They were vast improvement over the dangerous tradition of putting actual flaming candles in a very, very dry tree, but in doing so he also invented a new kind of headache ...

相較於將燃燒的蠟燭插在乾燥的樹上這危險的傳統，實屬是一大進步，但這樣又產生了一個令人頭痛的問題...

How… how did this happen? I was so careful last year…

呃...怎麼會這樣。我去年很小心的阿...

Scientists have spent a lot of time thinking about how things get tangled.

科學家花了很長時間去想要怎麼讓所有事情不再糾結。

And it turns out it's just the rules of the universe.

而這就是宇宙運行的規則。

In 2007, physicists showed for any cord longer than about 2 meters, knots aren't rare, they're almost guaranteed to happen.

2007年，物理學家揭示了任何超過2公尺的線是非常容易打結的，這幾乎是保證會發生的事。

Though the math is a little complex, but think of it as the most frustrating example of entropy you've ever encountered:

數學式有點複雜，，但想想，這裡有個你一定遇過最令人感到挫折的例子：

There's always only one way for a string of lights to be untangled, but with a few turns, there's billions, or trillions or more ways for them to get tied up.

只有走直線可以讓一條燈泡線不打結，而只要幾個彎就會有幾十億或是幾兆，甚至更多的可能性會讓線糾纏在一起。

Stupid Edison. I bet Tesla would have figured this out.

真是蠢的愛迪生。但我相信特斯拉會解決這問題的。

On Christmas Eve, 1968, the astronauts of Apollo 8 became the first humans to orbit another world.

在1968年的聖誕夜裡，阿波羅八號的太空人們，也是人類首次，在另一個世界裡運行。

The next day, on Christmas, they radioed back a very important observation from their vantage point above Earth.

隔天，也就是聖誕節，因他們有比在地球上有更好的視野，所以他們用無線電發回一個他們觀察到的重要訊息。

"Roger, please be informed there is a Santa Claus"

「請注意，我們看到了聖誕老人」

Well, if NASA said it, it's gotta be true!

好吧，既然NASA都這樣說了，那應該是真的吧！

According to reliable sources, Santa's sleigh is pulled by a team of reindeer, the most famous one being, of course, Rudolph.

根據可靠消息指出，聖誕老人的雪橇是由一群馴鹿拉著走的，而其中最有名的一隻，當然就是魯道夫拉。

But Rosie might be a more appropriate name.

但也許蘿西才是更適合的名字。

Male reindeer, and caribou, they're the same species, shed their antlers during the winter, and that means Santa's reindeer are all female.

雄性馴鹿，也就是北美馴鹿。在冬天他們的鹿茸會脫落，這表示聖誕老人馴鹿都是雌性的。

Reindeer vision is uniquely adapted for Santa's nighttime flight.

而馴鹿的視覺的確是很特別而能夠適應聖誕老的夜間的飛行。

To cope with the months of darkness at northern latitudes, the inside of a reindeer's eyes change from gold-colored in summer to blue in winter, which scatters more light onto their retina.

為了適應高緯度的黑暗，在夏天，馴鹿的眼睛內部是金色的，而當冬天來到，則會變藍，這樣可以讓視網膜聚集更多的光線。

So how do they fly? Would you believe that reindeer are buoyant?

至於他們怎麼飛行？你相信馴鹿是有浮力的嗎？

(singing) Reindeers float better than people.

(歌聲) 馴鹿比人類還能夠飄浮。

But they're huge, how could that be true? Oh well it's physics, you follow?

但它們很大隻耶，怎麼可能浮得起來？嗯，這就是物理，懂嗎？

Their hairs, they're hollow, They insulate much better than you… it's true.

牠們的毛髮，是中空的，牠們比你還能夠保暖...這是真的

A reindeer's coat contains two kinds of hairs:

馴鹿的外皮有兩種毛髮：

A layer of short, dense hair covered with a mesh of longer, hollow hairs.

一層柔軟，濃密的毛，上面再覆蓋一層網狀中空的長毛。

This traps a layer of air in between, which insulates them from the cold, just like those puffy jackets that we wear.

這能夠讓空氣存於毛內這樣可以隔離冷空氣，就像你穿上厚厚的夾克一樣。

This insulation works so well, not only can snow land on reindeer's backs and not melt, with a little jog they can overheat, even in temperatures down to -40 Celsius.

這種隔熱效果非常好，不僅雪落在馴鹿背上不會融化，即使在低至攝氏-40度的溫度下，稍微慢跑它們也會過熱。

Reindeer have 25% more blood vessels packed in their nasal cavities than we do, so they get rid of excess heat through their noses.

馴鹿鼻腔內的血管比我們多 25%，因此它們會透過鼻子排出多餘的熱量。

This makes their noses glow on a thermal camera, and sometimes they even look red to the naked eye.

這使得它們的鼻子在熱像儀上發光，有時甚至肉眼看起來呈現紅色。

But even with his team of flying reindeer, how does Santa get around the world in a single night?

但即使有他的飛行馴鹿隊，聖誕老人如何在一夜之內環遊世界？

There's only so many hours in a day. Well, luckily, he's got more than 24 of them.

一天只有那麼幾個小時。 幸運的是，他有超過 24 個。

If Santa starts delivering presents at, say, 10 p.m. at the international date line and travels west with the rotating Earth, he can circle the globe without losing any time.

如果聖誕老人在晚上 10 點在國際日期變更線開始送禮物，並隨著地球的旋轉向西行駛，他就可以不浪費任何時間繞地球一圈。

Then he can reverse course until kids wake up at 6 AM, giving him 32 hours total to deliver presents.

然後他可以改變方向，直到孩子們早上 6 點醒來，這樣他就有 32 個小時的時間來送禮物。

Let's assume Santa delivers gifts to all 2.2 billion children on Earth, because hey, it's Christmas after all.

讓我們假設聖誕老人向地球上所有 22 億兒童送禮物，因為嘿，畢竟是聖誕節。

At 2.3 children per household, that's 944 million stops.

一個家庭平均有2.3位小孩，所以有9億4千4百萬戶要發。

How far does he have to travel?

這樣他要走多少路呢？

There's about 24.6 million square miles of habitable land on Earth, so if we average out the space between every chimney, that gives us about .026 square miles per household.

地球上大約有 2460 萬平方英里的宜居土地，因此，如果我們平均每個煙囪之間的空間，則每個家庭的面積約為 0.026 平方英里。

If every house occupies an evenly spaced square 0.16 miles apart, Santa's sleigh has to cover more than 150,000,000 miles in 32 hours, which means an average speed of more than 1,300 miles per second.

如果每棟房子都佔據一個均勻分佈的正方形，相距 0.16 英里，那麼聖誕老人的雪橇必須在 32 小時內行駛超過 150,000,000 英里，這意味著平均速度超過每秒 1,300 英里。

That's about 130 times faster than NASA's New Horizons probe, which is the fastest of all fast human things.

這比美國太空總署新視野號探測器快約 130 倍，新視野號探測器是人類所有速度最快的探測器。

Ignoring the fact that at those speeds, Santa's sleigh would burst into flames from air resistance, that gives St. Nick less than 1/10,000th of a second between each delivery.

現在忽略這樣的事實：在這樣的速度下，聖誕老人的雪橇會因空氣阻力而起火，這使得聖尼克每次運送的時間間隔不到 1/10,000 秒。假設聖誕老人要發禮物給地球上22億的小孩，因為

Even if he stopped and got going again instantly at each house, he'd experience acceleration 1.8 billion times Earth's gravity.

即使他在每個房子停下來立即重新開始，他也會經歷 18 億倍地球重力的加速。

If we assume the jolly old fella weighs around 330 pounds, that's a thrust equivalent to about a million and a half Space Shuttle engines.

如果我們假設這個快樂的老傢伙重約 330 磅，那麼推力相當於大約一百萬個半太空梭引擎。

In other words, he'd be a bowl full of jelly. Literally.

換句話說，在這種狀況下，他可能會變成一碗果醬。不誇張地。

This doesn't take into account his payload of gifts, either.

這也還沒將它雪橇上禮物的重量考慮進去。

At two pounds of presents per child, that comes to four and a half billion pounds of Christmas cargo.

假設一位小孩的禮物 2 磅重，這會讓這輛聖誕貨運雪橇重達 45 億磅。

The world's largest cargo plane, the Antonov-225, can carry about 550,000 pounds, meaning we'd need a fleet of almost 8,000 to deliver Christmas.

目前世界上最大的 Antonov-225 運輸機可以裝 5550,000 磅的貨物，也就是說我們會需要至少八千架來送聖誕禮物。

Not only is that pretty bad for the environment, I'm pretty sure you'd hear them flying over your street on Christmas Eve.

這不只對環境很糟，我很確定聖誕夜時你會聽到這些飛機飛過天空。

Clearly, Santa uses other methods.

很明顯聖誕老公公用了其他方法。

I suppose he could generate stocking-to-stocking wormholes, or have spacetime warp drive on board his sleigh, but I've got a different theory.

我想他可以做以長襪為出入口的蟲洞，或是在雪橇上裝設時空曲速引擎，可是我有別的理論。

There's a prediction in quantum mechanics that says every possible observation for the universe is real, that every timeline that can happen, does happen.

在量子力學中有個理論說對宇宙的每個觀察都是真的，所有可能發生的時間線都會發生。

The universe that we live in is just one of of infinite, parallel possibilities.

我們居住的宇宙只是無窮盡的平行宇宙中之一。

Schrodinger's cat, for instance, isn't alive or dead inside the box, it's both.

比方說，薛丁格的貓並不是活著或是死在箱子裡，而是兩者皆是。

This universe contains just one of many possible outcomes.

這個宇宙只是包含了很多可能發生的結果之一，

What if on Christmas eve, Santa creates a universe for all of us, there is one of him for every home, and his real magic is that every Christmas morning, he ties all of our timelines back together, when we open the box to see what's inside.

如果聖誕夜，聖誕老公公為了我們所有人創造一個宇宙，每個人家裡都有一個他，而他真正的魔法是每次聖誕節早上，我們打開禮物看看裡面有什麼時，他把我們的時間線重新組在一起。

Ever wonder why eggnog is the only nog?

有沒有想過為什麼蛋酒是唯一的酒？

The nog part of its name probably refers to a small mug called a noggin used centuries ago in England to serve alcoholic beverages.

它的名字中的“nog”部分可能指的是一種叫做“noggin”的小杯子，幾個世紀前在英國用來盛裝酒精飲料。

Why don't you use your noggin, and subscribe to It's Okay To Be Smart? Happy holidays, and stay curious.

為什麼不使用你的頭腦，訂閱《聰明一點也沒關係》呢？ 節日快樂，保持好奇。