What is a leap year? Why will we have February 29th in 2024?

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Every four years (with some exceptions), the month of February gains an extra day. This is due to the time it takes the Earth to go around the Sun, which is about 365 days and, get this, 6 hours. Understand why leap years exist, like 2024 At the age of 20, Arthur Oliveira, from São Paulo, heard from his friends that he was actually 5 years old. 🤔 And it wasn’t because of his appearance (or supposed childishness) — it’s just that the young man was born on February 29th, a date that only exists on the calendar every four years (apart from a few exceptions, which you’ll understand below). “I grew up celebrating on the 28th all my life,” he says. In 2024, the party will be able to take place on the right day, as it is a leap year (i.e., we will have 02/29 on the agenda)! Why did the dictator Julius Caesar, who ruled Rome from 49 to 44 BC, decide to extend this month from time to time? See below. 🌍Why does a leap year exist? What defines a year, in our civil calendar, is the time it takes for the Earth to go around the Sun (translation movement). However, this process, in the solar calendar, does not take exactly 365 days — there is rounding to make the calculations easier. In fact, according to astronomers, our planet takes around 365 days and 6 hours to complete the “route”. If we add these 6 hours that are “left over” each year, in 4 years, we will have 24 extra hours (6 + 6 + 6 + 6 = 24). In other words: one more day, set on February 29th. 🌍What would be the problem with there not being 02/29 in leap years? It may seem silly, but not compensating every four years for these “overtimes” would even mess up our economy. “There would be a disconnection between the dates of the calendar year and the seasons of the year”, explains Rui Calares, coordinator of the Cursinho da Poli (SP) and geography teacher. “This would disrupt agriculture, for example, and planting and harvesting dates.” Two factors determine whether it is spring, summer, autumn or winter in a given hemisphere: the Earth’s tilt axis and the planet’s position in relation to the Sun. If the 6 “extra” hours each year were not corrected, our calendar would start to change. lag behind the four seasons. “We would be left behind in relation to nature. After some time, spring would only begin in December in the southern hemisphere, for example”, says Thiago Rigel, astronomy professor at Curso Stage (SP). 🌍How do I know if a year is a leap year or not? The basic rule is: leap years are divisible by 4 (that is, numbers that, when divided by 4, give integer results, without decimal places). This is the case of 2024 -> 2024 ÷ 4 = 56 -> integer. ❗But years that end in “00” need more attention. If it ends in 00 and is divisible by 400, it is a leap year. Example: 2000 (2000 ÷ 4 = 5 -> integer). If it ends in 00 and is not divisible by 400, it is NOT a leap year. It’s an exception! Example: 1900 (1900 ÷ 4 = 4.75 -> not a whole number). ➡️Why? The Earth’s translation time is not exactly 365 days and 6 hours. In fact, the planet takes about 365 days, 5 hours, 48 ​​minutes and 48 seconds to go around the Sun (difference of 11 minutes and 12 seconds). And then, over time, these 11 minutes and 12 seconds “borrowed” accumulate and need to be discounted from the calendar. That’s why, when the number ends in “00” and is not divisible by 400, the year is no longer a leap year and has the usual 28 days in February. The last time this happened was in 1900, and the next time will be in 2100. 🌍Who invented leap years? Reconciling the lunar calendar (which took the phases of the Moon into account) with the solar calendar was already an old mission. “In Egypt, for example, people knew that when a star ‘X’ appeared in the sky, the river would be full and it would be a good time for plantations. But this happened, let’s assume, on September 1st one year. Then, it fell on September 2, 3 or 4. They realized that they needed to make a correction to the calendar, to synchronize astronomical phenomena with human life”, explains astronomer Rigel. This is how, some time later, leap years were incorporated by Emperor Julius Caesar, who ruled Rome from 49 to 44 BC. “The Julian calendar promoted a major reform. It created a year of 365 days/12 months and added a day every 4 years”, says Thomas Wisiak, history teacher at the Stage Course. Our current organization of time is based on the Gregorian calendar, which replaced the Julian in 1582, on the initiative of Pope Gregory XIII. The new version was more accurate and corrected delays in relation to the seasons. That’s when that little rule about dividing by 400 came up, which g1 explained above. videos

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