February 29, which Google "honors" with today's doodle, is considered a special day, as it is only added to our calendar every four years. The time that includes such a day, such as today (February 29, 2020), is called a "leap year" and its history goes back a long way.
What is a "leap year"
"Leap year" is called the year that has 366 days, instead of 365 that the other years have. In the "leap year" an extra day is counted, essentially a twenty-four hour period, in order to correct errors caused by the imprecise calculation of the length of the day, a complete rotation of the Earth, in the measurement of the solar year.
The errors are due to the fact that with the time measurement system used today in the Western world (Gregorian calendar), each year is about six hours longer than the 365 days of the Julian calendar, to be exact 365.242199 days, or about 1/4 of the day, resulting in an error of the order of one full day being created every four years.
The story of the "leap year"
With the Julian Calendar, established by Julius Caesar according to the proposals of the Alexandrian astronomer Sosigenes (46 BC), February was moved from the last month of the year to the second, immediately after January and had 30 days. Between February 24th and 25th they added an extra day, meaning February 24th was counted twice. And because this day was the sixth day before the Kalends of March (March 1st), the second 24th of February that was added was called the bisixth day, that is, the second sixth day before March.
In time, the term leap year came to refer to the whole year having one day more than the common one. Later, a day was removed from February and another on August, added in honor of the emperor to the month of August. Thus, February remained with only 28 days. Since post-Christian times, the extra day is added to the end of February, which in a leap year has 29 days instead of 28.
Why is it considered grubby
Because in the past the people did not know the scientific explanation of the addition and because they had a tendency to "dress up" with supernatural properties everything they could not explain, they created various myths and beliefs around the "leap year" and the superstitions defined it as "Grusuziko" .
During Roman times, February was considered the month of the dead, penance and moral reckoning. Bearing in mind popular beliefs, the Romans believed that in the month of atonement Hades roamed among them, dealing out misery to unfortunate humanity, and so, apart from February having this particular "abnormality" in the days, the whole particular unlucky year.
"Leap years" were considered unlucky and marriages and the planting of vines had to be avoided, while when the Greeks were conquered by the Romans, this belief was also passed on to us. Among the traditions that accompany the leap day of February 29th is that on that day the tables are turned and women propose to men. In Greece, however, couples avoid getting married on this day, considering it to be unlucky.
How do we find which year is a "leap"
To find which year is a leap year, all we have to do is divide it by 4. If it divides exactly, it means that it is a leap year and that year has 366 days. The following leap years are:2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052, 2056, 2060, 2064, 2068, 2072, 2076, 2080, 2084, 2088, 2092, 2096, etc. 2