Atoms, stars and galaxies, planets and trees, rocks and us.

それは原子や星々

This matter accounts for less than 5% of the known universe.

惑星や木 岩や私たちのことだ

About 25% is dark matter; and 70% is dark energy.

だがこれらは全体の５％でしかなく

Both of which are invisible.

25％がダークマター

This is kind of strange because it suggests that everything we experience is

70％がダークエネルギーだ

really only a tiny fraction of reality.

両方とも目に見えない

But it gets worse.

どうやら私たちが経験しているのは

We really have no clue what dark matter and energy are, or how they work.

現実のごく一部分だけのようだ

We are pretty sure they exist though.

ダークマターやダークエネルギーは

So, what do we know?

正体がまだ不明で

Dark matter is the stuff that makes it possible for galaxies to exist.

その証拠も少ない

When we calculated why the universe is structured the way it is,

その話をしていこう

it quickly became clear that there's just not enough normal matter.

ダークマターは

The gravity of the visible matter is not strong enough to form

銀河の存在に必要な物質だ

galaxies and complex structures.

銀河の構造について計算すると

The stars would more likely be scattered all over the place and not form galaxies.

普通の物質だけでは不足が出る

So, we know there is something else inside and around them.

見える物質の重力だけでは

Something that doesn't emit or reflect light.

銀河の構造は作れない

Something dark...

星が散らばってしまい

but besides being able to calculate the existence of dark matter,

銀河とならないのだ

we can see it... kind of.

つまりその中か周囲には何かがある

Places with a high concentration of dark matter bend light passing near by.

光を出さず 反射もしない

So we know there's something there that interacts with gravity.

何か 暗いものが

Right now, we have more ideas about what dark energy is not, than what it is!

その何かは計算することにより

We know dark matter is not just clouds of normal matter without stars,

少しは見えてくる

because it would emit particles we could detect.

密集したダークマターは

Dark matter is not anti-matter,

近くの光を曲げる

because anti-matter produces unique gamma rays when it reacts with normal matter.

何やら重力的な力があるようだ

Dark matter is also not made up of black holes,

今 ダークマターでわかっているのは

very compact objects that violently affect their surroundings,

それが何でないかだ

while dark matter seems to be scattered all over the place.

ダークマターは粒子の雲ではない

Basically, we only know 3 things for sure;

粒子なら検出できるはずだ

1. Something is out there.

ダークマターは反物質ではない

2. It interacts with gravity.

反物質ならガンマ線を出すはずだ

3. There is a lot of it.

ブラックホールでもないだろう

Dark matter is probably made up of a complicated exotic particle

周囲に影響を及ぼしているが

that doesn't interact with light and matter in a way we expect,

ブラックホールほどひどくはない

but right now, we just don't know.

今わかっているのは３つだ

Dark energy is even more strange and mysterious.

１. 何かが存在する

We can't detect it, we can't measure it and we can't taste it.

２. 重力的な力がある

But we do see its effects very clearly.

３. たくさんある

In 1929, Edward Hubble examined how the wavelength of light

何か光を受けないような

emitted by distant galaxies, shifts towards the red end

未知の粒子があるのかもしれないが

of the electromagnetic spectrum as it travels through the space.

今はまだわからない

He found that fainter, more distant galaxies showed a large degree of red shift;

ダークエネルギーはもっと謎だ

closer galaxies, not so much.

検出できず 測定できず 味わえない

Hubble determined that this was because the universe itself is expanding.

だがその影響は確かにある

The red shift occurs, because the wavelengths of light

1929年 ハッブルは

are stretched as the universe expands.

銀河からやってくる光の波長を調べ

More recent discoveries have shown that, the expansion of the universe is accelerating.

それが赤い方に寄る現象を発見した

Before that, it was thougth that the pull of gravity would cause the expansion to

その赤方への偏移の度合いは

either slow down or even retract and collapse in on itself at some point.

遠い銀河ほど大きく

Space doesn't change its properties as it expands; there's just more of it.

近くでは小さかった

New space is constantly created everywhere,

彼は宇宙の膨張が原因だと結論した

galaxies are tight bound clusters of stuff held together by gravity

偏移が起こるのは

so we don't experience this expansion in our daily lives.

空間の拡張が波長を伸ばすからだと

But we see it everywhere around us.

最新の観測では

Wherever there is empty space in the universe, more is forming every second.

宇宙の膨張は加速度的だ

So, dark energy seems to be some kind of energy intrinsic to empty space.

以前は 宇宙の膨張は徐々に遅くなり

Energy that is stronger than anything else we know

将来 収縮していくと考えられていた

and it keeps getting stronger as time passes by.

空間は 性質を変えることなく

Empty space has more energy than everything else in the universe combined.

ただ広がる

We have multiple ideas about what dark energy might be.

空間は次々に生まれている

One idea is, the dark energy is not a thing, but just a property of space.

銀河では重力が強く働いているから

Empty space is not nothing, it has its own energy.

それを感じることはない

It can generate more space and is quite active.

だがそこら中で

So, as the universe expands, it could be that just more and more space

新しい空間が常に生まれ続けている

appears to fill the gaps and this leads to a faster expanding universe.

ダークエネルギーは

This idea is close to an idea that Einstein had back in 1917,

空間の性質なのだろうか

of the concept of a cosmological constant,

この宇宙一強い力は

a force that counteracted the force of gravity.

時間が経つほど力を増す

The only problem is, that when we tried to calculate the amount of this energy

何もないただの空間に

the result was so wrong and weird, that it only added to the confusion.

全物質より大きな力がある

Another idea is, that empty space is actually full of

これにはいくつかの説が考えられる

temporary, virtual particles that spontaneously and continually

ダークエネルギーは物ではなく

form from nothing and then dissapear into nothing again.

空間の性質とする説

The energy form those particles could be dark energy.

空間自体にエネルギーが存在し

Or maybe dark energy is an unknown kind of dynamic energy fluid or field

それが活発に活動している

which permeates the entire universe, but somehow has the opposite effect

宇宙が広がるほど

on the universe than normal energy and matter.

空間は増えていくことになるから

But if it exists, we don't know how and where or how we could detect it.

加速が生まれるのだという説だ

So there are still a lot of questions to answer.

これはアインシュタインが考えた

Our theories about dark matter and dark energy are still just that;

重力に反する力という

theories.

宇宙定数の概念に近い

On one hand, this is kind of frustrating, on the other hand this is frontier science

問題はそれを計算しようとすると

making it very exciting.

おかしな結果になってしまうことだ

It shows us that no matter how much we feel we're on top of things,

また別の説では 空間は

we are still very much apes with smartphones, on a tiny

生まれ続ける粒子で満ちていて

fragile island in space looking into the sky wondering how our universe works

現れてはすぐに消えるのだと言う

There is so much left to learn, and that is awesome.

これがエネルギーの正体だろうか

This video is supported by the Australian Academy of Science,

またダークエネルギーは

which promotes and supports excellence in science.

宇宙全体に満ちた未知の力であり

Learn more about this topic and others like it at nova.org.au.

通常の力とは異なるという説もある

It was a blast of work with them so go check out their site.

その場合

Our videos are also made possible by your support on patreon.com,

その存在を確かめる方法はない

if you want to support us and become part of the Kurzgesagt Bird Army,

まだまだ疑問はたくさんある

check out our patreon page.

これらの理論はまだ

Subtitles by the Amara.org community

ただの理論だ