The sun releases more energy

太陽が150万分の１秒に 発するエネルギーは―

in just 1.5 millionth of a second

地球上の１年間の消費量より多い

than we humans on planet Earth consume in a year.

すごいパワーよね

That's a lot of power.

[番組ホスト　マレン･ハンスバーガー]

Which is why solar will likely play a huge role

太陽エネルギーは 今後―

in our quest for a cleaner, more secure energy future.

よりクリーンで安全な エネルギー源となるはず

The sun generates all of this energy

太陽は核融合によってエネルギーを生み出す

through a process called fusion.

では核融合とは どんなもので―

But what exactly is fusion,

エネルギーはどのように生み出されるのか？

and how does the sun generate so much energy?

[オーストラリア　アウトバック]

The sun is a massive nuclear powerhouse

太陽は巨大な原子力発電所

that can raise temperatures in the Australian Outback

それにより アウトバックの気温は なんとセ氏50.7度まで上がる

to an incredible 50.7 degrees Celsius.

ワールドソーラーチャレンジを走る レースカーにとって完璧な燃料ね

That intense energy is perfect for fueling race cars

ここはオーストラリアのアウトバック

competing in the World Solar Challenge.

ご覧のとおり 非常に過酷な環境だ

DEREK: I am in the middle of the Australian Outback.

ここにいると太陽の力を感じる

As you can see,

[デレク･ミューラー]

this is a very inhospitable environment.

あり得ないほど暑い

You know, it's funny being out here,

この暑さこそが―

you feel the power of the sun.

車を高速で走らせるエネルギーになる

It gets so stinking hot.

20ヵ国以上から集結した チャレンジの参加者たちは―

And of course, it is that very energy

オーストラリア大陸を縦断し 約3,000キロを走破

which is propelling these cars down the road

世界最速のソーラーカーを目指して競います

at incredible speeds.

ソーラーカーの動力源があるのは―

And in the World Solar Challenge,

地球から１億5,000万キロかなた

cars from over 20 countries

亜原子粒子が含まれる

have to power across the whole continent,

物質を構成するのは原子よ

going 3,000 kilometers, over 1,800 miles,

原子の中央にある核は 陽子と中性子から成り―

to claim the title

核の周りを雲状の電子が回ってる

of world's fastest solar vehicle.

高エネルギーの環境で―

MAREN: Incredibly, the power source

２つの原子核が合体して 核融合が起こる

that makes all of this possible

次のような場合とは違うわ

is 150 million kilometers away

電子によって結びついたり―

and involves subatomic particles.

水素原子２つと酸素原子１つから 水ができる場合よ

You may know that atoms, which make up all matter,

これは“結合”

have a nucleus at the center

核融合では原子核同士を―

made up of protons and neutrons,

衝突させて１つの原子核を作るの

with electrons zipping around the nucleus in a small cloud.

この時 膨大な量のエネルギーが生じる

Fusion happens when two atomic nuclei

核融合の基礎については理解できたわね

are forced together

次は太陽の核融合を 見てみよう

in extremely high-energy conditions.

まず原子核の合体に―

Now, keep in mind,

大量のエネルギーを必要とする

this is different from what happens

正電荷を持つ陽子は 互いに反発するからよ

when atoms link together using their electrons,

同じ電荷は反発して―

like when two hydrogen atoms and an oxygen atom

反対の電荷は引き合う磁石と同じね

come together to form water.

でも太陽は途方もなく巨大よ

That's called bonding.

直径は約139万2,000キロ

But in fusion,

強力な重力が働いてる

the nuclei of the atoms themselves

つまり 太陽を成す水素原子に 強大な圧力がかかってるの

need to smash together to form a single nucleus,

核融合は 太陽の中心部で起こる

and this process releases massive amounts of energy.

中心部は 高圧力で高密度の状態よ

Okay, so, now that we've got our heads wrapped around

水素原子の正電荷を持つ 陽子同士が―

the very basics of how fusion works,

ここで融合してヘリウムになる

let's take a look at how it happens in the sun.

さらに詳しく説明するなら―

First off, it takes a lot of energy

p-p連鎖という反応の話になる

to force the nuclei to come together

太陽が放出するエネルギーは 一連の熱核反応の結果なの

in the first place,

反応の第１段階

because protons, all with the same positive charge,

２つの水素原子が衝突し―

repel each other.

重水素が１つできる

You know, like magnets.

陽子１つと中性子１つから成る水素原子よ

You may recall that principle

ほとんどの水素原子は中性子を持たない

that like charges repel

次に３つ目の水素原子の陽子が 重水素の核に衝突し―

while opposite charges attract.

三重水素の核であるトリトンができる

However, the sun is so massive,

陽子１つと中性子２つを持つ

roughly 1.392 million kilometers in diameter,

２つの三重水素の核が融合して―

that it has an insane amount of gravity,

ヘリウム４の核ができる

meaning there's an incredible amount of pressure

陽子２つと中性子２つから成る

exerted on all those hydrogen atoms

この核融合で２つの陽子が発生し 反応が繰り返される

that make up the sun.

２つの陽子が衝突し―

Now, solar fusion happens inside the sun's core,

３つ目の陽子が加わる

where the pressure is so intense

２つの三重水素の核が融合して―

and the density is so great

陽子２つが発生する

that those like-charged protons

水素がある限り 反応は繰り返されるの

of those hydrogen nuclei

理解できた？

smash together to form helium.

複雑な過程よ

If we want to break things down

まさに熱核反応の物理学ね

in even greater detail, which we do,

もう一度 確認したい人は―

we'll have to talk about something

3:53からのp-p連鎖に戻ってね

called the proton-proton cycle.

この過程で どれくらいエネルギーが生じるか？

The energy radiated by the sun

科学者たちの計算によると どんな場合であれ―

is really the result of a series

約384ヨタワットのエネルギーを放出してる

of thermonuclear reactions.

私もだけど こんな単位は初耳でしょ？

The first step in the reaction...

科学的記数法で言うと―

two hydrogen nuclei collide

10の26乗の3.84倍のパワーということ

to produce what's called deuterium,

つまり 384に０が24個つくことになる

a hydrogen nucleus

画面が０であふれちゃう

with one proton and one neutron.

ヨタは大きな数字を簡単に表せる―

See, most hydrogen atoms have only one proton

便利な単位ね

and no neutrons.

不安定で長期にわたる放射性廃棄物は 核融合では出ない

Next, a third hydrogen proton

その点が核分裂とは違う

smashes into the deuterium nucleus

核融合で生じるのは―

to make a tritium nucleus, or a triton,

非放射性の副産物である ヘリウム

a nucleus with one proton and two neutrons.

エネルギー源としての実用化が すでに研究されてる

When two of these tritium nuclei fuse together,

でもコメントにもあるように―

they form a helium-4 nucleus

みんな まだ数十年先のことと思ってる

with two protons and two neutrons.

太陽エネルギーは 太陽系に散乱してる

This fusion also releases two protons,

４垓3,000京ジュールの太陽エネルギーが

allowing the cycle to continue.

地球の表面に届いてるの

Two hydrogen protons collide,

１時間または１時間半あたりの量よ

a third hydrogen proton joins the party,

世界全体のエネルギー消費量は―

two of these tritium nuclei fuse together,

年間５億8,000万テラジュール

two protons are released.

仮に２時間分の太陽エネルギーを すべて効率的に利用できるとすれば―

Repeat, and repeat, and repeat

１年以上 世界中に供給できる

until the sun runs out of hydrogen.

当分 実現は無理だと思うけどね

Got it? Great.

でもクリーンで持続可能な エネルギーへの転換に―

It is a complicated process.

太陽エネルギーは役立ってる

After all, it's literally thermonuclear physics.

ここ数年 技術がさらに向上して すばらしい革新が見られる

So, if you want to go and run that animation back,

次回はソーラーパネルを取り上げるわ

go ahead and rewatch

太陽光を馬力に変えて供給できる―

that proton-proton cycle animation.

技術について紹介するわね

Now, you may be asking,

how much energy does this process generate?

Well, scientists have calculated

that at any given moment,

the sun releases

an estimated 384 yotta watts of energy.

Never heard of a yotta watt before?

Because me neither.

But using scientific notation,

that's 3.84 times 10 to the 26th power.

So, 384 with 24 zeros behind it.

We barely have enough screen

to actually show all of those zeros.

Saying that's a "yotta" power

would be a gross understatement

and a groanable pun.

And because nuclear fusion doesn't produce unstable,

long-lived radioactive waste like nuclear fission does,

that's the splitting of an atom,

instead, fusion results in a stable,

non-radioactive by-product of helium.

So, scientists are exploring

how to develop this as a viable energy source.

But as many of our secret viewers have noted,

fusion technology always feels like

it's just a few decades away.

Now, while most of the sun's energy

is scattered across our solar system,

researchers have estimated that 430 quintillion joules

of the sun's energy

hits the surface of the Earth

roughly every hour, or hour-and-a-half.

With current estimates

of total world energy consumption

at 580 million terajoules annually,

that means, theoretically,

if we could effectively harness all of the sun's energy

that hits Earth for just two hours,

we could power our entire planet

for more than a year.

Clearly, this isn't a reality, at least not anytime soon,

but solar energy is helping power a worldwide shift

to cleaner, more sustainable energy.

And there have been some

incredible innovations in recent years

as the technology has become more and more efficient.

So, next up, we take a closer look at solar panels

and break down the technology

that powers our homes and cities,

and can transform sunlight into horsepower.