起床 5：25
天気 曇り夕方から雨（起床時の気温 5℃）
日の出 6：12／日の入り 17：36
Today, I went to the hospital in the morning to undergo hyperbaric oxygen treatment（Part ）.
In the afternoon, I went to my part-time job.
Also, I went to cram school in the evening.
At the cram school, I gave congratulations to the child who passed the high school entrance exam.
I decided to include an article about
``Kumiko Torikai,'' a teacher who gave me an
English radio course when I was taking my
university entrance exams. Chocolate
I received on Valentine's Day (Part 1)
"Leap" in leap year is a word that is not used
on a daily basis. "Uruu" is written as "閏" in
Kanji. ``Leap'' means ``a year with more months
than a normal year.'' Years like 2020 are called
leap years, and February 29th, which does
not occur in normal years, is a leap day. Leap
year means "leap year" or "intercalary
year" in English.
In many lunar-solar calendars, a leap month is added approximately once every three years to make the total 13 months, so that the calendar dates and seasons do not deviate. In addition to leap years and leap months, there is also the word leap second. This is related to the fact that a day is 86,400 seconds long. The length of one second is defined by the vibrations of atoms, but the rotation speed of the Earth is not constant, and there may be a deviation from the definition of time due to the vibrations of atoms. Therefore, leap seconds are used to compensate for the difference between the world standard Coordinated Universal Time and universal time (astronomical time) due to the rotation of the Earth.
Leap seconds have been observed 27 times since 1972. It was most recently applied on January 1, 2017. In Japan, 8:59:60 was inserted between 8:59:59 and 9:00:00 on January 1, 2017. Google and others gradually adjusted the difference over 20 hours by slowing down the speed by 0.0014% from 10 hours before to 10 hours after. In most cases, leap seconds can be accommodated by adding or subtracting one second.
Because the Earth's rotation varies irregularly, it is difficult to predict the need for leap seconds. There is also an opinion that leap seconds should be abolished due to the risks associated with the system.
