When I first saw Star Wars as a four-year-old, it pretty much framed my life and sent me off in my spaceship obsessed course in life.

我四歲時第一次看星際大戰，它幾乎形塑了我的人生框架，使我開始沉迷於宇宙飛船的世界。

Now, Star Wars movies are actually pretty light in terms of physics and science.

星際大戰電影的物理和科學含量並不高。

They're often misclassified as science fiction, when I prefer to call them high-tech fantasy.

它常被錯誤歸納為科幻影片，但我更喜歡稱其為「高科技奇幻影片」。

But there's one very important question for which we can invoke real-life physics.

但還有一個很重要的問題可以用現實生活中的物理學解答。

Just what kind of power does it take to destroy a planet?

到底摧毀一顆星球需要多大的能量？

I mean, three of the seven movies involve devices that are able to destroy planets,

畢竟，七部電影中，有三部出現了可以摧毀星球的設備，

and I should mention that there's a couple of minor spoilers here.

我得提醒大家，以下內容有點小劇透。

And, as it turns out, it's pretty easy to figure out how much energy you would actually take to destroy a planet.

事實證明，我們可以輕易算出摧毀一顆星球所需的能量。

Indeed, in 2001, a paper addressed this issue by calculating the gravitational binding energy of these spherical planet.

實際上，在2001年，一篇論文透過計算球形行星的重力結合能解決了這個問題。

You know, physicists love approximating things to spheres, by the way,

順帶一提，物理學家熱愛用球體進行比擬，

at least with planets that's closer to reality.

至少對於那些較靠近地球的行星是如此。

And with the gravitational binding energy, it's a pretty simple concept for any Kerbal Space Program player.

有了重力結合能的概念，《坎巴拉太空計劃》的玩家都能輕易理解這個概念。

We know that the escape velocity is the critical speed above which an object will escape to infinity and never fall back.

我們知道宇宙速度是指物體脫離地球引力影響所需的最低速度。

Now, imagine that you grab a rock from the surface of the planet and shoot off at escape velocity.

想像一下，你拿起行星表面的一顆石頭，並用宇宙速度拋向外太空。

It's an easy equation to figure out how much energy is required.

我們可以用簡單的方程式算出所需能量。

And repeat that, bit by bit, rock by rock, as you go on, you're actually gonna need slightly less energy

重複這個動作，慢慢地、一顆接著一顆，你需要的能量會隨之變得越來越少，

because as you throw bits into space, there's less mass of the planet left behind to hold them down.

因為隨著你把碎片拋向宇宙，星球的質量也會減少。

But then wait, if you add them all up, using calculus, you get a very simple equation.

但如果你用微積分加總，你會得到一個很簡單的方程式。

The energy is 3/5 times the gravitational constant, times the mass of the planet squared, and divided by the radius of the planet.

所需的能量是 0.6乘以萬有引力常數乘以行球質量平方再除以星球的半徑。

Now, for earth, that number is about 2.25 times 10 to the 32 joules, or in -illion speak, 225 million trillion trillion joules.

以地球來說，這個數字就是2.25乘以10的32次方焦耳，用百萬單位講就是225百萬兆兆焦耳。

However, in the same paper, they went on to calculate that for larger planets like Jupiter.

然而，在同一篇論文中，他們把算式套用在更大的星球上，像是木星。

The energy would be even higher, something like 2 times ten to the 36 Joules.

其能量會高很多，大概是2乘以10的36次方焦耳。

That said, 2 trillion trillion trillion Joules.

也就是2兆兆兆焦耳。

The authors hypothesize that the Death Star may, in fact, be able to destroy this by shutting down some of its non-critical system like life support.

作者假設死星可以藉由關閉一些不重要的系統，如維生系統，來摧毀整個體系。

And they wouldn't put that past the Empire, given there are spotty record on providing basic workplace safety features like handrails.

鑒於銀河帝國工作場所安全的不良紀錄，如沒有扶手，他們不會放過銀河帝國。

Now, this paper is actually underestimating the power of this technological terror, and by extension, the power of the Force.

這篇論文實在是低估了這種科技恐怖的力量，廣義而言，也低估了「原力」的威力。

In Star Wars, we see the destruction of Alderaan, in but a few second, the planet explodes, sending fragments away.

在《星際大戰》中，我們看到奧德蘭的毀滅，幾秒之間，整個星球爆炸，碎片四散。

But assuming that Alderaan is similar to the earth, that exploding ball of plasma is exploding at many times the escape velocity.

但假設奧德蘭跟地球相似，這顆電漿球的爆炸速度是脫離速度的好幾倍。

Look at this demo in Universe Sandbox to show just how slow escape velocity is when you're comparing it to the size of the earth.

這個宇宙沙盤的模擬演示，顯示脫離速度相對於地球的大小而言有多緩慢。

It's not particularly dramatic, unless, of course, you're on the surface of that planet.

這並沒有很戲劇化，除非你站在星球的地表上。

This is, of course, done because Star Wars is a movie, and the audience expects special effects to wow them rather than bore them.

這麼做當然是因為《星際大戰》是一部電影，觀眾想看震撼的特效，而不是無聊的畫面。

If we re-examine the sequence in slow mode, we can see that, within a second, the ball of pulverized planet is about two to three times the size of the original planet.

如果我們以慢動作重新檢視爆炸過程，我們會發現，短短幾秒內，這個粉碎的星球脹成原來的兩、三倍大。

So, the substantial part is moving at over 10,000 kilometers per second.

所以，大部分是以每秒一萬公里以上的速度移動。

We're dealing with velocities many times higher than the escape velocity,

我們正在討論的速率遠遠超過了脫離速度，

and the gravitational binding energy is really a small correction compared to the kinetic energy required to accelerate a planet's worth of mass up to these speeds.

而重力結合能與把一個星球的質量加速到這種程度所需的動能相比，只不過是變數的微調。

To be fair, this is an explosion, and it's more like a range of velocities.

公平而論，這是爆炸事件，所以會有速度範圍。

But even if we take, say, a baseline of 1000 kilometers per second,

不過即使我們採用最低數值，即每秒1000公里，

the energy required to obliterate Alderaan in this manner that will satisfy movie goers, is about 3 times 10 to the 36 joules,

摧毀奧德蘭且能滿足觀眾的能量，大約是3乘以10的36次方焦耳，

are, once again, 3 trillion trillion trillion joules.

或3兆兆兆焦耳。

Now, in The Force Awakens, we have a new generation of planet busting super weapon that can project its beam of destruction over interstellar distances and destroy entire solar systems.

在《原力覺醒》中，出現了新一代摧毀行星的超級武器，它射出的光束能穿越星際，摧毀整個太陽系。

But, moreover, it's powered by a star, which gives me another opportunity to invoke real physics.

更重要的是，它由恆星的能量驅動，這裡實際物理學又派上用場了。

Our Sun emits roughly 3.85 times 10 to 26 watts of power, or again, in -illion speak, 385 trillion trillion joules per second,

我們的太陽大約會釋放3.85乘以10的26次方瓦特的功率，用百萬計算就是每秒385兆兆焦耳，

which means that for our law and estimate, it would take about a week of the sun's energy output to obliterate Alderaan, or 250 years, if you look at my higher estimates.

也就是說，按照我們的定律和估算，摧毀奧德蘭需要約一周的太陽能量，若按照我較高的預估，則需要250年。

Now, in the 10-billion-year life span of a star, that isn't so bad.

這對恆星100億年的生命週期來說不算什麼。

But I do have some straight out problems with this.

但我確實對此有些疑問。

Maybe I missed it, but it seems to me that they weren't planning on moving Starkiller Base around.

也許是我漏看了，但他們似乎不打算移動弒星者基地。

After all, the energy required to move a planet into hyperspace is probably similar to the energy required to destroy a planet by moving its different pieces at several kilometer per second in different directions.

畢竟，把行星移入多維空間所需的能量可能跟為了摧毀行星而以每秒幾公里的速度讓碎片四處飛散差不多。

But if you had to consume the entire star to do that, then you would need another star, and if it can't move,

但如果你得毀滅一整顆恆星才能達到目標，那你就需要另一顆恆星，如果它無法移動，

well, you gonna get another star, it seems like bad planning.

你就得再找一顆行星，這個計畫似乎很糟。

I mean, you don't even need mathematics to figure this out.

我是說，根本不用計算就會發現它行不通。

Okay, look, scriptwriters, hello! Look, there's a way to fix this.

各位編劇，看過來！有一個很簡單的解決方法。

There are stars that have luminosities that are something like a million times higher than the sun.

有些恆星會自行發光，亮度是太陽的一百萬倍。

They're short-lived, but they can generate the energy required for epic planet busting for millions of years,

它們壽命很短，但能量足以引發持續數百萬年的星球大爆炸，

long enough for any movie franchise.

絕對足夠拍攝各種電影系列。

Starkiller Base could soak up all the power it wanted to from the outer layers of these stars,

弒星者基地能從恆星外層吸收所有能量，

and it could then even make the star turn from blue through red to black, as the energy was siphoned off,

隨著能量被吸收，它甚至能讓恆星從藍色變成紅色，再變成黑色，

giving those X-wing pilots a way to gauge how long they had left in a visually arresting style.

用極具視覺震撼力的方式讓X翼戰機飛行員判斷其飛行時間。

And then, of course, after the siphoning stopped, the star would return to normal energy output and be ready for firing again in a few days' time.

當然，虹吸作用停止後，恆星的能量釋放會恢復正常，幾天後就能再重新發射。

Of course, the scriptwriters never asked me. Regardless, if you really wanna go into planetary destruction to strike fear into the hearts of your enemies,

當然，編劇沒來問過我。無論如何，若你想用摧毀行星恐嚇敵人，

the Empire and the First Order are going way overboard, making millions of voices cry out in terror.

銀河帝國和第一軍團的方法顯然太過激進，使數百萬人哀嚎遍野，

It just requires obliterating the top, a 0.1% of the planet near the surface.

其實只需要破壞地表最上方0.1%的面積。

The other 99.9% of a planet is generally things like magma that isn't particularly hospitable to life.

剩下的99.9%通常是岩漿之類的東西，本來就不適合生物生存。

I'm Scott Manley. Fly safe.

我是Scott Manley，飛行平安。