365.24219\) solar days (a day based on the Sun's position in the sky). Since it is not a whole number, we add a leap day (an extra day) in leap years to keep the calendar in sync with the seasons. A sidereal year (the time it takes for the Earth to complete one orbit around the Sun with respect to the fixed stars) is not directly related to the need for leap days in the calendar we use for seasons.
• Question 3:
• The length of a solar day is approximately \(24\) hours and is not affected by the inclusion or exclusion of leap days. The difference between a tropical year and a sidereal year is a fixed astronomical value and not affected by the calendar. If we do not include leap days, over time, the calendar dates will not match the seasons. For example, if a tropical year is about \(365.24219\) days and we use a \(365\) - day calendar, each year the seasons will be about \(0.24219\) days earlier relative to the calendar. Over many years, the seasons will gradually drift to different months.

Answer:

• Question 2: The length of a tropical year does not correspond to an exact whole number of solar days.
• Question 3: The seasons would gradually start to drift towards different months of the year.