This year has been the earliest spring season since 1896

If you Google " First day of Spring " (the first day of Spring), the result will be March 20. But don't believe it!

With so many people in America, the first day of spring actually takes place on March 19.

And so, this year marks the earliest spring in history since 1896.

This happened because 2000 was a leap year, which was quite unusual when years like 1700, 1800, and 1900 were not leap years.

Don't worry, there's no hand of any force outside nature. It is simply a consequence of our imperfect Gregorius Calendar system, which is not exactly the Earth's rotation cycle every year.

Since ancient times, our ancient ancestors have decided that spring will officially begin when the sun shines directly on the equator (illustration below). As a result, the first day of spring will be called spring equinox .

The first day of spring is when the sun shines directly on the equator.

However, there is a problem with setting the season based on Earth's movement in the universe, here is the time for the Earth to complete an orbit around the sun - which is not exactly 365 days.

In fact, it will take 365 days, 5 hours, 48 ​​minutes, and 45 seconds.

However, the Gregorius calendar indicates a year of 365 days in length - no more and no less. With leap years, one year will be 366 days.

The leap year is a great way to handle this discrepancy and keep our calendar, as well as the seasons, under control. Without a leap year, our calendar will be much earlier. In only 100 years our calendar will deviate from 24 days compared to reality.

Special exception

The first day of spring in this year is March 19.

But having a leap year every four years cannot be solved thoroughly. That is why there will be two special exceptions:

1. There will be no leap year at the turn of the century. The years 1700, 1800, and 1900 will not be a leap year, even if they still fall into a four-year cycle.

2. Unless the turn of the century is divisible by 400. That's why the year 2000 was a leap year.

" Our calendar system is set on a 400-year cycle so that it can solve all the remaining small parts when the Earth does not rotate within 365 and a quarter of the day, " astronomers said. Bob Berman - executive of the Overlook Observatory in New York and owns a huge book that records tens of thousands of days of spring and the past and future.

" This works ," explains Berman, " making the leap year reset itself so that the points and points will all happen [on schedule]. "

Berman is a frequent guest at a program organized by Slooh, which is a series of observatories around the world that stream live astronomical events.

The obvious difference with the 21st century is that 2000 was a leap year. Although this does not affect our daily life, it still makes a difference:

" Instead of everything being reset so that every day the points and points are back to their usual days . but this doesn't happen, " said Berman.

As a result, the first day of spring will be moved to an earlier time during this century.

This year, spring equinox officially begins at 4.30 on March 20 in the UT time zone, meaning it will take place at 11:30 on March 20 in Vietnam time and 9.30 pm on March 19 according to PT time zone.

Before the beginning of the year 2100, it will not be just in the United States - anyone on this planet will experience spring equinox on March 19.

Until 2300, we will return to normal and most spring days will fall again on March 21.

" These are all in the plan to keep the date from being deviated too far from reality ," Berman said. " And thanks to this, it really keeps everything accurate with a deviation of about a day for 400 years. It's really impressive. "