There are roughly 102,465 commercial flights each day which, over a year, equates to about four billion air passengers per year.
世界上每天都有大概102,465個班次的商業航班，換算成一年，差不多就是40億人次。
That's over half of the world's population who've sat on a flight, often for hours on end, and had time to think about planes and ask questions about them.
這所有坐過飛機的人已經超過地球人口的一半了，而且他們通常一坐就是幾小時，有充足的時間來思考飛機的方方面面並對它們提出問題。
If you've ever stared out the window as your plane takes off, you will have seen a tiny hole in your window.
如果你曾經在飛機起飛的時候盯著窗外看，你會發現窗子上是有小洞的。
At first, it may seem like a weird addition, especially in something that's carrying a lot of people at a great height, but they're there for a very important reason: to stop the cabin from depressuring.
乍看之下，這個細節很詭異，尤其是它還出現在一個載著這麼多人、飛得這麼高的東西上，但其實它是有重要作用的：防止機艙減壓。
As the plane gains altitude, the air pressure outside drops compared to the regulated air pressure inside the cabin.
隨著飛機的飛行高度增加，飛機外面的氣壓會低於飛機內收到調控的氣壓。
The difference between the two puts physical stress on the windows - made up of three panes of glass.
兩側的氣壓差會對窗戶造成物理壓力。(飛機的窗子是由3層玻璃組成的)
There's a small air gap in between the middle and outer panes and the hole is actually in the middle pane.
在中層玻璃和外層玻璃之間有一個空氣層，而這些小洞實際上是位於中層玻璃上的。
If you ever wondered what it's called - it's a "breather" or "bleed hole" - and it balances the pressure between the cabin and the air gap.
你可能好奇過它們叫什麼。它們被稱為「呼吸孔」或者「出血孔」——它們能平衡機艙與空氣層之間的壓力。
The outer pane takes the pressure, whereas the middle pane acts as a fail-safe just in case that trusty outer pane fails. Perish the thought.
承受壓力的是外層玻璃，而中層玻璃則是一層保險，以防那層可靠的外層玻璃突然時效了。不過你還是打消這個想法吧。
So we now know the crucial function of those tiny holes in aeroplane windows which previously might have made you panic mildly.
好，現在我們已經知道飛機窗戶上那些小洞有多麼重要的作用了，而這玩意以前可能會給你帶來點小恐慌。