A year is a period of time that is often measured as 365 days, 5 hours, 48 minutes and 45 seconds. This isn’t however the only definition for the word “year”. In fact, there are several different ways to look at how long an Earth year lasts.
First let’s go over the most common type of year: a calendar year. A calendar year begins on January 1st and ends on December 31st. There are twelve months in a calendar year – January, February, March etc – and each month has a set number of days – the number of days in a month changes from month to month – which adds up to just about three hundred sixty five days per year. Because there are seven days in a week, a common year is made up of exactly 52 weeks.
The second type of year we need to look at is the sidereal year. A sidereal year lasts for about 365 days, six hours and nine minutes – slightly longer than a standard calendar year. A sidereal day last just as long as a regular day except for one difference: it begins when the stars are aligned with the same location from which they were aligned six months prior. This means that there are 366 sidereal days in a single Earth orbit around the Sun – compared to only 365 solar days per orbital period – making each star appear to move a little bit westward on the sky every single day before returning back into its original position six months later.
The third type of year we need to look at is the tropical year. A tropical year is a unique type of year in which each new year begins on the vernal equinox – the day when the Sun crosses over Earth’s equator, making night and day exactly equal length everywhere on Earth. It’s no coincidence that this also marks where two hemispheres once more become directly aligned with the Sun, resulting in summer beginning in one hemisphere and winter beginning in another. In essence, a tropical year lasts for about 365 days, five hours 48 minutes and 46 seconds, only four minutes shorter than a calendar year.
Another major difference between a common or standard calendar years and other types of years is the fact that one Earth orbit around the Sun doesn’t exactly equal 365 days. This might be an inconvenient truth for astronomers, but it’s a necessary inconvenience because math would be too easy to work with if every orbital period lasted exactly 365 days.
That said, there are other (less common) ways to look at How Many Weeks In A Year lasts, including anomalistic year which results in about 365 days, six hours and five minutes; synodic year resulting in about 365 days, 10 hours and 49 minutes; draconic year resulting in about 366 days, four hours and 49 minutes (the time between two successive vernal equinoxes); and even a sidereal-year lasting about 364 days, six hours and nine minutes.
So, in conclusion, an Earth year lasts for anywhere between 365 days, 6 hours and 9 minutes to 366 days, four hours and 49 minutes; depending on whether or not you want to go with a common or sidereal year. a set relation to every single calendar. Every time someone says “a week”, they’re automatically assuming it matches up with one certain type of year – if not for this universal base assumption then we would all be using totally different weeks! So although weeks might seem very simple at first glance