如何阻止天外杀手撞击地球？(上)

What would happen if a gigantic asteroid started hurtling towards earth? [qh]

如果一颗巨大的小行星开始冲向地球会发生什么?[qh]

Would we all be headed for impending doom, like the dinosaurs some 66 million years ago?[qh]

我们会像6600万年前的恐龙一样濒临末日吗?[qh]

Well, we might not go the way of the dinosaurs after all. [qh]

嗯，我们可能不会重蹈恐龙的覆辙。[qh]

Last September NASA’s Double Asteroid Redirection Test, or DART—a spacecraft the size of a golf cart—smashed into a small asteroid called Dimorphos, actually altering its trajectory around another asteroid called Didymos in our first-ever test of planetary defense.[qh]

去年9月，在首次开展的行星防御测试中，美国宇航局的“双小行星重定向测试”(简称DART)——一艘高尔夫球车大小的航天器——撞向了一颗名为“迪莫弗斯”的小行星，居然改变了其围绕另一颗名为“迪迪莫斯”的小行星的轨道。[qh]

Oh my gosh. Oh wow. Awaiting individual confirmation. And we have impact! A triumph for humanity in the name of planetary defense![qh]

哦，我的天。等待个人确认。我们产生了冲击力! 以行星防御之名，人类取得了胜利![qh]

Hailed as a smashing success, no less than five studies in the scientific journal Nature get into the nitty-gritty of how exactly our celestial gut punch worked.[qh]

科学杂志《自然》上发表了至少五项被誉为轰动性成功的研究，这些研究深入揭示了天体沉重撞击到底是如何工作的。[qh]

What a moment. Very few words could capture this moment. Beautiful to watch.[qh]

多么美妙的一刻。几乎没有词语能描述这一刻。看起来真美。[qh]

I’m Tulika Bose, our senior multimedia editor at Scientific American.[qh]

我是图利卡·博斯，是《科学美国人》的高级多媒体编辑。[qh]

I’m here with Lee Billings, our senior editor for space and physics, who’ll try to answer some questions I’m sure we all have.[qh]

我和李·比林斯在一起，他是我们空间与物理学的资深编辑，他将试着回答一些我相信我们都有的问题。[qh]

Hey Lee.[qh]

嘿，李。[qh]

Hey Tulika.[qh]

嘿，图利卡。[qh]

Okay, so there’s a lot of stuff to sift through. [qh]

好，有很多东西要筛选。[qh]

One of the new studies details how this collision altered the path of Dimorphos through space—shortening the time it takes to orbit Didymos by 33 minutes. So, Lee, how did this work?[qh]

其中一项新研究详细描述了这次撞击如何改变了“迪莫弗斯”在太空中的路径——缩短了其进入“迪迪莫斯”轨道所需的时间，缩短了33分钟。那么，李，这是如何工作的呢?[qh]

Right. Ideally—and we’ll get into actuality in a moment—this is as simple as playing pool: shoot one billiard ball into another, and the target ball goes flying. [qh]

对。理想情况下——我们立刻举个现实例子——这就像打台球一样简单: 把一个台球射向另一个台球，目标台球就会飞起来。[qh]

The more momentum you can transfer, the more motion you get.[qh]

传递的冲击力越大，就能移动越多。[qh]

So you want to hit near dead center.[qh]

因此，你要击中死点附近。[qh]

And in DART’s case, it was targeted for the “leading” sunward side of Dimorphos, which it struck at a speed of more than 14,000 mph. [qh]

在“双小行星重定向测试”中， DART航天器的目标是“迪莫弗斯”的“主”向阳面，它以超过14000英里的时速撞向这颗小行星。[qh]

That’s about three quarters the speed of General Zod’s spaceship in Zach Snyder’s Man of Steel movie.[qh]

大约是扎克·斯奈德电影《超人：钢铁之躯》中查德将军的飞船速度的四分之三。[qh]

Now. Kneel before Zod.[qh]

现在到查德面前跪下。[qh]

Uh, okay. So now tell us about the two asteroids.[qh]

呃, 好吧。现在给我们讲讲这两颗小行星的情况。[qh]

Ah, yes, the two asteroids. Dimorphos is a moonlet of the bigger asteroid Didymos—sometimes I call Dimorphos “Didymoon” just because of that, right? [qh]

好，这两颗小行星。“迪莫弗斯”是体积更大的小行星“迪迪莫斯”的一个小卫星，有时因为这个，我会称“迪莫弗斯”为“迪迪卫星”。[qh]

That helps with gauging DART’s effects: think of Dimorphos a bit like the second hand on a clock where Didymos is the hour hand or the clock itself. [qh]

这有助于评估DART的效果: 将 “迪莫弗斯”想象成钟表上的秒针，“迪迪莫斯”想象成时针或钟表本身。[qh]

It’s easier to see small changes by watching how the smaller object moves.[qh]

通过观察较小物体的运动，更容易注意到微小变化。[qh]