跟讀練習: How to Move the Sun: Stellar Engines - 通過影片學習英語口語

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Nothing in the universe is static.

In the Milky Way, billions of stars orbit the galactic center.

Some, like our Sun, are pretty consistent, keeping a distance of around 30,000 light years from the galactic center,

completing an orbit every 230 million years.

This dance is not an orderly ballet, more like a skating rink filled with drunk toddlers.

This chaos makes the galaxy dangerous.

Our solar neighborhood is constantly changing, with stars moving hundreds of kilometers every second.

Only the vast distances between objects protect us from the dangers out there.

But we might get unlucky in the future.

At some point we can encounter a star going supernova, or a massive object passing by and showering Earth with asteroids.

If something like this were to happen, we would likely know thousands, if not millions of years in advance.

But we still couldn't do much about it.

Unless we move our whole solar system out of the way.

To move the solar system, we need a stellar engine, a megastructure used to steer a star through the galaxy.

It's the kind of thing

that might be built by an advanced civilization with Dyson Sphere

level technology that's thinking about their future millions of years ahead of time.

But how do we possibly move the hundreds of thousands of objects in the solar system?

The good news is we can ignore all of that.

We only need to move the sun, or the other stuff is glued to it by gravity and will follow it wherever it decides to go.

There are lots of ideas about what a stellar engine might look like and how it would work.

We've picked two grounded in our current understanding of physics that could be built in theory.

The simplest kind of stellar engine is the Shkadov thruster, a giant mirror.

It works on the same principle as a rocket.

Like rocket fuel, the photons released as solar radiation carry momentum.

Not a lot, but a bit.

For example, if an astronaut turned on a flashlight in space, it would push them backwards very, very slowly.

A stellar engine will work a little better than a flashlight because the The sun produces a lot of photons.

The basic idea of the Shkadov thruster is to reflect up to half of the solar radiation to create thrust

and slowly push the sun where we want it to go.

In order for the Shkadov thruster to work, it must be kept in the same place, not orbiting the sun.

Although the sun's gravity will try to pull it in, it would be supported by radiation pressure which props the mirror up.

This means the mirror would have to be very light, made of micron-thin reflecting foil from materials like aluminium alloys.

The mirror's shape is important too.

Enveloping the sun in a giant spherical shell wouldn't work because that would refocus light back to the sun, heating it up and creating all sorts of unpleasant problems.

Instead, we use a parabola, which sends most of the photons around the sun and in the same direction, which maximizes thrust.

To prevent accidentally burning or freezing Earth with too much or too little sunlight, the only safe place to build a Skadov thruster is over the Sun's poles.

This means we can only move the Sun vertically in the plane of the solar system

and one direction in the Milky Way, which limits our travel options a bit.

But that is basically it.

For a civilization capable of building a Dyson Sphere, this is a relatively simple endeavor.

Not complicated, just very hard to build.

At full throttle, the solar system could probably be moved by about 100 light years over 230 million years.

Over a few billion years, it gives us near complete control over the sun's orbit in the galaxy.

But in the short term, this might not be fast enough to dodge a deadly supernova.

That's why we thought we could do better.

So we asked our astrophysicist friend if he could design a faster stellar engine for this video.

He did and wrote a paper about it that's been published in a peer-reviewed journal.

You can find it in our sources document.

We're going to call our new stellar engine the Kaplan thruster.

It works a lot like a traditional rocket.

Shoot exhaust one way to push yourself the other.

It's a large space station platform powered by a Dyson sphere that gathers matter from the sun to power nuclear fusion.

It shoots out a very fast jet of particles at nearly 1% the speed of light out of the solar system.

A second jet pushes the sun along like a tugboat.

The Kaplan thruster requires a lot of fuel, millions of tons per second.

To gather this fuel, our thruster uses very large electromagnetic fields to funnel hydrogen

and helium from the solar wind into the engine.

The solar wind alone doesn't provide enough fuel though.

And that's where the Dyson Sphere comes in.

Using its power, sunlight can be refocused to the surface of the sun.

This heats small regions to extreme temperatures, lifting billions of tons of mass off the sun.

This mass can be collected and separated into hydrogen and helium.

The helium is burned explosively in thermonuclear fusion reactors.

A jet of radioactive oxygen at a temperature of nearly a billion degrees is expelled

and becomes our primary source of propulsion from our stellar engine.

To prevent the engine from just crashing into the sun, it needs to balance itself itself.

To do this, we accelerate the collected hydrogen with electromagnetic fields using particle accelerators and shoot a jet back at the Sun.

This balances the thruster and transfers the thrust of our engine back to the Sun.

In as little as a million years, this engine can move the Sun by 50 light-years, more than enough to dodge a supernova.

At full throttle, the solar system can be completely redirected in its galactic orbit in 10 million years.

But wait, won't we use up the Sun this way?

Fortunately, the Sun is so massive that even billions of tons of material will barely scratch the surface.

In fact, this megastructure will actually extend our Sun's life since lower-mass stars burn slower,

keeping the solar system inhabitable for many more billions of years.

With a Kaplan thruster, we could turn the entire solar system into our spaceship.

For example, by orbiting backwards in the galaxy and colonizing hundreds or thousands of stars as we pass by them.

It may even be possible to escape the galaxy entirely and expand beyond the Milky Way.

Stellar engines are the kind of machines built by civilizations thinking not in terms of years or decades, but eons.

Since we know that our Sun will die one day, a stellar engine could allow the far future descendants of humans

to travel to other stars without ever having to venture into the terrifying dark abyss of interstellar space.

Until we build a stellar engine, we're adrift and subject to the whims of the galactic sea.

We may not like where it leads us.

Maybe our descendants will set sail and become an interstellar species for millions of years to come.

This was our last video for the year 12,019 of the human era and what a year it was.

So much stuff happened everywhere to so many different people.

Calendars and holidays are just imaginary, but they help us to cut our lives into pieces pieces that our brains can handle.

We're leaving 12019 behind with a weird mixture of disillusion and hope.

The world is screwed up, but we can fix it.

In a few days, this year will be over, and we'll get to try again.

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音標練習掌握每個音

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詞彙遊戲邊玩邊學

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本課的詞彙與口語要點

這段影片共有 90 個句子、1298 個單詞可供跟讀。講話部分時長為 8:29。說話人語速自然，每分鐘約 153 個詞，接近日常對話。只有 79% 的單詞屬於英語最常用的 3,000 詞，詞彙難度較高。

影片中的重點詞彙

影片中 15 個值得學習的單詞，附發音和釋義：

單詞	發音	釋義
stellar 形容詞	/ˈstɛl.əɹ/	優秀, 出色
orbit 名詞	/ˈɔɹ.bɪt/	軌道 /軌道, 軌跡 /軌跡
galaxy 名詞	/ˈɡæl.ək.si/	恆星系 /恆星系, 群星
sphere 名詞	/sfɪɚ/	球體 /球體
mirror 名詞	/ˈmiɹɚ/	җинзы, 鏡 /鏡
rocket 名詞	/ˈɹɑk.ɪt/	火箭發動機 /火箭發動機, 火箭
ton 名詞	/tʌn/	噸 /噸, 公噸 /公噸
radiation 名詞	/ˌɹeɪ.diˈeɪ.ʃən/	放射, 輻射 /輻射
civilization 名詞	/ˌsɪv.ɪ.laɪˈzeɪ.ʃən/	文明
hydrogen 名詞	/ˈhaɪdɹəd͡ʒ(ə)n/	氫 /氫
thrust 動詞	/θɹʌst/	推力
reflect 動詞	/ɹɪˈflɛkt/	反映, 反射
collect 動詞	/ˈkɑlɪkt/	庋藏, 收藏
fusion 名詞	/ˈfjuː.ʒən/	核聚變 /核聚變
dodge 動詞	/dɑd͡ʒ/	躲避, 躲開 /躲開

影片中的語法

說話人最常用的結構，並附上影片中的原話：

結構	影片中的用法
被動語態 be + 過去分詞 — 強調發生了什麼，而不是誰做的	might be built · is glued · could be built
現在完成時 have/has + 過去分詞 — 過去發生但與現在仍有關聯的事	We've picked · that's been published

需要注意的發音

說話人用了 9 次縮略和弱讀形式，例如 we're, couldn't, doesn't。請按聽到的簡短形式來說。

“th” 音: thrust /θɹʌst/, gather /ˈɡæðɚ/, thin /ˈθɪn/, thruster /ˈθɹʌ.stɚ/, throttle /ˈθɹɔ.tl̩/
“sh” 和 “zh” 音: radiation /ˌɹeɪ.diˈeɪ.ʃən/, civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, fusion /ˈfjuː.ʒən/, shell /ʃɛl/, flashlight /ˈflæʃˌlaɪt/
長單詞——注意重音位置: radiation /ˌɹeɪ.diˈeɪ.ʃən/, civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, electromagnetic /ɪˌlɛk.tɹoʊ.mæɡˈnɛ.tɪk/, complicated /ˈkɑm.plɪˌkeɪ.tɪd/, accidentally /ˌæk.sɪˈdɛnt(ə)li/

如何用這段影片練習

先完整聽一遍影片，不要開口，記下不認識的單詞。
先用 0.75 倍速逐句跟讀，熟練之後再回到正常速度。
錄下自己的聲音並與原聲對比，特別注意 stellar, orbit, galaxy 這類單詞。

什麼是跟讀法？

跟讀法 (Shadowing) 是一種有科學依據的語言學習技巧，最初開發用於專業口譯員的培訓，並由多語言者Alexander Arguelles博士普及。這個方法簡單而強大：您在聽英語母語原聲的同時立即大聲重複——就像是一個延遲1-2秒緊跟說話者的影子。與被動聽力或語法練習不同，跟讀法強迫您的大腦和口腔肌肉同時處理並模模擬實的講話模式。研究表明它能顯著提高發音準確性，語調，節奏，連讀，聽力理解和口語流利度——使其成為雅思口語備考和真實英語交流最有效的方法之一。

影子跟讀法: 閱讀完整分步指南 →

跟讀練習: How to Move the Sun: Stellar Engines - 通過影片學習英語口語

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