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  • In the next 18 minutes, I'm going to take you on a journey.

    翻訳: Kazuyuki Shimatani 校正: Takako Sato

  • And it's a journey that you and I have been on for many years now,

    これからの18分間で 皆様を旅にお連れします

  • and it began some 50 years ago, when humans first stepped off our planet.


  • And in those 50 years, not only did we literally, physically set foot on the moon,

    約50年前 人類がこの惑星から最初の一歩を踏み出した時 この旅は始まりました

  • but we have dispatched robotic spacecraft to all the planets -- all eight of them --

    この50年の間に 文字通り 我々は月に足を下ろしただけではなく

  • and we have landed on asteroids, we have rendezvoused with comets,

    すべての惑星に無人探査機を送り込みました "8つ"全部にです

  • and, at this point in time, we have a spacecraft on its way to Pluto,

    小惑星に着陸し 彗星にも遭遇しました

  • the body formerly known as a planet.

    そして現在 冥王星へ探査機が向かっています

  • And all of these robotic missions are part of a bigger human journey:

    冥王星は 惑星であるとされていました

  • a voyage to understand something, to get a sense of our cosmic place,

    こういった無人探査はすべて 人類の壮大な旅の一部なのです

  • to understand something of our origins, and how Earth, our planet,

    この旅によって 宇宙について感じ取り 我々の起源や

  • and we, living on it, came to be.

    地球と そこに生きる我々が存在するようになった訳を

  • And of all the places in the solar system that we might go to


  • and search for answers to questions like this,

    これから我々が訪れ 探索を行おうとする この太陽系の

  • there's Saturn. And we have been to Saturn before --

    あらゆる場所が これらの疑問に対して答えてくれます

  • we visited Saturn in the early 1980s --

    土星です 土星には1980年代初頭に

  • but our investigations of Saturn have become far more in-depth in detail


  • since the Cassini spacecraft, traveling across interplanetary space

    今回は さらに詳細に渡った土星探査が可能になりました

  • for seven years, glided into orbit around Saturn in the summer of 2004,

    カッシーニ探査機は7年間 惑星間宇宙を旅して

  • and became at that point the farthest robotic outpost

    2004年の夏 土星の軌道に乗ることができたからです

  • that humanity had ever established around the Sun.


  • Now, the Saturn system is a rich planetary system.

    それは 人類が作り上げた 太陽を回る最前線の基地となったのです

  • It offers mystery, scientific insight and obviously splendor beyond compare,

    土星系は 豊かな星系です

  • and the investigation of this system has enormous cosmic reach.

    土星の神秘と科学的洞察 その荘厳さは比較できるものではありません

  • In fact, just studying the rings alone, we stand to learn a lot

    この星系を調査することで 宇宙に対する理解を深めることができます

  • about the discs of stars and gas that we call the spiral galaxies.

    土星の輪だけでも 我々が渦巻銀河と呼ぶ

  • And here's a beautiful picture of the Andromeda Nebula,


  • which is our closest, largest spiral galaxy to the Milky Way.


  • And then, here's a beautiful composite of the Whirlpool Galaxy,

    アンドロメダは 天の川銀河の最も近くにある最大の渦巻銀河です

  • taken by the Hubble Space Telescope.

    次は 子持ち銀河の美しい写真です

  • So the journey back to Saturn is really part of and is also a metaphor


  • for a much larger human voyage

    つまり土星への再訪は メタファーとしても

  • to understand the interconnectedness of everything around us,


  • and also how humans fit into that picture.

    我々を取り巻く全てのものが どのように結びつき

  • And it pains me that I can't tell you all that we have learned with Cassini.


  • I can't show you all the beautiful pictures that we've taken


  • in the last two and a half years, because I simply don't have the time.


  • So I'm going to concentrate on two of the most exciting stories


  • that have emerged out of this major exploratory expedition

    そこで もっとも興味深い話を二つしたいと思います

  • that we are conducting around Saturn,


  • and have been for the past two and a half years.


  • Saturn is accompanied by a very large and diverse collection of moons.


  • They range in size from a few kilometers across to as big across as the U.S.


  • Most of the beautiful pictures we've taken of Saturn, in fact,


  • show Saturn in accompaniment with some of its moons. Here's Saturn with Dione,


  • and then, here's Saturn showing the rings edge-on,

    衛星も一緒に写っています これはディオネを従えた土星です

  • showing you just how vertically thin they are, with the moon Enceladus.


  • Now, two of the 47 moons that Saturn has are standouts.

    いかに薄いものかお分かりいただけます エンケラドスが写っています

  • And those are Titan and Enceladus. Titan is Saturn's largest moon,


  • and, until Cassini had arrived there,

    これはタイタンとエンケラドスです タイタンは土星最大の衛星であり

  • was the largest single expanse of unexplored terrain


  • that we had remaining in our solar system.


  • And it is a body that has long intrigued people who've watched the planets.


  • It has a very large, thick atmosphere,

    この星は その姿を見た人々を長い間 魅了してきました

  • and in fact, its surface environment was believed to be


  • more like the environment we have here on the Earth,


  • or at least had in the past, than any other body in the solar system.


  • Its atmosphere is largely molecular nitrogen, like you are breathing here in this room,

    少なくとも かつては 太陽系の他の星よりも地球に似ていると考えられていたのです

  • except that its atmosphere is suffused with

    大気の大部分は窒素分子で構成されており この部屋で皆さんが呼吸しているものと同じものです

  • simple organic materials like methane and propane and ethane.

    相違点は その大気の中に

  • And these molecules high up in the atmosphere of Titan

    単純な有機物であるメタンやプロパン エタンを含んでいるということです

  • get broken down, and their products join together to make haze particles.

    そして これらの分子がタイタン大気圏の上層で

  • This haze is ubiquitous. It's completely global and enveloping Titan.

    分解され その結果生成された物質が結合して 煙霧粒子となっています

  • And that's why you cannot see down to the surface

    煙霧はタイタンのあらゆる場所に存在し 星を完全に覆い尽くしています

  • with our eyes in the visible region of the spectrum.


  • But these haze particles, it was surmised,


  • before we got there with Cassini, over billions and billions of years,

    しかし 煙霧の粒子については既に

  • gently drifted down to the surface and coated the surface

    カッシーニ探査機の到達以前に 予測されていました

  • in a thick organic sludge.

    何十億年もかけて 粒子がゆっくりと落下し 有機物でできた厚い泥で

  • So like the equivalent, the Titan equivalent, of tar, or oil, or what -- we didn't know what.


  • But this is what we suspected. And these molecules,

    いうなれば タイタンのタール あるいは石油 といったものが存在しているのです

  • especially methane and ethane, can be liquids at the surface temperatures of Titan.


  • And so it turns out that methane is to Titan what water is to the Earth.

    特にメタンやエタンの分子は タイタンの地表温度では液体となります

  • It's a condensable in the atmosphere,

    タイタンのメタンは 地球の水に相当する存在であることが分かりました

  • and so recognizing this circumstance brought to the fore


  • a whole world of bizarre possibilities. You can have methane clouds, OK,


  • and above those clouds, you have this hundreds of kilometers of haze,

    非常に奇妙な世界が存在している可能性にたどりつきます メタンの雲です

  • which prevent any sunlight from getting to the surface.

    そしてこの雲の上空何百キロにわたって 粒子が存在し

  • The temperature at the surface is some 350 degrees below zero Fahrenheit.


  • But despite that cold, you could have rain falling down on the surface of Titan.

    地表の気温は 零下210℃程度

  • And doing on Titan what rain does on the Earth: it carves gullies; it forms rivers

    これほどの低温下でも タイタンの地表には雨が降る可能性があります

  • and cataracts; it can create canyons; it can pool in large basins and craters.

    地球での雨と同じく タイタンでもこの雨が谷や川を形成し

  • It can wash the sludge off high mountain peaks and hills,

    滝もできます 峡谷を形成し 大規模な窪地やクレータに貯まることもあります

  • down into the lowlands. So stop and think for a minute.

    山頂や丘陵などの高地から 泥を

  • Try to imagine what the surface of Titan might look like.

    低地帯に押し流します ここで少し

  • It's dark. High noon on Titan is as dark as deep earth twilight on the Earth.


  • It's cold, it's eerie, it's misty,


  • it might be raining, and you might be standing

    寒く不気味で 霧でぼんやりして

  • on the shores of Lake Michigan brimming with paint thinner. (Laughter)


  • That is the view that we had of the surface of Titan before we got there with Cassini,


  • and I can tell you that what we have found on Titan, though it is not the same in detail,

    カッシーニ到着以前には タイタンの地表をこのように想像していました

  • is every bit as fascinating as that story is.

    今回 タイタンについて発見したことをお話しします 少し異なった状況を示していますが

  • And for us, it has been like -- the Cassini people --


  • it has been like a Jules Verne adventure come true.

    それはまるで カッシーニから見ると

  • As I said, it has a thick, extensive atmosphere.

    ジュール ベルヌの冒険物語が現実になったかのようです

  • This is a picture of Titan, backlit by the Sun, with the rings as a beautiful backdrop.


  • And yet another moon there --

    後方にある太陽に照らし出されたタイタンの写真です リングが美しい背景になっています

  • I don't even know which one it is. It's a very extensive atmosphere.

    そして 別の衛星が見えます

  • We have instruments on Cassini which can see down to the surface

    どの衛星かさえ分かりません 非常に厚い大気が存在しています

  • through this atmosphere, and my camera system is one of them.

    カッシーニには ツールが装備されていて

  • And we have taken pictures like this.

    この大気を通してでも地表まで見渡すことができます このカメラもそういったツールの一つです

  • And what you see is bright and dark regions, and that's about as far as it got for us.


  • It was so mystifying: we couldn't make out what we were seeing on Titan.

    明るい部分と暗い部分がありますが 可能な範囲を撮影しました

  • When you look closer at this region, you start to see things

    神秘に包まれており 何が見えているのか判断することができませんでした

  • like sinuous channels -- we didn't know. You see a few round things.

    この地域をよく見てみると 何かが見えてきます

  • This, we later found out, is, in fact, a crater,

    波状の水路のようですが よくは分かりません 丸い物がものが見えます

  • but there are very few craters on the surface of Titan,

    後に これがクレータだと判明しました

  • meaning it's a very young surface.

    しかしタイタンの表面には あまりクレータは存在しません

  • And there are features that look tectonic.


  • They look like they've been pulled apart.


  • Whenever you see anything linear on a planet,


  • it means there's been a fracture, like a fault.


  • And so it's been tectonically altered.

    それは 断層のような 裂け目の存在を意味します

  • But we couldn't make sense of our images,


  • until, six months after we got into orbit,


  • an event occurred that many have regarded


  • as the highlight of Cassini's investigation of Titan.

    そして そこで行われたイベントは

  • And that was the deployment of the Huygens probe,


  • the European-built Huygens probe that Cassini had carried

    そのイベントとは ホイヘンス観測機(プローブ)の投下です

  • for seven years across the solar system. We deployed it to the atmosphere of Titan,


  • it took two and a half hours to descend, and it landed on the surface.

    太陽系を7年間かけて運ばれ タイタンの大気中へ投下されました

  • And I just want to emphasize how significant an event this is.

    観測機は二時間半をかけて降下し 地表に降り立ちました

  • This is a device of human making,

    いかに素晴らしいイベントであったか ご理解いただきたいと思います

  • and it landed in the outer solar system for the first time in human history.


  • It is so significant that, in my mind,

    人類史上初めて 太陽系外縁部に着陸したのです

  • this was an event that should have been celebrated


  • with ticker tape parades in every city across the U.S. and Europe,


  • and sadly, that wasn't the case.

    紙吹雪のパレードを行って 成功を祝福されるべきものでした

  • (Laughter).

    残念ながら そうはなりませんでした

  • It was significant for another reason. This is an international mission,


  • and this event was celebrated in Europe, in Germany,

    これにはもう一つ重要な意味があります これは国際的なミッションであり

  • and the celebratory presentations were given in English accents,

    ヨーロッパ 特にドイツでも成功が祝されましたが

  • and American accents, and German accents, and French and Italian and Dutch accents.

    祝賀スピーチは 英国訛りや

  • It was a moving demonstration of what the words

    米国訛りや ドイツ語 フランス語 イタリア語 オランダ語訛りで行われました

  • "united nations" are supposed to mean:

    これは正に 「国際連合」という言葉

  • a true union of nations joined together in a colossal effort for good.


  • And, in this case, it was a massive undertaking to explore a planet,

    壮大な善き試みのために国々が協力する 真の連合です

  • and to come to understand a planetary system

    今回のケースでは その試みとは壮大な事業 つまり惑星を探査し

  • that, for all of human history, had been unreachable,


  • and now humans had actually touched it.


  • So it was -- I mean, I'm getting goose bumps just talking about it.

    そして 今 人類はそれを達成することができました

  • It was a tremendously emotional event,

    こうしてお話ししているだけで その興奮がよみがえってきます

  • and it's something that I will personally never forget, and you shouldn't either.


  • (Applause).

    私はこの出来事を一生忘れることはありません 皆様も同じだと思います

  • But anyway, the probe took measurements of the atmosphere on the way down,


  • and it also took panoramic pictures.

    とにかく 観測機は降下中に大気の組成を調査し

  • And I can't tell you what it was like to see the first pictures


  • of Titan's surface from the probe. And this is what we saw.

    最初の写真を見たときの事は 言葉にできません

  • And it was a shocker, because it was everything we wanted


  • those other pictures taken from orbit to be.

    衝撃的な写真でした なぜなら 我々が

  • It was an unambiguous pattern, a geological pattern.


  • It's a dendritic drainage pattern that can be formed only by the flow of liquids.

    はっきりとしたパターン 地質学的なパターンが見られます

  • And you can follow these channels

    この樹木状の排水路のようなものは 液体が流れた時のみ形成される図形です

  • and you can see how they all converge.


  • And they converge into this channel here, which drains into this region.


  • You are looking at a shoreline.

    この水路に合流して この地域に流れ出ます

  • Was this a shoreline of fluids? We didn't know.


  • But this is somewhat of a shoreline.


  • This picture is taken at 16 kilometers.


  • This is the picture taken at eight kilometers, OK? Again, the shoreline.


  • Okay, now, 16 kilometers, eight kilometers -- this is roughly an airline altitude.

    これは8km上空で 再び海岸線です

  • If you were going to take an airplane trip across the U.S.,

    16km 8km つまり航空機が飛ぶ高度と同じくらいです

  • you would be flying at these altitudes.


  • So, this is the picture you would have at the window of Titanian Airlines