For sure, tsunamis hundreds of meters high would destroy coastal cities,

爆発させたらどうなるだろう?

earthquakes would level countries,

きっと数百mの津波が海岸の都市を襲い

new volcanoes would bring us nuclear winter.

地震が国々をなぎ払い

Maybe even Earth could be ripped apart?

新しい火山が核の冬をもたらすだろう

Or thrown out of orbit?

もしかすると地球の軌道すら 変わるかもしれない

Well, almost.

きわどい話だ

Currently, Earth's deepest known point is inside the Mariana Trench.

地球で一番深い場所は マリアナ海溝にある

The Mariana Trench is a very deep valley

マリアナ海溝は深い谷で

right at the edge of two tectonic plates

2つのプレートの 出会うところで

that looks like an upside-down mountain.

逆立ちした山の ような形をしている

It reaches a depth of about 11 kilometers,

深さは約11kmで

almost three times deeper than the dark grave of the Titanic.

タイタニック号の沈没地点の ほぼ3倍も深い

It's one of the last places on Earth for humans to explore.

人類が探査すべき最後の 場所となっている

Pitch black and under a thousand atmospheres of pressure,

漆黒の闇と千気圧の水圧のため

it's a relatively pristine environment thanks to the absence of humans.

人跡未踏の環境であり

A great place for our nuclear test.

無人なのだから

We'll use the most powerful nuclear bomb humans have ever exploded,

核実験にはいい場所だ

the RDS-220 hydrogen bomb or Tsar Bomba.

最大の核兵器とは

Its explosion was so massive that its shockwave traveled around the Earth three times,

RDS220、またの名を ツァーリ・ボンバという

and its mushroom cloud stretched 56 kilometers into the sky.

その爆発は巨大で 衝撃波は地球を3周し

Its shockwave was strong enough to destroy everything in a thousand square kilometers,

キノコ雲は56km上空に達した

its fireball hot enough to burn the rubble.

衝撃波は1000平方kmの 範囲を破壊し尽くし

Bombs like this release such an enormous amount of energy at once, that they could boil away an entire lake.

火球の熱は瓦礫を焼き尽くした

And if we set off a nuclear bomb in the Mariana Trench, that's exactly what happens.

一瞬のうちに放出された 膨大な熱は

Let's pull the trigger.

湖を沸騰させるほどだった

In the first few microseconds, the nuclear fuel undergoes its chain reaction

そこでマリアナ海溝に 核兵器を設置したら

and explodes with the power of 50 megatons of TNT.

実際はどうなるのだろう

A blinding flash of light illuminates the darkness of the trench for the first time in history.

では起爆させてみよう

The heat of the explosion produces a cavity, a flaming bubble of water vapor,

最初の数マイクロ秒で 核燃料に連鎖反応が進行し

radioactive nuclei, and the remains of very unlucky fish.

50メガトンのTNT火薬に 匹敵する力で爆発する

The bubble grows quickly as it vaporizes the water around it.

史上初めて海溝の闇は 閃光によって照らされる

The pressure of the bubble is immense, plowing outwards as if there's nothing in the way.

爆発の熱が形成する 灼熱の気泡には水蒸気と

Sending off a shockwave that will be felt by seismic stations and whales around the world.

放射性核種と 不運な魚が含まれる

And then, almost as fast as it emerges, it stops.

気泡は周囲の水を 気化させながら増大する

On the surface of the Earth, this fireball bubble would grow to ten kilometers the second after it's detonated,

気泡の圧力は巨大で 行く手にあるすべてを薙ぎ払う

as the atmosphere barely puts up a fight to hold it back.

世界中の地震観測点とクジラが 感知するほどの衝撃波を送り出す

But the pressure at the bottom of the Mariana Trench is enormous.

しかし発生したのと 同じくらい速やかにそれは停止する

With 11 kilometres of water overhead,

地上ではこの火球は爆発後 1秒で10kmに達し

being in the Mariana Trench is like being crushed by a hydraulic press from every direction.

やっと大気によって 押し戻された

Here, a second after the detonation, our bubble is about a kilometer across, when oddly enough, it starts to shrink.

しかしマリアナ海溝の 底では水圧は莫大だ

The bubble overextends itself, losing pressure as it expands, until the water turns it back, recompressing it.

頭上に11kmの水が あるのだから

The tug of war between the fiery death bubble and water goes back and forth a few times,

マリアナ海溝ではたえず周囲から の水圧で押しつぶされることになり

the bubble shrinking and growing, until eventually the bubble loses for good.

ここでは1秒後には気泡は 直径1kmに達したのちに

The pressure around it is too great, and turbulent water begins to chop it up.

縮み始める

It becomes something like the underwater equivalent of a mushroom cloud

気泡は拡大し過ぎると 圧力が低下し

as it disintegrates into many smaller, hot and radioactive bubbles drifting upwards.

水圧に押し戻されて 再度圧縮される

And as our mighty destructive blast rises to the surface, it does basically nothing.

火の玉と水の間の戦いは 何度か押し引きし

Just a small wave, and a bubbling plume of radioactive warm water in the Pacific.

最終的には縮小してゆく

No tsunami will wash away Japan or California,

周囲の圧力があまりに強いのだ

although boats and whales in the area might have a bad time.

それは水面下でキノコ雲に 相当するものになる

The radioactive fallout will be diluted into the Pacific after a few days,

細かく崩壊し、熱くて放射能を 帯びた泡となり上昇する

although a fair amount of radioactive water and salt makes it to the atmosphere

破壊的な爆発は水面に 達する頃には

where it collects and then rains down again.

基本的には 何でもなくなっている

Even if the wind blows the fallout directly towards the Philippines,

小さな波と、放射能を帯びた 温かい海水の泡だ

the worst of it probably happens over the oceans.

日本にもカリフォルニアにも 津波は来ない

But clearly, the real danger comes from our explosion-triggering earthquakes and volcanoes, right?

でもあたりの船や クジラには影響がある

Even if we detonated the bomb right in the trench at the exact point where tectonic plates touch, probably not.

放射性降下物は数日で 太平洋に希釈されるが

The explosion would vaporize a part of the seafloor, and turn a lot of sand into glass,

それなりの量の放射能を帯びた 水と塩は大気循環に乗り

but most of the energy goes into the water, not seismic waves.

濃縮され雨となって 降ってくるだろう

Earthquakes are already quite common at tectonic plate boundaries.

降下物は直接フィリピンに 風で降ってくるが

And earthquakes with as much seismic energy as our bomb

最悪なのは洋上だろう

happen a few times a year without triggering any sort of apocalypse.

でも一番危険なのは地震や 火山噴火なのでは?

But maybe it will affect the Earth's orbit.

プレートが接する直上で 起爆したとしても

Since no mass is taken away or added to the Earth, our orbit is completely unaffected.

たぶん大丈夫

Also, there have been well over a thousand nuclear tests in the last 70 years

爆発は海底の一部を 蒸発させて

and that didn't change our orbit, so why would this time be different?

砂をガラスに変えるだろうが

The strongest forces humanity can unleash are laughable compared to the forces of nature.

エネルギーの大部分は 地震波ではなく水に移行する

The planet is too big. It doesn't care.

地震はプレート境界では ありふれている

So, what happens to us if we detonate a nuclear weapon really deep in the ocean?

核兵器なみの エネルギーの地震も

Pretty much nothing.

特に引き金がなくても 年に数回は起こっている

Did you know that every bird in our videos has an owner?

でも地球の軌道は大丈夫か?

More than 1,000 people have got their own bird.

質量が失われたわけでも 付け加わったわけでもないので

It helps us explain things, clowns around in the background,

軌道は大丈夫

or dies a horrible and avoidable death.

ここ70年の間に千回以上の 核実験があったが

If you want your own bird too and you want it to appear in one of our videos,

軌道に影響はなかったんだから

you can get it at patreon.com/kurzgesagt.

人類が解き放つ最大の力といえども 自然界の力に比べれば話にならない

Patreon is one of the main ways we sustain ourselves.

惑星は大きいのだから 気にする程ではない

So on top of getting a super nice avatar, you also help us make more and better videos.

では深海の底で核兵器を起爆したら ホントのところ何が起こるのか?

[Quacking]

ほとんど何も起こらない

[Outro music]

我々の動画に出てくる鳥には すべてオーナーがいるのを知ってますか?