suddenly appeared near you?

結果的に あなたは死ぬ

Short answer: you’d die.

だが死に方はブラックホール次第だ

Long answer: it depends.

コイン程度の質量が

Is it a black hole with the mass of a coin,

ブラックホールになった場合

or is it as wide as a coin?

その半径は10の－30乗メートル

Suppose a US nickel with the mass of about 5 grams

原子は10の－11乗メートルだから

magically collapsed into a black hole.

太陽に対する原子ぐらい

This black hole would have a radius of about 10 to the power of −30 meters.

原子よりも小さい

By comparison, a hydrogen atom is about 10 to the power of −11 meters.

そしてホーキング放射により

So the black hole compared to an atom is as small as

存在する時間もとても短い

an atom compared to the Sun.

10の－23乗秒で質量は消えてしまう

Unimaginably small!

その時出るエネルギーは

And a small black hole would also have an unimaginably short lifetime

450テラジュール

to decay by Hawking radiation.

広島と長崎に落ちた爆弾を

It would radiate away what little mass it has in 10 to the power of −23 seconds.

合計して３倍した大きさだ

Its 5 grams of mass will be converted to 450 terajoules of energy,

これであなたは死ぬ

which will lead to an explosion roughly 3 times bigger than

コインも消える

the atomic bombs dropped on Hiroshima and Nagasaki combined.

ブラックホールの大きさが

In this case, you die.

コイン程度だった場合は

You also lose the coin.

その質量は地球よりも大きくなる

If the black hole had the diameter of a common coin,

そしてその重力は

then it would be considerably more massive.

地球の100京倍もある

In fact, a black hole with the diameter of a nickel

受ける引力が強すぎて

would be slightly more massive than the Earth.

体は細胞単位に引き裂かれ

It would have a surface gravity a billion billion times greater

一瞬で飲み込まれるだろう

than our planet currently does.

また 同じ重力ではあるが

Its tidal forces on you would be so strong

これは経験したことのない重力だ

that they’d rip your individual cells apart.

重力は 宇宙全体にまで及ぶ力であり

The black hole would consume you before you even realized what’s happening.

離れていくほど弱くなる

Although the laws of gravity are still the same,

地上では あなたの頭と足は

the phenomenon of gravity that you’d experience would be very different

中心からほぼ等距離だ

around such dense objects.

だがブラックホールに立った場合

The range of the gravitational attraction

足は頭の100倍近いため

extends over the entire observable universe,

引力は１万倍にもなり

with gravity getting weaker the farther away you are from something.

足から粉々に砕かれていくだろう

On Earth right now, your head and your toes are approximately the same distance

それだけじゃ済まない

from the center of our planet.

このブラックホールには

But if you stood on a nickel-sized black hole,

地球よりも大きな力がある

your feet would be hundreds of times closer to the center,

ブラックホールは中心に落ちて

and the gravitational force would be tens of thousands of times as large

地球を飲み込むだろうか

as the force on your head and rip you into a billion pieces.

いや実際は地球も動くから

But the black hole wouldn’t stop with just you.

地球の中心を周りながら

The black hole is now a dominant gravitational piece

通過したところを飲み込んでいく

of the Earth–Moon–Black-Hole-of-Death system.

内側が食べ尽くされると

You might think that the black hole would sink towards the center of the planet

熱い溶岩の塵が円盤状に残される

and consume it from the inside out.

ブラックホールは質量が倍になり

In fact, the Earth also moves up onto the black hole and begins to bob around,

月の軌道は楕円形になる

as if it were orbiting the black hole,

太陽系にも影響する

all while having swathes of mass eaten with each pass,

つまり ひどいことになる

which is much more creepy.

ブラックホールが小惑星を引っ張り

As the Earth is eaten up from the inside,

大量の岩を太陽系になだれ込ませる

it collapses into a scattered disk of hot rock,

以後数百万年は 爆発と衝撃だらけだ

surrounding the black hole in a tight orbit.

惑星も力を受けるが軌道は変わらず

The black hole slowly doubles its mass by the time it’s done feeding.

ブラックホールも地球に代わり

The Moon’s orbit is now highly elliptical.

同じ軌道を周る

The effects on the Solar system are awesome—

そうして あなたは死ぬ

in the Biblical sense of awesome, which means terrifying.

Subtitles by the Amara.org community

Tidal forces from the black hole would probably disrupt the near-Earth asteroids,

maybe even parts of the asteroid belt,

sending rocks careening through the Solar system.

Bombardment and impacts may become commonplace

for the next few million years.

The planets are slightly perturbed, but stay approximately in the same orbit.

The black hole we used to call Earth will now

continue on orbiting the Sun in the Earth’s place.

In this case, you also die.

This bonus video was made possible by your contributions on Patreon.

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The topic is based on a question on the AskScience subreddit

and the glorious answer by Matt [Caplin?], who also worked with us on this video.

Check out his blog, Quarks and Coffee, for more awesome stuff like this!

If you want to discuss the video, we have our own subreddit now.

To learn more about black holes or equally interesting neutron stars, click here.

Subtitles by the Amara.org community