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闰年是怎么来的?

Why Do We Have Leap Years?

People have been keeping track of time,
大概从人类出现在地球上开始
pretty much since people were people.
我们就一直在记录时间
At first we just needed to have an idea of what season it was,
最初我们只是想知道当下是什么季节
and maybe what season was coming up next, and around when.
以及下一个季节是什么 何时会到来
But after the invention of agriculture,
但在农业出现之后
it started being important to keep track of each day of the year.
人们意识到 记录一年中的每一天也很重要
Once you start trying to count the days of the year though,
一旦开始尝试记录每一天
it doesn’t take long to notice a problem:
很快你会发现一个问题:
You just can’t make a consistent calendar
由于每年的天数并不是一个整数
with the same number of days every year,
所以我们不能制定一个不变的
because there aren’t a whole number of days in the year.
且每年天数都相同的日历
That is why today’s date exists!
于是有了今天的日期!
We have to add an extra day to the calendar every now and then and
我们有时需要在日历上多加一天
we do it on February 29th.
于是日历上有了2月29日
The main issue is that the Earth’s orbit and its rotation
有个主要问题是 地球的公转和自转之间
don’t have anything to do with each other.
没有任何关系
When our planet spins once around on its axis we call that a day
地球沿着自转轴转一圈的时间 我们称之为一天
and when it completes a full orbit of the sun, we call that a solar year.
地球绕太阳转一圈的时间 我们称之为一个回归年
Now it’d be nice if Earth always got back to the same place in its orbit
如果地球总是在完成一定数量的自转后
after a set number of complete rotations,
回到公转轨道上的同一个地方 那就好办了
which would be an exact number of days…
这样的话 自转的圈数就是一年的天数
but it doesn’t.
但事实并非如此
Earth orbits the sun once every 365.2425 rotations,
地球绕太阳一圈 期间会自转365.2425圈
so if your calendar has a whole number of days, like 365 or 366
所以 如果日历每年的天数是365或366天
than you’re counting either too few days or too many.
那你要么数少了 要么数多了
And if you’re counting wrong, then things like the solstices,
如果数错了 那么一年中最长和最短的一天
the longest and shortest days of the year,
通常发生在地球公转过程中固定的点上
which always happen at the same point in the Earth’s orbit,
也就是夏至和冬至 它们在日历上的位置
will move around the calendar.
将会有所变化
That makes it a little tricky to plan for events that you want to happen
当你要为每年都在同一天举办的活动做准备时
on the same day every year,
就很麻烦了
say a solstice celebration.
比如冬至日庆祝活动
And if that wasn’t complicated enough,
那样的日历还不够完善
a lot of ancient cultures,
于是许多文明古国的人
like the Babylonians, Chinese, and Romans,
如巴比伦人 古代中国人 以及古罗马人
used calendars based on the moon.
他们根据月亮来制定日历
But, the behavior of the moon, again,
但是 月亮的活动
has nothing to do with our rotation or our orbit.
与地球的自转和公转也没有任何关系
The moon goes through a little more than 12 cycles,
在地球绕着太阳转一圈的时间里
each a little more than 29 days, in the time that it takes
月球绕地球公转的圈数略多于12圈
for the Earth to go around the sun.
每转一圈需要29天多一点
And that means they had a similar problem:
那么这两种日历面临同样的问题:
12 lunar months a year is too few,
一年12个农历月太少了
but 13 lunar months in a year is too many.
但一年13个农历月又太多了
So most people using a lunar calendar would have 12 months most years but then,
所以多数人采用了每年有12个月的农历
they’d add an extra month every couple of years
此外 人们每隔几年会给农历加上一个月
to keep things, like harvest,
使收割作物等重要事件的日子
around roughly the same solar date.
每年几乎都在同一天
Then there were the Romans, always trying to keep things interesting.
然后是古罗马人 他们非常有意思
Instead of having a system in place,
他们没有制定合适的日历
for how often there should be an extra month,
至于每隔多少年应该增加一个月
they left it up to their highest religious authority:
他们把这个决定权交给了宗教的最高权威:
the Pontifex Maximus.
大祭司
Which kinda worked for a while,
这个传统延续了一段时间
at least until Julius Caesar came along.
至少延续到凯撒大帝的出现
The Romans thought adding those extra months was super bad luck,
罗马人认为增加额外的月份是个不祥之兆
so they didn’t want to do it while they were at war,
他们不想在打仗时加上额外的月份
and Julius was at war all the time.
而凯撒大帝一直都在打仗
So, the calendar got way off from where it should have been.
所以 古罗马的日历从此变得混乱不堪
Eventually, Caesar decided that the Romans should just use a brand new calendar,
最后 凯撒决定罗马人要使用一个全新的历法
that relied on a set system of,
该历法应该系统化
when and where to add extra days.
明确哪一年应该增加额外的天数
And that’s how we got the Julian Calendar,
因此就有了儒略历
which Western Europe and Christian churches
很长一段时间里 西欧和各基督教堂
used for a really long time.
都使用这种日历
Most Julian years had 365 days, but like we said earlier,
多数儒略年都有365天 但就像刚才说的
the year is about a quarter of a day longer than that,
一年有365又1/4天 所以每四年
so every 4th year got an extra 366th day.
就要加上1天 即那一年有366天
Seems like a good fix, but things are not that simple.
这看起来很合理 但事情没有那么简单
The four year system ends up slightly over-estimating
事实证明 这个每四年加一天的历法系统
the length of the year by about 10 minutes
使每年多出了10分钟
Something the designers of the Julian calendar knew about
关于这一点 儒略年的制定者是知道的
but they decided it wasn’t worth complicating the calendar over.
但他们认为没有必要把日历搞复杂了
It’s 10 minutes a year, what could go wrong?
不过是每年10分钟的误差 能怎样呢?
Well, 10 minutes a year, over a lot of years, can really add up.
一年10分钟 但多年后的误差就不小了
By the late 1500s,
到了16世纪末
around 1600 years after Caesar the calendar was
人们使用儒略历已有约1600年
about 13 days off from where it should have been.
此时日历已经比实际日期落后了13天
That’s when Pope Gregory XIII,
直到教皇格里高利十三世
the Pontifex Maximus of the Catholic Church at the time,
即当时天主教会的大祭司
decided that the Julian calendar needed an overhaul.
决定将儒略历进行一次大整改
So he put together the Gregorian calendar, the one that we still use today,
他将我们今天还在用的格里历和儒略历相结合
which is really just the Julian Calendar with a couple of changes.
实际上 儒略历和格里历只有几处不同
The Gregorian calendar’s new rules were:
格里历的新规则是:
Every 4 years add an extra day,
每4年要多加1天
except, don’t add it when the year is divisible by 100
如果那一年的年份能被100整除 则不加
except, actually, do add it if the year is divisible by 400.
但如果那年的年份能被400整除 则要加
So 1700, 1800, and 1900, weren’t leap years
所以1700年 1800年以及1900年不是闰年
because they were all divisible by 100, but not by 400.
因为它们能被100整除 但不能被400整除
The year 2000 was a leap year
2000年就是闰年
since 2000 is divisible by 400.
因为2000能被400整除
And, of course, 2016 is a leap year as well.
当然2016年也是闰年
If we were still using the Julian calendar,
如果我们仍然使用儒略历的话
2016 would still be a leap year
2016也属于闰年
But the calendar would now be behind by 16 days
而儒略历比实际日期落后了16天
So this video would have been uploaded
所以我们上传这个视频的日期
on February 13th, 2016
为2016年2月13日
not February 29th.
而不是2月29日
so it wouldn’t have made any sense.
这也没什么大不了的
But the universe is complicated and does not care about our calendars.
无论历法是否存在 宇宙依旧错综复杂
So the Gregorian calendar is still a little bit too long
格里历还是有些太长了
we will add a day about every 7,700 years,
所以我们每隔7700年会在日历上加上一天
but don’t hold your breath for a new calendar.
不要期待新历法的出现
The Gregorian calendar was only introduced when the Julian one
儒略历比实际日期落后13天时
was 13 days off from the true date.
人们才开始采用格里历
And that won’t happen to the Gregorian calendar
而格里历产生这样的误差
for another 100,000 years or so.
还要大约10万年
Thank you for watching this episode of SciShow,
感谢收看《科学秀》的视频
which was brought to you by our patrons on Patreon.
该视频由Patreon的赞助者们出资制作
If you want to help support the show,
如果你想支持我们的节目
you can go to: patreon.com/SciShow
你可以访问patreon.com/SciShow
We always very much appreciate that, it is the reason why we can do all this.
非常感谢大家 我们的节目离不开你们的支持
And if you want to keep getting smarter with us, as always,
如果你想要了解更多内容
go to YouTube.com/SciShow and subscribe.
请访问YouTube.com/SciShow 记得订阅

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视频概述

闰年是怎么来的呢,一起来了解一下吧。

听录译者

收集自网络

翻译译者

Spencer

审核员

审核员YQ

视频来源

https://www.youtube.com/watch?v=CXcN4K7LiB4

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