but it was actually the shortest year in decades.

但它實際上是幾十年來最短的一年。

In fact, it was 1.3 milliseconds shorter.

事實上，它縮短了1.3毫秒。

The planet is now spinning faster than it has any time in the last half-century,

地球現在的旋轉速度比過去半個世紀中的任何時候都快。

with 2020 containing 28 of the fastest days on record since 1960.

2020年包含了自1960年以來記錄中最快的28天。

And 2021 is expected to be even faster...

而2021年預計會更快...。

which has ignited a fiery debate about what we should do to keep the world on track.

這引發了一場關於我們應該怎樣做才能讓世界走上正軌的火熱辯論。

It may sound weird, but shifts in a planet's spin are actually normal.

這聽起來可能很奇怪，但行星自旋的轉變實際上是正常的。

Things like the pull of the moon,

像月亮的拉力這樣的事情。

jet stream winds,

噴氣流的風。

and plate tectonics all have an effect.

和板塊構造學都有影響。

Just like an ice skater draws in their arms to spin faster,

就像滑冰者為了更快地旋轉而抽出手臂一樣。

anything that moves mass closer to Earth's axis speeds up the planet's spin,

任何使品質靠近地球軸線的東西都會加速地球的旋轉。

making the days a few milliseconds shorter.

使得日子短了幾毫秒。

It doesn't seem like much, but these subtle changes in Earth's spin

這看起來並不多，但地球自旋的這些微妙變化

can cause major headaches for anyone trying to keep their clocks in sync.

可能會給任何試圖保持時鐘同步的人帶來很大的麻煩。

But first, here's a little context on how our timekeeping has evolved.

但首先，這裡有一個關於我們的記時法如何演變的小背景。

Before we had cell phones, computers, or GPS to tell time, we had the Sun.

在我們有手機、電腦或GPS來顯示時間之前，我們有太陽。

Ancient civilizations measured time using Earth's rotation relative to the sun

古代文明利用地球相對於太陽的旋轉來測量時間

with devices like sundials.

與日晷等設備。

We know this today as solar time.

我們今天知道這就是太陽時。

Around 150 AD, Ptolemy divided Earth's 360 degrees of latitude and longitude

公元150年左右，托勒密劃分了地球的360度經緯度

into 60 equal parts, into the “first minute”, and then again, into a “second minute”, the basis for a second.

抽成60個相等的部分，變成 "第一分鐘"，然後再變成 "第二分鐘"，這是一秒鐘的基礎。

The development of quartz clocks in the 1930's made timekeeping even more precise,

20世紀30年代，石英鐘的發展使計時更加精確。

and for the first time allowed us to measure variations in Earth's rotation.

並首次使我們能夠測量地球旋轉的變化。

Then atomic clocks revolutionized timekeeping.

然後，原子鐘徹底改變了計時方式。

In 1955, the National Physics Laboratory in England built the first accurate cesium clock,

1955年，英國的國家物理實驗室建造了第一個精確的銫鐘。

and twelve years later, the General Conference on Weights and Measures redefined the second,

而12年後，計量大會重新定義了第二種。

based on this crazy number of oscillations of a cesium atom.

基於一個銫原子的這種瘋狂的振盪次數。

This ultra-precise definition of a second is the foundation of International Atomic Time,

這種對一秒鐘的超精確定義是國際原子時的基礎。

the average of hundreds of atomic clocks worldwide, making it our most accurate time keeper.

是全世界數百個原子鐘的平均數，使其成為我們最精確的時間記錄器。

Atomic time can measure the spin of the planet down to the millisecond.

原子時間可以測量行星的旋轉，精確到毫秒。

But the increase in accuracy comes with a downside.

但是準確度的提高也有一個缺點。

Since atomic time ticks away at an incredibly constant rate,

由於原子時間以驚人的恆定速度流逝。

it doesn't slow-down or speed-up with the spin of the Earth.

它不會隨著地球的旋轉而減慢或加快。

So, over the years atomic time has slowly drifted out of sync with the fluctuations of the planet.

是以，多年來，原子時間已經慢慢地與地球的波動不同步了。

Whenever the difference between solar time and atomic time

每當太陽時和原子時之間的差異

threatens to exceed 0.9 seconds,

有可能超過0.9秒。

a leap second gets added to Coordinated Universal Time to make up for the difference.

閏秒被添加到協調世界時中，以彌補差異。

UTC is kept using atomic clocks, but with all those leap seconds added in.

UTC是使用原子鐘來保持的，但加入了所有這些閏秒。

To date, we've added 27 leap seconds since 1972.

到目前為止，自1972年以來，我們已經增加了27個閏秒。

The extra second gets squeezed in at midnight UTC.

多出的一秒在UTC午夜時分被擠了進去。

Which is where the heated debate comes in.

這就是激烈辯論的地方。

Those who want to abolish the leap second say that in addition to being cumbersome,

那些想廢除閏秒的人說，除了繁瑣之外。

it would take 5,000 years to notice even a one hour difference

即使是一小時的差異，也需要5000年才能注意到

between Earth's rotation and the atomic clock.

地球的自轉和原子鐘之間的關係。

And when one was added in 2012,

而當2012年增加了一個。

the reservation system used by Qantas airlines collapsed,

澳大利亞航空公司使用的預訂系統崩潰。

and several websites including Reddit, Mozilla, and Gawker,

和一些網站，包括Reddit、Mozilla和Gawker。

crashed when their systems failed to handle the extra second.

當他們的系統無法處理額外的一秒鐘時，就會崩潰。

However, those in favor of the leap second argue that the technical issues are overblown.

然而，支持閏秒的人認為，技術問題被誇大了。

Just a few years later in 2015, another second was added—

就在幾年後的2015年，又增加了第二個--

and there were only a few minor hiccups.

而且只出現了一些小插曲。

The standoff is real and countries have already taken sides,

對峙是真實的，各國已經站在了一邊。

with the U.K. and Russia in favor of keeping leap seconds,

與英國和俄羅斯一樣，贊成保留閏秒。

and countries like the U.S. and China advocating their drop.

以及像美國和中國這樣的國家主張他們放棄。

At the 2015 World Radiocommunication Conference held by the U.N.,

在聯合國舉行的2015年世界無線電通信大會上。

countries couldn't come to an agreement,

各國無法達成協議。

so they decided to put off their decision till their next conference in 2023.

所以他們決定將決定延後到2023年的下一次會議。

But no matter how long they debate, the Earth will continue to spin.

但無論他們辯論多久，地球都會繼續旋轉。

And it's up to the International Earth Rotation and Reference Systems Service, or IERS,

而這取決於國際地球自轉和參考系統服務，或IERS。

to determine if a year needs a leap second or not.

來確定一個年份是否需要一個閏秒。

Last year Earth's rotation was fast,

去年，地球的自轉速度很快。

and didn't need a leap second—at least, in the traditional sense.

而且不需要躍進的第二步--至少，在傳統意義上。

Because it was spinning so fast,

因為它轉得太快了。

the average day was estimated to be .05 milliseconds shorter than a typical 24-hour period.

據估計，平均每天比典型的24小時內短0.05毫秒。

Because of this, the group considered something they never had before: adding a negative leap second.

正因為如此，該小組考慮了他們以前從未考慮過的問題：增加一個負的閏秒。

Instead of gaining a second, we would lose one.

我們非但沒有獲得一秒鐘，反而會失去一秒鐘。

And this year, scientists expect it to be even speedier!

而在今年，科學家們預計它的速度會更快!

While the group ultimately decided not to add this negative leap second last year,

雖然該小組去年最終決定不增加這個負數的閏年。

it's possible that they might have to when they meet again this June.

他們有可能在今年6月再次見面時不得不這樣做。

All I know is when they finally make a decision,

我所知道的是當他們最終做出決定時。

we'll all be saying, it's about time.

我們都會說，是時候了。

We talked about removing a second from our clocks, but what about time itself?

我們談到了從我們的時鐘中刪除一秒，但時間本身呢？

Can it ever run backward?

它能不能向後運行？

Check out this video from Julian that explains how time might not reverse like physicists thought.

看看這個來自朱利安的視頻，它解釋了時間可能不像物理學家所想的那樣逆轉。

Have some cool science you'd like to see us cover?

有一些你想看到我們報道的很酷的科學嗎？

Let us know in the comments below and as always, thanks for watching Seeker.

請在下面的評論中告訴我們，並一如既往地感謝觀看《探索者》。