alive. It looks like we'll only ever have small  crews spend a miserable time hidden underground.  

もし滞在すれば 悲惨な目に遭うかもしれない

Except, we could terraform it into a green  new world. But to solve the planet's problems,  

だが地球化できれば 話は別だ

we first need to make it worse and turn it  into oceans of lava with gigantic lasers.

そのためには まず巨大レーザーで

This isn't a far-fetched science fiction tale.  Terraforming Mars is possible, on the kind of  

溶岩の海を作る必要がある

time scale our ancestors built great monuments  in. If humanity solves some of its pressing  

これは超SFの話ではない

problems and ventures into space to expand into  the solar system, this may not be that far off.

長期的視点にたてば 火星の地球化は可能だ

Ok. So how do we terraform Mars  quickly? Well, It's complicated.

もし人類が喫緊の課題を解決でき 他の惑星にまで進出できれば

Mars is dry and has no soil to grow anything. Its  atmosphere is too thin to breathe or protect from  

実現できそうなものだ

radiation, giving you a high risk of cancer.  So to turn it into a new home for humanity,  

よし、だがどうやって 地球化するのか

we have to give it a proper atmosphere, similar  to Earth's. It should be made of 21% oxygen,  

まあ、話は複雑だ

79% nitrogen and a tiny bit of CO2, at an average  temperature of 14°C and under 1 bar of pressure.

火星は乾いており 土壌も悪い

We have to create oceans and rivers and then the  ground has to be weathered into fertile soil to  

大気は薄く、紫外線も防げず 癌になるリスクも高い

host living things. Then we need to install  a biosphere on the surface and prevent it all  

なのでこの新しい家には 地球と同じような大気が必要だ

from being undone by installing protective  measures that can stand the test of time.

それは21%の酸素と79%の窒素 僅かなCO2ででき

It's difficult. But a big  laser makes it a lot easier.

平均温度は14℃で 大気圧以下である必要がある

Challenge 1: The Atmosphere

海や川を作り、生き物が住める 肥沃な土壌も必要だ

Some 4 billion years ago Mars had a nice  oxygen-rich atmosphere and was home to vast  

そこに生物を導入し 成果を無駄にせぬよう

oceans and rivers. It held onto it for  several hundred million years before it  

時の試練から保護する必要もある

got blown away. Ultraviolet rays broke down  the atmospheric gases and then the oceans,  

まあ難しい だが巨大レーザーがあれば話は簡単だ

until they were swept away by solar wind.  Today Mars is a dry, barren wasteland.

挑戦その1 大気

Luckily a sizable portion of the water is frozen  in deep reservoirs and in the polar ice caps,  

約40億年前、火星はいい感じに 酸素が豊富な大気や

enough to create a very shallow ocean.  And enormous amounts of oxygen are bound  

広大な海や川が存在していた

as minerals in the Martian rocks,  like the oxygen in the iron oxides  

だが紫外線によって大気や海が分解され 太陽風に吹き飛ばされたのだ

that give the planet its rust-red colour,  as well as carbon dioxide in carbonates.

現在の火星は 乾燥した不毛の地である

To free these gases, we need to  reverse the reactions that lock  

幸い、巨大な氷が 極地や地中に存在し

them away by using thermolysis,  which occurs at temperatures as  

浅い海を作るには 十分な量がある

high as on the surface of the Sun. In  short, we want to melt Mars' surface.

また火星の岩石は CO2や大量の酸素を含み

The best way to do that would be to put lasers  in orbit aiming their beams down on Mars.  

これが鉄が錆びた時の赤褐色を 火星に与える原因となっている

The most powerful laser today is the ELI-NP,  

これらのガスを解放するには 太陽のような高温による

able to produce beams of 10 Petawatts  of power, for a trillionth second.

熱分解を利用する必要がある

To melt Mars we need a laser twice as powerful,  that runs continuously. The easiest way is to use  

つまり、火星の表面を 溶かせばいい

a solar-pumped laser that can be powered directly  with sunlight: At its core are metal-infused glass  

軌道上に火星を焼くレーザーを 設置する方法が最良だ

rods that absorb energy and release it as a laser  beam. If we build an array of mirrors in space,  

現在最強の ELI-NP は

about 11 times the size of the United States, we  can focus enough sunlight onto them to melt Mars.

10ペタワットのビームを 1兆分の1秒放てるが

Let's do it!

火星には2倍強力で 連続照射できるものがいる

As the lasers hit the surface, about 750  kg of oxygen and some carbon dioxide emerge  

最も簡単な方法としては 太陽光で直接動くレーザーがいい

from every cubic meter of rock melted. If  we are efficient our lasers only need to  

金属入りのガラス棒でできた 太陽光をレーザーとして放つ装置だ

melt through the top 8 meters of  the surface to get enough oxygen.

アメリカ国土の11倍の鏡を 宇宙に設置できれば

It would look terrifying. The  skies would be shrouded in storms,  

火星を溶かすのには十分である

while the ground would glow red-hot,  criss-crossed by currents of lava.  

よし、やろう

Tireless laser beams sweep over the landscape,  leaving trails too bright to look at. After they  

レーザーが当たると 750kgの酸素と少量のCO2が

pass, the ground cools quickly. A strange  snow falls: the ashes from all the elements  

1m³ごとに解放される

that solidify as they cool down, like silicon and  iron. Mars is still a cold planet at this point.

表面を8mも溶かせば 十分な酸素が得られるだろう

A happy side effect of this inferno is that  all the water in the polar ice caps and even  

見た目は恐ろしい

deep underground rises into the sky as hot  steam, forming clouds that rain down over  

空は嵐に覆われ 地表は流れる溶岩で赤く輝き

the entire planet. They would wash out  the nastier gases from the atmosphere,  

レーザーは地を一掃しながら 直視に耐えぬ光跡を残す

like chlorine, and carry away harmful elements  that accumulated on the surface. In the end, they  

その後は急速に冷えていく

would form shallow oceans, saltier than on Earth.  We might need to do an extra clean-up afterwards.

ケイ素や鉄などの冷えると固まる元素が 奇妙な雪のように降るだろう

It would take about 50 years of continuous  lasering to create our oxygen atmosphere. We  

火星はいまだ冷たい星なのだ

could use this opportunity to dig deeper in some  places to create the basins for salty oceans or  

この地獄絵図の嬉しい副作用は 極地や地下の氷が

rivers and spare some landmark features  like Mons Olympus and Valles Marineris.

熱い蒸気となって空に昇り 雲を形成し降り注ぐことである

We're not done though.

雨は有害物である塩素ガスや 地表に蓄積されていた元素などを洗い流し

The resulting atmosphere is nearly 100%  oxygen and only 0.2 bar. It's hard to  

最終的に地球より塩濃い 浅い海をつくるだろう

breathe and very flammable. To make  it similar to earth and a lot safer,  

追加の掃除は必要だろうが

we need to add a lot of nitrogen, which  Mars is lacking sadly. We have to import it.

大気の形成には 50年間レーザーを照射する必要がある

The ideal source is Titan, a large moon of Saturn,  covered in a thick atmosphere that's almost  

この機会に彫り方を選び 海や川を作っておくのもいいだろう

entirely nitrogen. We just have to move 3000  trillion tons from the outer solar system to Mars.

オリンポス山やマリネリス峡谷などを 保護することもできる

While that's not easy, it is doable. To  process that much of Titan's atmosphere,  

まだ終わりじゃない 酸素100%の大気が0.2気圧分得られただけで

we have to construct giant automated factories,  on its surface powered by our lasers to suck in  

呼吸もできず 燃えやすすぎる

the atmosphere and compress it into a liquid.  This gets pumped into bullet-shaped tanks,  

大気を地球に似せるには窒素が必要だが 残念ながら火星にはなく

which a mass driver shoots all the way to  the red planet, where they explode and mix  

輸入に頼るしか無い

with the oxygen. We've already been able to send  individual missions to Saturn in just a few years.  

土星の衛星タイタンは厚い窒素の 大気を持つ理想的な供給源だ

With enough resources, it should be possible  to complete the task within 2 generations. 

3000兆トンを火星に移せばいい

Of course it would be much more  convenient to have nitrogen left  

難しいがなんとかなるだろう

over from terraforming Venus on the side: we  explained this in detail in another video.

ただし巨大な自動化工場を 建てなければならない

So, about a century after the  start of the terraforming process,  

レーザーを動力源に 大気を吸って液化させ

we have a breathable atmosphere that has  the right gases. If the liberated CO2  

弾丸状のタンクに詰め込んで 火星に打ち込み大気に混ぜるのだ

isn't enough to warm it up to temperatures we  can stand, we just add some super greenhouse  

人類は既に数年で土星まで 機械を送れている

gases. Mars at this point resembles a  black marble from all the cooling lava,  

資源があれば2世代以内に 任務を完了できるはずだ

spotted with growing oceans and red patches  where the old surface remains untouched. It's  

もちろん金星の地球化で余った 窒素を使えるならありがたい

still a wasteland, no better than a desert  on Earth. We need to fill it with life.

金星の地球化は別の動画を見てほしい

Challenge 2: Biosphere

地球化を開始した100年後には 呼吸可能な大気ができているだろう

Installing a biosphere on a new planet is  very difficult. Unexpected interactions  

もしCO2が十分でなければ 温室効果ガスを追加して温められる

between species or sudden diseases can  destabilise it to the point of collapse.

そこは溶岩が冷えて黒い大理石のようになり

We would probably begin by seeding our young  oceans with phytoplankton. Without competition,  

海は成長し 赤く古い地形も残された姿である

it would bloom rapidly, filling up the oceans  to become the bottom of an aquatic food chain.  

まだ地球の砂漠と変わらない荒れ地であり

They can be followed by tiny zooplankton,  

生命で満たす必要がある

then by fish. Maybe even sharks and whales. If  things go well, life in the oceans will thrive.

挑戦その2 生物圏

Life on land is harder. Plants need  nutrient-filled ground to sink their roots  

新規に生物圏を導入するのは難しい

into. But most of the surface is the congealed  remains of lava and ashes. We could wait for  

種族間の思わぬ相互作用や病気もあり 安定には時間がかかる

thousands of years for water and wind to grind it  down into finer sands or try to do it manually.

まず海への植物プランクトン導入がいいだろう

But we want to be quick. And we have a  big laser. Turning the beam on and off  

競争なき海で繁殖し 食物連鎖の基礎となってくれる

in rapid succession would cause the ground to  quickly heat up and contract, which breaks it  

その後に動物プランクトンや魚と続き

into smaller and smaller pieces. Add a bit  of water, and you get a sort of dark mud.

サメやクジラもいれよう

Into this mud, we can mix fungi and  nitrogen-fixing bacteria. They're  

うまくいけば海洋の生物は繁栄するだろうが

able to absorb nitrogen and convert it  into nitrate compounds to feed plants.  

陸はもっと難しい

The first plants we want to bring are  native to volcanic islands on Earth,  

植物は栄養ある土を必要とする

since they are perfectly suited to  the laser-blasted Martian landscape.

しかし殆どの地面は 溶岩と灰が凝固した岩だ

Eventually, the enriched mud becomes the  foundation for grasslands and forests. In  

風雨による風化を何千年と待つこともできるが 人が手を貸すこともできる

Mars' lower gravity, trees can become very tall  very fast. Their roots gather the nutrients  

早い方がいい 幸い巨大レーザーがある

they need and then dig deeper to turn more rocks  into soil, forming a self-sustaining ecosystem.

レーザーを入り切りすれば 地面は膨張収縮を繰り返し

At this point we can slowly introduce more plant  varieties, insects and animals. Not mosquitoes  

どんどん細かな破片に分解され

though. The new biosphere needs to be maintained  to prevent it from falling out of balance. If  

そこに水を加えれば 黒い泥ができる

plants grow too quickly and absorb too much  carbon dioxide, the planet cools down too much.  

これに菌類やバクテリアを 混ぜることができるのだ

If key species die out, we could see populations  collapse faster than they could recover. On Earth,  

これらは窒素を硝酸化合物に換え 植物の成長を助けてくれる

other species would move in to fill the void,  but our Martian biosphere is not as flexible.

初の入植者は 火山島由来の植物がよく

It takes hundreds if not thousands of years  before Mars becomes a stable environment.

レーザーで焼かれた火星にぴったりだろう

But eventually the planet will have the potential  to sustain large human colonies. With air,  

濃厚な泥は後に 草原や森林の基礎となる

water and food available, we  can finally call Mars – black,  

火星の低重力下では 木は早く高く成長するだろう

blue and green – our home. A  giant, volcanic island in space.

根は栄養のために掘り進んで 岩石を土へと変え

Will it last though?

独特の生態系を築いてくれる

Challenge 3: The long-term future

これ以降、植物や昆虫 動物を徐々に導入できる

There is a problem we haven't addressed: Mars'  core does not produce a magnetic field, so it does  

ただし蚊はダメだ

not have enough protection from solar radiation  or cosmic rays. This becomes dangerous for the  

新しい生物圏は安定を維持する必要がある

long term health of Martian populations. So as a  final step, we need an artificial magnetic field.

もし植物が急成長しCO2を奪えば 火星は冷却が進む

It doesn't have to be huge like Earth's. It  

もし重要な種が滅べば 回復できず崩壊するかもしれない

just needs to deflect the solar wind  enough so that it doesn't touch Mars.

地球なら他の種が空白を埋めるが 火星にその柔軟性はない

The easiest way is to construct a magnetic  umbrella far ahead of Mars that splashes the solar  

安定するまで数千とは言わないまでも 数百年はかかるだろう

wind to the sides. A big, superconducting ring  powered by nuclear facilities is all it takes.  

だがやがて大規模な 人類を維持できるようになる

It would orbit at the Mars-Sun L1  point, keeping it constantly in  

空気、水、食料が利用できるようになれば

between the Sun and Mars and protect  the new atmosphere. And that's it!

火星を故郷と呼べるようになる

Terraforming Mars would take some work,  hefty resources and probably a century or  

宇宙に浮かぶ巨大な火山島

ten but it would be the first time  we've lived in a home designed and  

長持ちするだろうか？

shaped solely by us and for us. A first  step towards our future among the stars.

挑戦その3 長期の未来

The first step we can already take  down on Earth is learning more about  

まだ対処してない問題がある 火星の核は磁場を持たず

the physics and biology needed for such a project.

宇宙からの放射線の 保護が十分ではない

To help you with that, we've created a series of  lessons to build your fundamental understanding  

これは火星人の健康によろしくないので

of these topics. Made in collaboration  with our friends at Brilliant.org,  

最後のステップは 人工の磁場が必要となるだろう

these lessons give you a deeper understanding  of the topics from our most popular videos,  

巨大なものはいらなくて

from supervolcanoes to black  holes to climate science.

太陽風が火星に当たらない程度に 曲げられればいい

Brilliant is an interactive learning tool  that makes math, science, and computer  

最も簡単な方法は火星の前に磁気の傘をつくって 太陽風をいなすものだ

science accessible with a hands-on approach.  Because we know that to really learn something,  

原子力発電で動く超伝導リングがいいだろう

you've got to do it. Think of each lesson as a  one-on-one tutoring version of a Kurzgesagt video.

火星と太陽のL1点に設置し

In our latest lesson, you'll learn more  about how Mars lost its atmosphere and  

新たな大気を保護させ続ける

how we might protect a terraformed  Mars from suffering the same fate.

よし完成だ

Brilliant has thousands of lessons to explore—from  math-based topics like algebra and probability  

火星の地球化は膨大な作業と資源が必要で 数百年はかかるだろう

to the concepts behind algorithms and machine  learning. And with new lessons added each month,  

しかしそれは自らのために 自ら設計した家に住む初の経験で

including ones from Kurzgesagt, you'll  always find something fascinating to learn.

星に囲まれた我らの未来への第一歩となるだろう

To get hands-on with Kurzgesagt lessons and  explore everything Brilliant has to offer,  

このような仕事に必要な学問を学ぶことが 地球上で出来る最初の一歩です

go to Brilliant.org/nutshell  and sign up for free today.  

我々はそのための基礎を学べる 一連のレッスンを作りました

There's even an extra perk for Kurzgesagt  viewers: the first 200 people to use the link  

Brilliant.org の協力による

get 20% off their annual membership, which  unlocks all of Brilliant's courses in math,  

人気の動画に登場する話題 例えばブラックホールや気象科学などを

science, and computer science. We love seeking new horizons with our  

より理解するためレッスンです

research – Brilliant will be the catalyst  to expand the limits of your knowledge.

Brilliant は学問を双方向的な方法で より身近に学ぶための学習ツールです