February 29 is a sometimes and sometimes not on the calendar. Because the Earth's orbital period is not an integer number of days, in order to reduce the calendar error, humans have to use leap years, that is, every few years to increase by one day, that is, February 29. In 1582, the Gregorian calendar formally established the rules of one leap in four years, no leap in one hundred years, and four hundred leaps. In this episode, Ding anchor starred in the unusual day of February 29.
Today's program lasts about 22 minutes and is suitable for parents and children on the way to school or before going to bed.
February 29 in the leap calendar
This extra day is due to leap years. Since the Earth's orbital cycle is not an integer number of days, in order to make up for the inaccuracy of 365 days a year, human beings make up for one day at intervals, which is a leap year. And this extra day was made up for in February.
Earth's orbital cycle
The earth's cycle of one full circle around the sun is 365.242188 days, which is an error with the integer days on the calendar. Humans have long discovered that when using a calendar of 365 days a year, there is a large deviation shortly after. So people started making up one day every four years on the calendar, which is a leap year.
The Shang Shu Yao Dian records the ancient Chinese leap days
In 46 BC, Caesar promulgated the Julian calendar. Julius is the old translation of Julius Caesar. In the Julian calendar, the 365 days of the year are divided into 12 months, and the size of the month is set, of which 2 months are small months, only 29 days. When a leap year is encountered, it is added another day in February. However, this leap method was still not precise enough, and by the time of Caesar's successor, Octavian, the leap method of adding 1 day every 4 years was officially determined. Octavian also named the month of his birth, August, after his title August, and adjusted August to the Great Moon, the same as July, when Caesar was born. In this way, August borrowed 1 day from February, and February became only 28 days.
Ancient Roman calendar
Since the Earth's orbital cycle is not exactly 0.25 days per year, there are still errors in the leap every four years method. By the 16th century, this error was so great that it had to reissue a calendar. In 1582, the then Pope Gregory promulgated a new calendar, also known as the Gregorian calendar. This calendar formalizes the method of addition and subtraction on February 29, that is, the leap year rule: one leap year in four years, no leap in 100 years, and 400 leap years.
Gregory calendar
Because of this seemingly complicated leap law, February 29 became a calendar day. The first to be affected are those born on this day. Rossini, the Italian musician who wrote the opera The Barber of Seville, was born on this day in 1792. For people born today, birthdays are not every year.
Rossini's birthday is February 29
This special day has also produced some special anniversaries. On 29 February 1288, queen Margaret of Scotland issued a decree declaring it "Women's Courtship Day". On this uncommon day, women can make unusual moves – actively courting men, and the decree also stipulates that men who do not accept courtship must accept punishment, pay 1 pound ransom or give silk clothes to each other.
Queen Margaret of Scotland
In 2008, the day began as World Rare Disease Day to support people with rare diseases. For example, albinism, hemophilia, although the incidence of these diseases is not high, it is not very common in life, but the sick population is very worthy of our attention and support.
Rare diseases
February 29 on the calendar sometimes, sometimes not, there will be some misunderstandings in life. When people agree on something to do on February 29, it can be considered a joke. The 2016 Oscars were awarded on February 29, and DiCaprio, who finally won the award after years of running with him, was also ridiculed that winning the award on this day may be a joke.
DiCaprio won the Oscar on Feb. 29
In this issue of the role play, Ding anchor starred in the occasional day of February 29, asking why Pope Gregory had set him like this.
About Chat Hundred
Talking about Encyclopedia is an encyclopedic audio chat program between Tintin and Ding Dad.
Tintin, a young boy after 10, dreams of becoming a scientist and loves to read various encyclopedias.
Ding Dad, a post-70s science and engineering man, also has a Wenqing heart, can solve the equations, write articles.
The curious Tintin and the equally curious Ding Dad like to use playful language and their respective perspectives to talk about the past, present and future of our world. One day, the father and son began recording the conversation into audio.
Every chat is a knowledge adventure and a re-learning. Tintin began to talk about the high-dimensional space in the black hole, lamenting that Mozart and Salieri were in love and killing each other... Ding Dad also began to nibble on the original "Theory of Relativity", and the basic music theory knowledge of the evil supplement...
Today, the father and son have talked about "Talking About Today" dedicated to history for 365 issues a year, as well as "Talking about An Art" dedicated to famous paintings, "Memorizing An Ancient Poem" of ancient poetry allusions, and Tintin's travelogues around the world, and so on...
The world deserves our good attention, deserves our good talk, and deserves your good listening.
How to listen to 1 year 365 days of chat today?
Pay attention to the "Chat Encyclopedia" public account, enter the menu, select "Talk Today", and browse by month