Leap Years and Leap Day

Intercalary Days

The concept of intercalation is essential for aligning calendars with the solar year. Gary Arndt explains that intercalary days, like February 29, are added to correct the calendar's drift from the solar year. He notes that while the Gregorian calendar is effective, future adjustments may be necessary, such as excluding leap years for years divisible by 4000 or including them for years divisible by 20,000 1.

   

Calendar Proposals

Permanent calendar proposals aim to maintain consistency without frequent adjustments. Gary Arndt discusses the Hanke-Henry Permanent Calendar, which suggests a 364-day year with a leap week every five or six years to maintain alignment with the solar year 1. He also highlights the evolution from the Roman to the Julian and Gregorian calendars, emphasizing the need for precision in aligning with the solar year 2.