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  • I want to talk to you about something

    翻訳: Yuko Masubuchi 校正: Wataru Narita

  • kind of big.

    話しておきたい事があります

  • We'll start here.

    重要な話です

  • Sixty-five million years ago --

    始めましょう

  • (Laughter)

    6500万年前

  • the dinosaurs had a bad day.

    恐竜達には不運な1日でした

  • (Laughter)

    (笑)

  • A chunk of rock six miles across,

    直径10キロの大きな隕石が

  • moving something like 50 times the speed of a rifle bullet,

    ライフル銃の

  • slammed into the Earth.

    約50倍の速さで

  • It released its energy all at once,

    地球に衝突しました

  • and it was an explosion that was mind-numbing.

    そのエネルギーは一瞬で放射され

  • If you took every nuclear weapon ever built

    大爆発し

  • at the height of the Cold War,

    全てが終わりました

  • lumped them together,

    冷戦の最中に造られた

  • and blew them up at the same time,

    全ての核兵器を

  • that would be one one-millionth of the energy released at that moment.

    集めて一度に

  • The dinosaurs had a really bad day.

    爆発させたとしても

  • OK?

    その隕石が衝突した時の

  • Now, a six-mile-wide rock is very large.

    100万分の1のエネルギーにしかなりません

  • We all live here in Boulder.

    恐竜達には本当に不運な1日でした

  • If you look out your window and see Longs Peak --

    いいですか?

  • you're probably familiar with it --

    直径10キロの隕石は非常に大きいです

  • now, scoop up Longs Peak and put it out in space.

    我々はボルダーに住んでいます

  • Take ... Meeker, Mt. Meeker.

    窓の外の

  • Lump that in there, and put that in space as well.

    ロングスピークは 見慣れた景色です

  • And Mt. Everest. And K2.

    では ロングスピークをすくい上げて

  • And the Indian peaks.

    脇に置いておきます

  • Then you're starting to get an idea of how much rock we're talking about, OK?

    ミーカー山もとって1つにまとめて

  • We know it was that big

    エベレストとK2(山)

  • because of the impact it had and the crater it left.

    インディアンピークスも

  • It hit in what we now know as Yucatan, the Gulf of Mexico.

    一緒にしておきます

  • You can see here, there's the Yucatan Peninsula,

    では考えてみましょう

  • if you recognize Cozumel off the east coast there.

    いくつの山について話しましたか?

  • Here is how big of a crater was left.

    その隕石が巨大だったのは

  • It was huge.

    その衝撃やクレーターから明らかです

  • To give you a sense of the scale ... there you go.

    隕石が落ちたのは

  • The scale here is 50 miles on top, a hundred kilometers on the bottom.

    メキシコ湾のユカタンです

  • This thing was 300 kilometers across -- 200 miles --

    こちらに見えるのが

  • an enormous crater that excavated out vast amounts of earth

    ユカタン半島です コスメル島は

  • that splashed around the globe and set fires all over the planet,

    東海岸から離れたところにあります

  • threw up enough dust to block out the sun.

    クレーターの大きさが見てとれますね

  • It wiped out 75 percent of all species on Earth.

    巨大でした 規模を測ると

  • Now, not all asteroids are that big.

    こちらですが

  • Some of them are smaller.

    大きさは頂上が80キロで

  • Here is one that came in

    ふもとは100キロです

  • over the United States in October of 1992.

    直径300キロ(約200マイル)の

  • It came in on a Friday night.

    巨大なクレーターは

  • Why is that important?

    大量の大地を削って世界中に撒き散らし

  • Because back then, video cameras were just starting to become popular,

    日光を遮る程の粉じんと共に

  • and parents would bring them to their kids' football games

    地球全体を火の海にしてできました

  • to film their kids playing football.

    地球上の全生物の75パーセントが

  • And since this came in on a Friday,

    絶滅しました

  • they were able to get this great footage of this thing breaking up

    全ての小惑星がこんなに大きい訳ではなく

  • as it came in over West Virginia, Maryland, Pennsylvania and New Jersey

    小さいものもあります

  • until it did that

    これは

  • to a car in New York.

    1992年10月に

  • (Laughter)

    アメリカに落下した隕石です

  • Now, this is not a 200-mile-wide crater,

    金曜日の夜でした

  • but then again, you can see the rock, which is sitting right here,

    なぜそれが重要か?

  • about the size of a football,

    当時ビデオカメラは

  • that hit that car and did that damage.

    普及し始めたばかりで

  • Now, this thing was probably about the size of a school bus

    誰もがビデオカメラを携帯し

  • when it first came in.

    子供達のフットボールの試合を撮りました

  • It broke up through atmospheric pressure,

    金曜日に落下したことで

  • it crumbled, and then the pieces fell apart

    この素晴しい映像が各地で撮影されました

  • and did some damage.

    ウエストヴァージニア

  • Now, you wouldn't want that falling on your foot or your head,

    メリーランド ペンシルバニア

  • because it would do that to it.

    ニュージャージー

  • That would be bad.

    ニューヨークの車にまで

  • But it won't wipe out, you know, all life on Earth, so that's fine.

    (笑)

  • But it turns out, you don't need something six miles across

    これは直径300キロもありませんね

  • to do a lot of damage.

    しかしここにあるような

  • There is a median point between tiny rock and gigantic rock,

    フットボール位の隕石でも

  • and in fact, if any of you have ever been to near Winslow, Arizona,

    ぶつかると

  • there is a crater in the desert there that is so iconic

    車が損傷しています

  • that it is actually called "Meteor Crater."

    この隕石は恐らく元々は

  • To give you a sense of scale, this is about a mile wide.

    スクールバス程の大きさでした

  • If you look up at the top, that's a parking lot,

    それが大気圧で砕けて

  • and those are recreational vehicles right there.

    粉々になり かけらが落下して

  • So it's about a mile across, 600 feet deep.

    被害を与えたのでしょう

  • The object that formed this was probably about 30 to 50 yards across,

    こんな隕石が足や頭の上に落ちてきたら

  • so roughly the size of Macky Auditorium here.

    大変なことになりますね

  • It came in at speeds that were tremendous,

    最悪でしょう

  • slammed into the ground, blew up,

    しかし地球上の全ての生命が

  • and exploded with the energy of roughly a 20-megaton nuclear bomb --

    絶滅する事は無いので大丈夫です

  • a very hefty bomb.

    しかし直径10キロ無くても

  • This was 50,000 years ago,

    大災害は起こり得るのです

  • so it may have wiped out a few buffalo or antelope,

    隕石には小さなものと大きなものだけでなく

  • or something like that out in the desert,

    中ぐらいの大きさを持つものもあります

  • but it probably would not have caused global devastation.

    アリゾナのウィンズローに行くと

  • It turns out that these things don't have to hit the ground

    砂漠の中に”アリゾナ隕石孔”と呼ばれる

  • to do a lot of damage.

    非常に象徴的なクレーターがあります

  • Now, in 1908, over Siberia, near the Tunguska region --

    規模を測ると 直径1.5キロです

  • for those of you who are Dan Aykroyd fans and saw "Ghostbusters,"

    頂上は駐車場になっています

  • when he talked about the greatest cross-dimensional rift

    RV車も停まっています

  • since the Siberia blast of 1909,

    直径約1,5キロで深さ200メートルです

  • where he got the date wrong, but that's OK.

    この隕石孔を形成した物体の大きさは

  • (Laughter)

    およそ30~45メートル程で

  • It was 1908. That's fine. I can live with that.

    このマッケイ公会堂位のサイズです

  • (Laughter)

    それは驚異的な速さでやって来て

  • Another rock came into the Earth's atmosphere

    地面に衝突し 粉々になり

  • and this one blew up above the ground,

    およそ20メガトンの核爆弾のエネルギーで

  • several miles up above the surface of the Earth.

    爆発しました

  • The heat from the explosion set fire to the forest below it,

    非常に大きな爆弾です

  • and then the shock wave came down and knocked down trees

    5万年前にその隕石は

  • for hundreds of square miles.

    バッファローかアンテロープの様な生物を

  • This did a huge amount of damage.

    砂漠から絶滅させました

  • And again, this was a rock probably roughly the size

    しかし地球規模の災害の原因には

  • of this auditorium that we're sitting in.

    ならなかった様ですね

  • In Meteor Crater, it was made of metal,

    次の事例からは小惑星が衝突しなくても

  • and metal is much tougher, so it made it to the ground.

    大災害が起こる事が分かります

  • The one over Tunguska was probably made of rock,

    1908年のツングースカ大爆発ですが

  • and that's much more crumbly, so it blew up in the air.

    ”ゴーストバスターズ”を観ると

  • Either way, these are tremendous explosions -- 20 megatons.

    ダン・エイクロイドが

  • Now, when these things blow up,

    1909年のツングースカ大爆発以来の

  • they're not going to do global ecological damage.

    超常現象だと言いますが

  • They're not going to do something like the dinosaur killer did.

    間違っていますね 1908年です

  • They're just not big enough.

    大丈夫 間違ってても生きていけます

  • But they will do global economic damage,

    (笑)

  • because they don't have to hit, necessarily,

    この時小惑星は大気圏に入ると

  • to do this kind of damage.

    地上から数キロ上空で

  • They don't have to do global devastation.

    爆発しました

  • If one of these things were to hit pretty much anywhere,

    爆発による高熱で

  • it would cause a panic.

    森は炎上し その空振で

  • But if it came over a city, an important city --

    数千平方キロメートルの木々が

  • not that any city is more important than others,

    なぎ倒されました

  • but some of them we depend on more on the global economic basis --

    これは非常に大きな破壊規模でした

  • that could do a huge amount of damage to us as a civilization.

    繰り返しますが これは恐らく

  • So, now that I've scared the crap out of you --

    この公会堂位の小惑星の仕業でしょう

  • (Laughter)

    アリゾナ隕石孔は鉄金を成分とした

  • what can we do about this?

    とても頑丈な隕石が衝突した事で

  • This is a potential threat.

    形成されました

  • Let me note that we have not had a giant impact like the dinosaur killer

    ツングースカについては恐らく

  • for 65 million years.

    とても砕けやすい小惑星の仕業で

  • They're very rare.

    それ故に空中分解しました

  • The smaller ones happen more often,

    いずれの事例も20メガトンの大爆発でした

  • but probably on the order of a millennium,

    この位の規模の爆発では

  • every few centuries or every few thousand years.

    地球規模で生態系に影響を及ぼすことはないでしょう

  • But it's still something to be aware of.

    恐竜が絶滅したような事態には

  • Well, what do we do about them?

    ならないでしょう

  • The first thing we have to do is find them.

    それ程の破壊力はありません

  • This is an image of an asteroid that passed us in 2009.

    しかし世界経済には損失を与えます

  • It's right here.

    地表に衝突しなかったとしても

  • But you can see that it's extremely faint.

    損失が出ることがあります

  • I don't know if you can see that in the back row.

    地球規模の惨事になる必要はありません

  • These are just stars.

    もし隕石がどこかに落ちてくるとしたら

  • This is a rock that was about 30 yards across,

    パニックを引き起こすでしょう

  • so roughly the size of the ones that blew up over Tunguska

    もしこれが最も重要な都市―

  • and hit Arizona 50,000 years ago.

    どの都市もそれぞれ重要ですが

  • These things are faint.

    世界経済を支えている都市に

  • They're hard to see, and the sky is really big.

    隕石が降ったとすると

  • We have to find these things first.

    我々の文明や生活に大きな影響が

  • Well, the good news is, we're looking for them.

    あるでしょう

  • NASA has devoted money to this;

    みなさん怖くなって震えてますね

  • the National Science Foundation and other countries

    (笑)

  • are interested in doing this.

    我々に何ができるでしょう?

  • We're building telescopes that are looking for the threat.

    これは潜在的脅威です

  • That's a great first step. But what's the second step?

    この6500万年の間 恐竜が絶滅したような

  • The second step is if we see one heading toward us, we have to stop it.

    巨大衝突は起きていません

  • What do we do?

    めったに無い事です

  • You've probably heard about the asteroid Apophis.

    小さな隕石の衝突はしばしば起きますが

  • If you haven't yet, you will.

    恐らくは1000年周期

  • If you've heard about the Mayan 2012 apocalypse,

    数世紀から数千年に一度の出来事です

  • you're going to hear about Apophis,

    それでも注意を向けるべき事です

  • because you're keyed in to all the doomsday networks, anyway.

    さて 我々はどうしましょう?

  • (Laughter)

    まずは見つける事です

  • Apophis is an asteroid that was discovered in 2004.

    これは2009年に地球の近くを通った

  • It's roughly 250 [meters] across, so it's pretty big --

    小惑星です

  • bigger than a football stadium.

    ここです

  • And it's going to pass by the Earth in April of 2029.

    とても見えづらいでしょう

  • And it's going to pass us so close

    後方にあるものが見えるでしょうか

  • that it's actually going to come underneath our weather satellites.

    これらはただの星です

  • The Earth's gravity is going to bend the orbit of this thing so much

    直径30メートル位なので

  • that if it's just right,

    ツングースカやアリゾナに衝突した

  • if it passes through this region of space,

    物体とほぼ同じ大きさでしょう

  • this kidney-bean-shaped region called the keyhole,

    かすかにしか見えません

  • the Earth's gravity will bend it just enough that seven years later,

    見えづらい上に 空は広大です

  • on April 13 -- which is a Friday, I'll note -- in the year 2036 --

    我々はこれらを見逃してはなりません

  • (Laughter)

    幸いな事に 我々は常に見張っています

  • you can't plan that kind of stuff --

    NASAはこの監視に予算を充てています

  • (Laughter)

    アメリカ国立科学財団や諸外国は

  • Apophis is going to hit us.

    この事にとても関心を持っています

  • And it's 250 meters across, so it would do unbelievable damage.

    これらの脅威を見つけ出すために

  • The good news is that the odds of it actually passing through this keyhole

    我々は望遠鏡を作っています

  • and hitting us next go-around are one in a million, roughly --

    重要な第一歩です 次に行う事は

  • very, very low odds.

    地球に向かってきている物体を確認し

  • So I personally am not lying awake at night worrying about this at all.

    食い止める事です 何をするか?

  • I don't think Apophis is a problem.

    小惑星アポフィスをご存知でしょう

  • In fact, Apophis is a blessing in disguise,

    知らなくてもいつか耳にします

  • because it woke us up to the dangers of these things.

    2012年のマヤの予言についてご存知なら

  • This thing was discovered just a few years ago

    アポフィスを知る事になるでしょう

  • and could hit us a few years from now.

    地球の終末についての情報は

  • It won't, but it gives us a chance to study these kinds of asteroids.

    互いに結び付いているのですから

  • We didn't really necessarily understand these keyholes, and now we do,

    アポフィスは2004年に発見されました

  • and it turns out that's really important,

    直径およそ250メートルの大きさで

  • because how do you stop an asteroid like this?

    かなり大きいですね

  • Well, let me ask you:

    フットボール競技場よりも大きい物体が

  • What happens if you're standing in the road and a car's headed for you?

    2029年4月に地球の近くを通過します

  • What do you do?

    どれ程近くかというと

  • You do this. Right? Move, and the car goes past you.

    気象衛星よりも近くを通ると

  • But we can't move the Earth, at least not easily,

    思われています

  • but we can move a small asteroid.

    地球の引力はアポフィスの軌道を

  • And it turns out, we've even done it.

    曲げてしまいます

  • In the year 2005, NASA launched a probe called Deep Impact,

    もしアポフィスが この豆型の

  • which slammed a piece of itself into the nucleus of a comet.

    ”鍵穴”とよばれる場所を通過すると

  • Comets are very much like asteroids.

    地球の重力で軌道が変わり

  • The purpose wasn't to push it out of the way;

    そうすると

  • the purpose was to make a crater to excavate the material

    7年後の2036年4月13日には…

  • and see what was underneath the surface of this comet,

    ちなみに13日の金曜日ですね(笑)

  • which we learned quite a bit about.

    ―天体の動きに計画は立てられません―

  • We did move the comet a little tiny bit --

    アポフィスが地球に衝突するでしょう

  • not very much, but that wasn't the point.

    それは直径250メートルで

  • However, think about this:

    衝撃は想像を超えるでしょう

  • This thing is orbiting the Sun at 10, 20 miles per second.

    幸いな事に その確率ですが

  • We shot a space probe at it and hit it, OK?

    鍵穴を通過して

  • Imagine how hard that must be, and we did it.

    地球に衝突する確率は100万分の1です

  • That means we can do it again.

    とても低い確率でなので個人的には

  • If we see an asteroid that's coming toward us, headed right for us,

    心配で夜眠れない様な事はありません

  • and we have two years to go?

    アポフィスは問題ではありません

  • Boom! We hit it.

    アポフィスは不幸中の幸いです

  • You know, if you watch the movies --

    こうしたことに対する我々の危機意識を

  • (Laughter)

    目覚めさせたからです

  • you might think:

    これはたった数年前に発見されたもので

  • Why don't we use a nuclear weapon?

    数年後に衝突することもあり得ました

  • Well, you can try that, but the problem is timing.

    実際には衝突しませんがこれを機に

  • Shoot a nuclear weapon at this thing,

    この類の小惑星の調査が始まりました

  • you have to blow it up within a few milliseconds of tolerance,

    以前は鍵穴のことなどわかりませんでしたが

  • or else you'll miss it.

    今はわかっています

  • And there are a lot of other problems with that; it's very hard to do.

    小惑星の衝突をどう食い止めるかにおいて

  • But just hitting something? That's pretty easy.

    これはとても重要です

  • I think even NASA can do that, and proved that they can.

    お尋ねしますが

  • (Laughter)

    もし道路の真ん中に立っていて

  • The problem is, if you hit this asteroid, you've changed the orbit,

    車がこちらに向かってきたらどうしますか?

  • you measure the orbit,

    よけるでしょう?車は通過します

  • then you find out, oh yeah, we just pushed it into a keyhole,

    地球は簡単に動きません

  • and now it's going to hit us in three years.

    しかし小惑星なら動かせます

  • Well, my opinion is: fine!

    それはもう実際に行われています

  • It's not hitting us in six months --

    2005年にNASAは”ディープインパクト”という

  • that's good.

    探査機を打ち上げ その一部分を

  • Now we have three years to do something else.

    彗星の核に衝突させました

  • And you can hit it again.

    彗星は小惑星によく似ています

  • That's kind of ham-fisted;

    目的は軌道を変えることではありませんでした

  • you might just push it into a third keyhole or whatever,

    目的はクレーターを作り