Google's cute doodle for the Leap Day (29th February) 2024.
WHAT IS A LEAP DAY/YEAR?🤔🧐
Common/Calendar Year (y)=365 solar days 🗓
Solar/Tropical/Astronomical Year (Y)=365.2425 solar days🌏🌞
Y-y=0.2425; 4*(Y-y)=0.97=1-0.03 (+1 if divisible by 4)
100*(Y-y)=24.25=(25-1)+0.25 (again -1 if divisible by 100)
400*(Y-y)=97=4*(25-1)+1 (again +1 if divisible by 400)
That is to say,
Using logical and modulo operators, the year n is said to be a leap year if and only if:
(n mod 4=0)∧((n mod 100≠0)∨(n mod 400=0)).
In other words, a year is a leap year if it is evenly divisibly 4, except for years that are evenly divisible by 100 but not evenly divisible by 400.
For example, 2024 and 2028 are leap years; 2100 and 2200 are not, but 2400 and 2800 are.
This is our clever method to ensure that our calendar stays aligned with our seasons or Earth's orbit over time. If nothing were done about this discrepancy, our calendar would slowly drift out of sync with the Earth's orbit and seasons. After 100 years, we would be off by about 25 days! So, to fix this, we add an extra day, February 29, to the calendar every four years, with the exception that a year evenly divisible by 100 is not a leap year unless it is also evenly divisible by 400 (as shown in the calculations).
#LeapDay #LeapYear #Feb29 #February29 #29Feb #29February #ExtraDay #February #Earth #Sun #SolarYear #SolarDay #Astronomy #Calendar #CommonYear #CalendarYear #TropicalYear #AstronomicalYear #Season #Seasons #EarthOrbit #OrbitEarth #Year #Discrepancy #Discrepancies #Synchronization