Please explain my confused me like I’m 5 (0r 4 or 6).
It depends which calendar you use! Every calendar picks a basically arbitrary system to uniquely identify each year, and in some of them “year 0” doesn’t refer to any year.
The Gregorian, for example, goes directly from 1 BC to 1 AD, since 1 BC is “the first year before Christ” and 1 AD is “the first in the years of our lord.” This doesn’t make much mathematical sense, but it’s not like there was a year that didn’t happen–they just called one year 1 BC, and the next year 1 AD.
ISO 8601 is based on the Gregorian calendar, but it includes a year 0. 1 BC is the same year as +0000; thus 2 BC is -0001, and all earlier years are likewise offset by 1 between the two calendars.
If ISO says there was a year 0, there was. There’s only one thing better than perfect : standardized !
Yes. They skipped right over. It confused many people at the time: a whole year of their lives, gone. Many centuries later when zero was invented, an explanation was finally offered as to why that happened.
Serious answer about what the year would have been in 1 AD, according to 63-year-old Emporer Augustus: DCCLIV 754 Ab Urbe Condita
That means “from the founding of the city” - they based their calendar on the mythical founding of Rome, as calculated by Verro, who himself was not long dead at that point. Before that, they just counted the years of each person’s reign Japanese-style. Probably other people in the ancient world had older calendars.
When you consider the time as a number line, years are not points at integers (which would in some way warrant a year 0), but rather periods between them. Year 1 is the period between 0 and 1, and before that was -1 to 0, or year -1. There is no year 0, because there isn’t anything between 0 and 0
That makes sense, but trying to square that off with the idea that the year 2000 is the start of the 21st century is hurting my head.
If year 1 is the 1st year, then surely the first year of the 21st century should be 2001?
The enumeration on the losing side of that debate is probably correct. But as a person who was in my early 20s in 2000, I’d like to offer what I will characterize as The Historical Context and Definitive Conclusion to This Debate.
No one actually gave a shit about that debate. Sure, it came up, but it did not alter anyone’s party planning. We weren’t actually celebrating the changing of the millennium, we were celebrating because we had a permission slip to do so. Any attempt to withdraw that permission was unwelcome.
In Paris on December 31st, 1999, at around 11pm local time, someone threw themselves in front of a metro. The trains were free that night (because it was the 100 year anniversary of their opening iirc), but because of that suicide, at least one of the train lines was substantially delayed. The streets from the center of the city to the north side were crowded well toward dawn as everyone chose to walk home instead of wait indefinitely in a stinky train station.
That person, who chose to end their life on the tracks that night, holds the core truth of the debate within his death: it’s a ridiculous debate and those who would fight for it should just stay the hell home and let the rest of us drink a lot and dance.
Ohh, nice one!
The first convention is common in English-speaking countries, but the latter is favoured in, for example, Sweden (tvåtusentalet, which translates literally as the two thousands period).
I’m not sure that’s entirely true, most people in English speaking countries (and the world over) celebrated the millenium at the beginning of the year 2000.
the idea that the year 2000 is the start of the 21st century is hurting my head.
That may be because it is not. The first century was years 1 to 100. The second was 101 to 200. The 21st is therefore 2001 to 2100.
What you’re probably referring to is the “cultural century” which was considered to have started when the lead digit changed from 1 to 2. The same thing happened quite recently when some people argued 2020 was the start of a new decade (again, it wasn’t)
I hate it when people say it wasnt the start of a new decade, it’s a shit argument, why does it matter what the first year was, 2014 - 2024 is also a decade, and 2pm aest September 22nd 2024 will also be the start of a new decade. There is nothing wrong with saying 2020 was the start of a new decade. (again, it was)
This explanation is unclear to me. Why do we choose the later of the two endpoints of the year for (0, 1) but the earlier of the two for (-1, 0)?
The language is rooted in the same logic as people. Your first year was between the ages of 0 and 1. The first year before you were born is between -1 and 0. There is no 0th year because 0 is a point in time and not a range in time.
Your explanation works equally well for any integer though. You could say the same of 1.
I think you’re saying that it’s a fencepost issue. But even for personal ages this doesn’t check out: for a year after you are born, your age is “0.” A one-year-old baby is in the following year.
Absolute value. Both systems count time from the same epoch, or zero point.
One year before the epoch is 1 January 1BCE One year after the epoch is 31 December, 1CE.
Half a year before the epoch (-0.5 years) is June 30, 1BCE. Half a year after the epoch (0.5 years) is July 1st, 1CE. These dates occur within the first year before the epoch, and the first year after the epoch, respectively.
Remember originally that -1 was 1 BC, meaning 1 year before the birth of christ. The negative numbers are measuring the distance away from 0.
Edit: in the positive direction, the 1 was 1 AD, meaning the first year of our lord. Just like when talking about the reign of kings/queens, the first year of their reign is 1 and the 14th year that they reigned is 14. I believe the timekeeping for Ages in LOTR may also be similar.
If we were starting from scratch, it would probably be better to go with two year zeroes, so it would fit normally into positional number systems, and then you could even talk about 0.5AD for the relevant summer.
Unfortunately, positional numbering wouldn’t be invented in the old world until hundreds of years after the Christian calendar.
The only positional numbering system I use daily (base 10) has only one zero. What system are you talking about?
Oh really? What do -0.25 and 0.25 both start with, and round to?
A reminder to read the original reply that started this thread. There’s two “zero-areas” between the one points and the zero point.
Years exist. We decide what to call them. You and I agree to call this year 2024, but that’s only an agreement. Some people call this year 5784.
We call the system we use “The Gregorian Calendar”, because of a Pope named Gregory. That system is mostly the same as “The Julian Calendar”, with some important changes to make the calendar match the changing of the seasons better. In the Julian calendar, they decided to count the years starting from when they thought Jesus was born. They chose his birth year to be “The first year of our Lord”. We call that “year 1” for short.
The people who created that system (the Julian Calendar) didn’t understand 0. The year before “The first year of our Lord” was called “The first year before the birth of Christ”. We now call these “AD 1” (“anno domini”, because Latin) and “1 BC” (“before Christ”). Since they didn’t understand 0, they didn’t call any year “0”. We have kept the tradition, because reasons.
Some other systems have relabeled the year before “AD 1” as year 0, but that’s not how the Gregorian Calendar works, and that’s the calendar that you and I have been taught to use.
“They,” i.e. the catholic church, or whoever was tasked with coming up with a calendar, absolutely understood the concept of zero in the 1500’s. Yes, Zero took a bit longer to formalize and enter the zeitgeist of the public consciousness, but this myth of zero being some kind of unknowable thing for thousands of millennia is naive.
I’d go so far as to say that a year zero in a calendar is useless. There should be a starting point of course, but calling it yero zero instead of year 1 is dumb.
By that part, I was referring to the people establishing the Julian Calendar, not the Gregorian. I’ve edited my comment to clarify that.
But you are missing the point,. There is no reason to ever start a calendar at year zero. The starting point can be zero, fine, but once the first day goes by, you are in the first day of year 1, not year zero and that is logical and has nothing to do with smart astronomers etc, “not understanding the number zero.”
At this point I’d say the only person who doesn’t understand zero is you.
https://en.wikipedia.org/wiki/Year_zero
The year of Jesus’ supposed birth was counted as year 1 AD/CE. The year before that is considered year 1 BC/BCE. It’s worth noting that the concept of zero didn’t yet exist back then. https://en.wikipedia.org/wiki/0#History
Probably worth noting that the Gregorian Calendar was an invention of the 16th Century. It was invented to deal with the problems of the Julian Calendar and the creators would have had a firm understanding of the concept of zero. The AD/BC split was all about the assumed year of the birth of Jesus of Nazareth (according to Christian mythology). The year of his birth was set as the first year Anno Domini or “The year of the Lord”. Or the first year where Jesus was kicking about. The year prior to that would therefore be the first year before “Before Christ” was alive, and therefore the year 1 BC.
Especially weird considering that Christmas has been set to December for a long time, so 98% of year 1 AD was actually before the ostensible birth of Christ (I know that scholars now think he was born in April or something, but they probably didn’t always)
Ultimately, they had to set the calendar’s dates based on something. Given the vast hold on Europe which Christianity had at the time, it’s not surprising that the starting date was based on such an important event in the mythology. However, trying to deviate too far from the currently understood order (the Julian Calendar) was likely to end in failure. So, they could either fight the tide of history or just accept a logical oddity. Given all the other logical oddities one must accept for supernatural belief, who’s going to complain about having a holy reason to eat, drink and be merry during one of the most terrible parts of the year?
