I have taken the title of this post from a famous film directed by William Wyler and released in 1946 (the year I was born). But in this post I am not going to deal with films, but with the different types of years.
Like the day, the year is a natural cycle, defined by the movement of the Earth around the sun. Unlike the day, which varies continuously and for which we must use the average duration, the solar year is fairly constant, as two different years are almost the same duration, although not exactly, so the concept of mean solar year is also used.
As with the hours, days and months, there are also several types of years, which differ slightly from each other, depending on the reference point considered (see the attached table).
