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

如果一颗巨大的小行星开始冲向地球会发生什么?

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

我们会像6600万年前的恐龙一样濒临末日吗?

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

嗯，我们可能不会重蹈恐龙的覆辙。

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!

嘿，图利卡。

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

好，有很多东西要筛选。

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?

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?

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. 

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.

The more momentum you can transfer, the more motion you get.

传递的冲击力越大，就能移动越多。

So you want to hit near dead center.

因此，你要击中死点附近。

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.

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。

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

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。

Now. Kneel before Zod.

现在到查德面前跪下。

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

呃, 好吧。现在给我们讲讲这两颗小行星的情况。

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

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”。

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. 

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。

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

通过观察较小物体的运动，更容易注意到微小变化。

So to look at how amazing this is, let’s take a look at the size of Dimorphos. How big is it, exactly?And how far away was it?

为了看看这次撞击有多神奇，我们来看看“迪莫弗斯”的大小。这颗小行星到底有多大? 距离有多远?

So Dimorphos is about as big and heavy as the Great Pyramid. It’s also about as big as the Roman Colosseum.

“迪莫弗斯”与大金字塔一样大，一样重。与罗马斗兽场也一样大。

Okay, that’s pretty big.

好吧，体积相当大。

But for those of us steeped in modernity, I like just to say it's about twice the size of a standard football field, and it weighed an estimated 11 billion pounds.

不过，对于我们这些沉浸在现代生活中的人来说，我会说，“迪莫弗斯”大约是标准足球场的两个大，其重量估计有110亿磅。

Whereas DART is just a 1,260-pound spacecraft—about the size and weight of a dairy cow. 

而DART（航天器）只是一个1260磅的宇宙飞船——大约是一头奶牛的大小和重量。

The fact that DART made a dent at all really comes down to its high-velocity impact, which we already said was 14,000 miles per hour. 

DART砸出的坑实际上是由其高速撞击引起的，我们提到过，时速为每小时14000英里。

And all this took place after a deep-space voyage to the impact point, more than seven million miles from Earth.

此前，一次深空航行驶向距离地球700多万英里的撞击点。

So, that’s like a dairy cow smashing into a great pyramid?

这就像一头奶牛撞进了一个大金字塔中?

Basically, it gets messy.

基本上，一片狼藉。

Huh. Well, let’s get back to the science. 

嗯。好吧，让我们回归科学。

We know that getting more details is helping astronomers understand why this crash was so successful. 

我们知道，获得更多的细节可以帮助天文学家理解这次撞击如此成功的原因。

What are some of the new details around the impact that have been found? And what surprised scientists? What was NASA’s original goal here?

关于这次撞击，我们发现了哪些新的细节? 是什么令科学家们感到惊讶？美国宇航局最初的目标是什么?

That’s a great question Tulika. And the answer was that the surprise was how well it worked. 

这个问题问得好，图利卡。答案是，令人惊讶之处是撞击效果竟如此之好。

NASA’s official criterion for success was shifting Dimorphos’s orbit by just 73 seconds.

美国宇航局的官方成功标准是将“迪莫弗斯”的轨道改变73秒。

Initial predictions – if it was actually a billiard ball, for instance, all solid material – predictions were that maybe DART would nudge it off by about 7 minutes. Instead we got 33, 33 minutes!

假设“迪莫弗斯”是一个台球，那么它完全由固体物质组成，最初预测DART可能推动“迪莫弗斯”，使其快大约7分钟。实际上快了33分钟!

Yeah! And the difference is due to Dimorphos not being a billiard ball at all. 

对! 造成这种差异是因为“迪莫弗斯”根本不是一个台球。

It's a loosely bound rubble pile as DART's final closing images showed. 

正如DART的结束阶段图像所示，“迪莫弗斯”是由松散的碎石堆组成。

So when DART slammed into it, it ejected a huge plume, a long tail of debris, containing more than 2 million pounds of stuff, which imparted recoil, basically, to Didymos. It's a bit like a kick from a shotgun.

因此，当DART撞击“迪莫弗斯”时，它喷出了巨大的羽流，一长串碎石，包含了200多万磅的物质，这基本上赋予了“迪迪莫斯”后坐力。这有点与霰弹枪的后坐力相像。

Oh, wow. Well that really helps me visualize it a little bit more.

哦, 哇。这确实可以帮助我更直观地理解。

So DART was this $330 million spaceship the size of a golf cart — and it was completely obliterated by this asteroid in a matter of mere microseconds. 

DART是一艘价值3.3亿美元的宇宙飞船、体积有高尔夫球车大小，它在短短几微秒内就被这颗小行星完全摧毁了。

Scientists seemed pretty confident that this was a smashing success — but what else would we need in order to ensure that any more dangerous asteroids headed for earth don’t obliterate us? 

科学家们似乎很确信这是一次轰动性成功的尝试，不过，我们还需要了解什么才能确保任何撞向地球的更危险的小行星不会摧毁我们呢?

Great question, Tulika. What we really need to have is better situational awareness.

问得好，图利卡。我们真正需要的是更好的处境意识。

How many of these objects are out there? What are they made of? Where are they?

外太空还有多少这样的物体? 它们的组织结构是什么? 它们的位置在哪里?

And uh, who’s working on that now?

现在哪些人在研究这个?

Lots of different people.

很多不同的人。

The key is to get a catalog of different sizes of objects, their different orbits, maybe even what they're made of and figure out which ones are the most threatening.

关键是要了解一系列不同大小、处在不同轨道、甚至不同组织结构的天体，然后找出哪些天体是最具威胁性的。

So in terms of certain near term projects we've got Hera, is the first dimension. 

在一些近期项目中，我们发现了“赫拉”，这是第一个维度。

That's a project from the European Space Agency.

这是欧洲航天局的一个项目。

It's named after the Greek goddess who was married to Zeus, I believe, the queen of the gods.

这颗行星是以希腊女神的名字命名的，她是宙斯的妻子，是诸神之后。

The Queen, the Queen. 

王后，王后。

Now, Hera was originally supposed to arrive about the same time as DART at Dimorphos at Didymos. 

赫拉本该与DART航天器同一时间到达“迪莫弗斯”与“迪迪莫斯”。

But instead, due to delays, it is now not launching until late next year, it's going to arrive sometime in 2026. 

但是，由于延误，赫拉现在要到明年晚些时候才能发射，将于2026年某个时候到达目的地。

But that's still going to tell us a whole lot more about the aftermath of this epochal impact. 

但这仍将向我们展示更多关于这次划时代影响的后果。

Now, there are other things to mention as well. 

现在，还有其他要提的事情。

One project I'm excited about is NASA's NEO surveyor, the Near Earth Objects Surveyor Space Telescope. 

令我兴奋的一个项目是美国宇航局的NEO勘测器，即近地天体勘测空间望远镜。

That is an infrared space telescope that's meant to launch maybe sometime in 2028. 

这是一个计划在2028年某个时候发射的红外太空望远镜。

And it will be a very big step towards creating this catalog of objects, and getting a better sense of what's really out there and what the threats are. 

这将是创建天体目录、更好地识别外太空有什么天体以及存在什么威胁的重大一步。

And on the ground there’s something similar to the Vera C. Rubin Observatory. 

地面上的NEO勘测器类似于薇拉·鲁宾天文台。

One thing that's very important for this mission is it will be doing the same kind of work from the ground.

这项任务非常重要的一点是，NEO勘测器将在地面上完成同样的工作。

It will be taking these full, panoramic, high resolution images of the sky multiple times per night, each and every night making almost a high definition movie of the heavens above. 

NEO勘测器将在每晚拍摄数次完整的、全景式的、高分辨率的天空图像，每晚几乎都能拍摄出高清的太空图像。

And it'll be able to see little points of light moving around, some of which could be Earth threatening asteroids. 

NEO勘测器能捕捉到四处移动的小光点，其中一些可能是威胁地球的小行星。

Oh, and then that's named after Vera Rubin, right. 

那是以薇拉·鲁宾的名字命名的。

Indeed. One of the discoverers of dark matter, I believe, right? 

确实是。薇拉·鲁宾是暗物质的发现者之一，对吧?

Yes, yes. We also know that researchers with the help of amateur astronomers are continuing to comb through the DART data to find out more about the physics, geology and chemistry of these two asteroids.

是的。我们也知道，在业余天文学家的帮助下，为找出更多关于这两颗小行星的物理、地质和化学方面的信息，研究人员仍在持续梳理DART(航天器)的数据。

Lee, what are you looking forward to the most to finding out in the near future?

李，你最期待在不久的将来有什么发现?

Well, honestly, I kind of considered Didymos and Dimorphos a little done and dusted. 

说实话，我觉得“迪迪莫斯”和“迪莫弗斯”的工作彻底告一段落了。

We’ve already smacked the space rock, we've seen what's happened. 

我们已经成功撞击了太空岩石，观察到了相关情况。

I'm interested in getting this catalogue. I'm interested in knowing more about the properties of a wide diversity of asteroids, because it may not be a rubble pile that comes at us every time. 

我对这份星表很感兴趣。我对详细了解各种各样的小行星的特性很感兴趣，因为不是每次都有一堆碎石会向我们袭来。

What if it's a big ball of metal? What if it's made of ice? I don't know.

如果它是个巨大的金属球体呢? 如果它由冰组成呢? 我不知道。

That’s true. 

的确是这样。

So clearly, the answer is to just smack more cows into pyramids, to send out more of these sorts of missions and get a sense of what happens when we whack things really hard in the solar system.

很明显，答案就是把更多的牛撞进金字塔，发送更多这样的任务，了解当我们在太阳系中猛烈撞击天体时会是什么情况。

That said, I have to say, I don't think this is going to be enough to save us. 

尽管如此，我不得不说，我认为这不足以拯救我们。

There's a lot of situations where something could still hit us real hard and fast and DART definitely wouldn’t save us. 

仍会有很多天体又快又猛袭击我们的情况，而DART航天器绝对救不了我们。

I will definitely rest easy. 

我一定会高枕无忧。

I hope you do. 

我希望你可以。

Thanks for listening to Science, Quickly. I'm Tulika Bose.

感谢收听《科学快讯》。我是图利卡·博斯。

And I'm Lee Billings.

我是李·比林斯。

来源：Scientific American