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  • Humans have observed comets for thousands of years

    人類は何千年もの間 肉眼で捉えられる

  • as their orbits have brought them within visible distance of Earth.


  • Appearing throughout historical records,


  • these mysterious lights that came out of nowhere

    この神秘的な光は どこからともなく現れ

  • and disappeared after a short while


  • were thought to be ill omens of war and famine,

    戦争や飢饉の前兆 あるいは

  • or the wrath of gods.


  • But recent research has revealed that comets may be even more deeply connected

    しかし 最近の研究によって 彗星は神話以上に もっと密接に

  • to humanity and our presence on Earth

    人類 とりわけ地球上での存在と

  • than any of these mythical explanations suggested.


  • When you think of our Solar System, you probably imagine the nine,

    太陽系について考える時 太陽の周りを回る9つ

  • sorry eight, planets orbiting the Sun.

    ―いや8つの― 惑星をおそらく連想されるでしょう

  • But beyond Neptune, far from the heat of the Sun,

    しかし 太陽の熱が届かない 海王星の外側には

  • there is a sparse ring found formed by icy chunks

    ビー玉くらいの大きさから 小惑星ほどの大きさまでの

  • ranging from the size of marbles to that of small planets.


  • And thousands of times farther at the outer reaches of the Solar System


  • lies a spherical cloud of small fragments and gases.


  • Many of these ancient clumps of stardust are leftovers from the formation

    これら古の星屑の多くは 46億年前に

  • of the Solar System 4.6 billion years ago,


  • while some of the most distant may even come from a neighboring system.

    最も遠くは 近隣の系から来るのもあります

  • But sometimes the gravity from passing planets or stars

    しかし時折 通過する惑星や 星の重力の影響で

  • pulls them toward our sun,


  • beginning a journey that can take up to millions of years.


  • As the frozen object travels further into the Solar System,

    凍った物体が 太陽系の中心部へと向かうにつれて

  • the sun grows from a distant spark to an inferno,

    遠くにある火花程度だった太陽が 猛火となり

  • melting the ice for the first time in billions of years.

    数十億年溶けなかった氷を 解かすのです

  • Gas and steam eject dust into space,


  • forming a bright surrounding cloud, called a coma,

    コマという輝く雲状のようなものを 周囲に形成します

  • that can grow even larger than the sun itself.

    コマは太陽よりも 遥かに大きく成長します

  • Meanwhile, the intense stream of high-energy particles

    一方 太陽風- 太陽から絶えず放出される

  • constantly emitted by the Sun, known as the solar wind,


  • blows particles away from the comet's core,


  • forming a trail of debris up to millions of miles long.


  • The ice, gas and dust reflect light glowing brightly.

    氷やガスや塵は光を反射し 明るく輝きます

  • A comet is born, now orbiting the sun along with the rest of the objects

    彗星が生まれると 太陽系の残りの天体と同じように

  • in our Solar System.


  • But as the comet travels through the Solar System,

    しかし 彗星が太陽系を移動する時に

  • the solar wind tears apart and recombines molecules into various compounds.

    太陽風が分子を引き裂き これが再結合して 様々な合成物になります

  • In some of the compounds that scientists found,


  • first in the rubble left by a meteorite that disintegrated above northern Canada,


  • and then in samples collected by a space craft from a passing comet's tail,

    宇宙探査機で 通り過ぎる彗星の尾から採取したサンプルでは

  • were nothing less important than amino acids.


  • Coming together to form proteins according to the instructs encoded in DNA,

    DNAの設計図に従い アミノ酸を集めてタンパク質が作られます

  • these are the main active components in all living cells,

    アミノ酸は バクテリアからシロナガスクジラまでの

  • from bacteria to blue whales.


  • If comets are where these building blocks of life were first formed,

    もし生命のこの構成要素が まず彗星で作られたのならば

  • then they are the ultimate source of life on Earth,


  • and, perhaps, some of the other places they visited as well.

    ひょっとすると 軌道上にある 他の惑星の生命の本源かもしれません

  • We know that planets orbit nearly every star in the night sky,

    夜空に見えるほとんどの恒星の周りを 惑星が回っていますが

  • with one in five having a planet similar to Earth in size and temperature.

    5つに1つが 規模や温度が地球に 似ている惑星なのです

  • If Earth-like planets and the molecules found in DNA are not anomalies,

    地球に似た惑星や DNAの分子が例外的ではないとしたら

  • we may be only one example of what's possible

    適切な条件下で 彗星の通過によって

  • when a planet under the right conditions is seeded with organic molecules

    有機分子が蒔かれた 可能性がある惑星として

  • by a passing comet.


  • So, rather than an omen of death,

    ですから 死の前兆というよりも

  • the comet that first brought amino acids to Earth


  • could have been a portent of life,


  • a prediction of a distant future, where creatures of stardust

    宇宙塵から創造された生物が遠い将来に その起源の謎を解き明かそうと

  • would return to space to find the mysteries of where they came from.

    宇宙に戻って探索することになるだろうという 予言であったのかもしれません

Humans have observed comets for thousands of years

人類は何千年もの間 肉眼で捉えられる


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B2 中上級 日本語 TED-Ed 彗星 太陽 惑星 アミノ 地球

TED-ED】彗星は地球の生命の源になりうるのか?- ジャスティン・ダウド (【TED-Ed】Could comets be the source of life on Earth? - Justin Dowd)

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    稲葉白兎 に公開 2021 年 01 月 14 日