What Decade Is It?

[dar512]

Originally Posted by skysidhe

Your tenth birthday is the end of your 9th year. You begin a 10th year.

That doesn't sound right. Your first birthday is the end of your first year, right?

How many birthdays do people have on average? Trick question. Just one. Technically the rest are anniversaries of your birthday.

[Radar]

Originally Posted by Spexxvet

If:

Then 1899 to 1900 was the last year of the 19th century. It ended, technically, on Dec. 31, 1899.

Not:

Actually, the 19th century ended on December 31, 1900 at midnight.

[Radar]

Originally Posted by skysidhe

Your tenth birthday is the end of your 9th year. You begin a 10th year.

A human lifespan isn't counted in the same way as the earths.
It has leap years and leap seconds.




18th century

1701-1800


19th century
1801-1900


The Twentieth Century of the Common Era began on January 1, 1901 and ended on December 31, 2000. according to the Gregorian calendar, (2000 was the first century leap year since 1600).

In the Gregorian calendar, a Century leap year is a year that is exactly divisible by 400 (and, thus, as with every other leap year, qualifies for the intercalation of February 29). The years 1600 and 2000, for example, were century leap years; the century years of 1700, 1800, and 1900 were not century leap years. The next century leap year will occur in 2400. Century leap years always start on a Saturday, and the February 29 intercalation of such years is always a Tuesday.
The century year "divisible by 400" rule of the Gregorian calendar was considered an improvement over the previously utilized Julian calendar which had provided for a leap year every four years; this practice resulted, over the centuries, in too many leap days being added to the calendar and placing it out of step with the astronomical seasons.

Exactly.

[wolf]

This is all very like the origin 1/origin 0 conversation that we have everytime we try to figure out how old Forks is.

[glatt]

How hard is it to count? Apparently it's fairly hard.

[wolf]

You have no idea.

[Happy Monkey]

Originally Posted by skysidhe

Your tenth birthday is the end of your 9th year. You begin a 10th year.

Originally Posted by dar512

That doesn't sound right. Your first birthday is the end of your first year, right?

Correct. Your tenth birthday is at the end of the year you are nine, which is the tenth year you have been alive.

[skysidhe]

Counting all of the decades confused me and since Happy Monkey is the most logical poster I can see I knew if you ( HM) said it was this and not that ,it probably was so, so I counted again and you are right.
It is the beginning of your 10th year not 9th year.

But the centuries and decades are adjusted for leap years and leap seconds to keep up with the way the planet(s) are rotating?

[Happy Monkey]

Years are of varying lengths, in order to keep the average length as close as possible to an astronomical year. Centuries and decades are defined by years, not days or seconds, so they don't really need to be adjusted, as such, as long as you don't expect them to be the same number of seconds long.It's similar to the fact that a baby turning six months old will not necessarily be twice as many days old as one turning three months old, but they are twice as many months old.

[Urbane Guerrilla]

Jim's count is off by one year. Owing to there not having been a Year Zero (imagine what the calendars would have looked like) for the BC-AD calculations were done in Roman numerals and hence no notation for zero in the first place (even worse for the calendars), the -10 years are the final years of a given decade, the -1 following years the first of the next. Been that way at least since Jesus was a toddler, what with that 4BC-1AD calculation slop (an arithmetical error in the calculation).

Yes, Skysidhe. Planet, singular; Mama Earth. It was either make Earth's rotation the standard, or the timekeeping of a cesium clock, which is precise enough to develop a measurable discrepancy with an earthly wibblewobble. Unfortunately, that would just produce a smaller-scale edition of the kind of discrepancy that got the Julian calendar dumped for the Gregorian over various parts of the globe in various times from the eighteenth through the early twentieth centuries. They had to do a two-week leap, or even more.

So to keep our clocks lined up with the stars, the sun (4 min difference per day, but it recycles) and the world, we have the world and its occasional jiggles as the standard, and reset the cesium clocks to that.