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Why people stillworry about the falling Chinese space station — despite the low odds

为什么人们仍然担心坠落的中国空间站——尽管可能性很小



In 2016, Chinaannounced that its first human station, Tiangong-1, would make an uncontrolledreentry into Earth’s atmosphere, and given the module’s large size and density,some big pieces might survive all the way to the ground. It’s predictablygarnered a lot of attention, and the panic just won’t go away.
Of course, therehave been the standard frantic articles about the “doomed” station “spiralingout of control.” Some stories have insinuated that the station will fall in NewZealand’s backyard — though it’s far too early to know where it’s going toreenter. Others have hyped up the idea that toxic debris will rain down onEarth. It’s all hogwash.

2016年,中国宣布它的第一个载人空间站“天宫一号”将失控重新进入地球大气层,考虑到这个组件的体积和密度,一些大的碎片可能会一直存留直到地面。它不出所料的引起了很多关注,而恐慌也不会消失。
当然,有一些关于“注定要失败”的空间站“急遽失控”的慌乱文章。一些故事含沙射影的暗示,空间站将坠落在新西兰的后院--尽管现在还太早难以得知它会回落到哪里。另一些则大肆宣扬有毒的碎片会洒落地球上。这都是废话。

As a spacereporter, I find this frustrating because I know how often objects fall toEarth without us being able to control them. The truth is Tiangong-1 is thelast thing anyone needs to worry about. Yes, the module is a bit bigger thanmost satellites that fall back to Earth, but the odds of any pieces falling onyour head are minuscule — less than your chances of getting hit by lightning.In fact, you can read all the reasons why you shouldn’t be scared of the spacestation in our article. A lot of other reporters have done some great reportingon this topic, too. But despite all of the information that’s available, I’ve runinto an interesting problem: people are still scared when I tell them the odds.
It’s somethingthat’s baffled me. Multiple people have asked about this, and even after Iexplain the situation, they still seem uneasy. Earlier this year, for instance,my co-worker Russell Brandom sent me an article about Tiangong-1’s demise. Ipointed him to our article, and told him everything was going to be fine. Hispanic didn’t subside. “Even a small chance of being killed by space debrisseems like too much,” he told me.

作为一名太空记者,我觉得这很令人沮丧,因为我知道如果没有我们的控制,目标就会经常坠落到地球上。事实上,天宫一号是人们最不需要担心的事情。是的,这个组件比大多数卫星返回地球时要大一点,但是任何碎片落在你头上的几率极小——比你被闪电击中的几率要小。事实上,你可以阅读我们文章中不应该害怕空间站的所有理由。许多其他记者也对这个话题做了一些很棒的报道。但是,尽管有这些信息,我还是遇到了一个有趣的问题:当我告诉人们这个几率的时候,人们还是很害怕。
这让我很困惑。很多人都问过这个问题,甚至在我解释了这个情况之后,他们似乎仍然感到不安。例如,今年早些时候,我的同事拉塞尔·布兰登给我发了一篇关于天宫一号终结的文章。我指给他看我们的文章,告诉他一切都会好起来的。他的恐慌并没有平息。他告诉我:“即使是被太空碎片杀死的可能性也很小,但那些碎片看起来太多了。”

Russelltechnically has a small chance of being hit by space debris all the time —well, an infinitesimal one. A person’s lifetime risk of being hit by reenteringspace debris is about one in a trillion, according to the AerospaceCorporation, a nonprofit research organization that provides guidance on spacemissions. Tiangong-1 isn’t going to drastically increase those odds.

从技术上来说,拉塞尔有很小的几率被空间碎片击中——嗯,一个无穷小的概率。一个为太空任务提供指导的非营利性研究机构——航空航天公司的数据显示,一个人一生中被再进入的太空碎片击中的风险大约是万亿分之一。天宫一号不会大幅增加这个几率。

So why is thespace station still scaring people? I think most of the problem began with thefirst reports in 2016 that Tiangong-1 was “out of control.” It’s true: Chinadoesn’t have the ability to maneuver the space station from Earth anymore, andits orbit is slowly decaying. But this idea of an uncontrollable space stationprobably inspired visions of a huge chunk of metal spiraling wildly towardEarth. Plus, US companies nowadays often come up with ways to safely de-orbitlarger pieces of metal they send to orbit. “There are a lot more controlledreentries than 20 years ago, and for more massive objects, [companies and countries]take more care,” says Jonathan McDowell, an astrophysicist at Harvard andspaceflight expert.

那么为什么空间站还是让人们感到害怕?我认为,大部分问题始于2016年的第一次报道——天宫一号“失控”。 这是真的:中国再也没有能力从地球上操纵空间站了,它的轨道正在慢慢变低。但是,这种无法控制的空间站的想法可能激发了一大堆金属在疯狂地向地球洒落的景象。此外,美国公司现在经常会想出办法,安全地将他们送入轨道的大块金属碎片脱离轨道。哈佛大学的天体物理学家、航天专家乔纳森·麦克道尔说:“与20年前相比,有更多的受控制的重返,对于更大规模的物体,[公司和国家]要更加小心。”

Still,uncontrolled reentries happen all the time. The upper stages of SpaceX’s Falcon9, Russia’s Soyuz, or Europe’s Ariane 5 rockets don’t always do a controlledde-orbit after every launch. Those pieces range from two to four tons, sothey’re not quite as massive as Tiangong-1. But a rocket piece about the samemass as the Chinese space station made an uncontrolled fall to Earth this year.The upper stage of a Russian Zenit rocket fell over Peru in January, and it’sabout eight tons, close to the size of Tiangong-1. A tank or two made it to theground, but no injuries were reported.

然而,不受控制的再进入时有发生。SpaceX公司的猎鹰9号、俄罗斯的联盟号或欧洲的Ariane 5号火箭的上一级火箭在每次发射后并不总是都能进行控制。这些碎片的范围从2吨到4吨不等,所以它们不像天宫一号那么大。但是,一枚与中国太空站相同质量的火箭,今年却失控坠落。今年1月,俄罗斯一枚泽尼特火箭的上一级在秘鲁上空坠落,大约有8吨,接近天宫一号的大小。一或两个仓到达地面,但没有人员伤亡报告。



Granted, the Zenitupper stage is mostly comprised of empty fuel tanks, and Tiangong-1 is denser.“It’s got a lot of heavy equipment, so it’s not like a rocket stage that’s abig empty tank,” says McDowell. “People are worried more [about if] it mightreach the ground.” That may be the other piece of the puzzle, too: the idea ofa space station falling to Earth is more menacing than a piece of a rocket oran average satellite.

当然,泽尼特的上一级主要由空燃料箱组成,而天宫一号则更密集。麦克道尔说:“它有很多重型设备,所以它不像火箭的部分是一个巨大的空罐。”人们更担心的是它是否会落到地面。这也可能是另一个难题:空间站坠落到地球的想法比火箭或普通卫星的坠落更具有威胁性。

I’ve started towonder if this isn’t just another example of how our brains aren’t very good atassessing real-world risks. Our brains are very sensitive to risk. That’s whatkept us alive back when everything around us was a legitimate risk toourselves. This backfires today because we hear about all sorts of things thatseem dangerous but aren’t likely to harm us at all.

我开始怀疑这是不是我们大脑不擅长评估现实世界风险的又一个例子。我们的大脑对危险非常敏感。当我们周围的一切对我们自己是一个合理的风险时,就是这些让我们活着。这在今天去相反,因为我们听到了各种看似危险但不太可能伤害我们的事情。

Novelty definitelyplays a role. This is the same reason many people are far more worried aboutplane crashes (which aren’t common anymore) than car crashes (which happen allthe time). Plane crashes seem rare and terrible, and so they stick in our mindsmore; car crashes, while tragic, don’t grab our attention. It’s easy to feelfrightened by terrorist attacks, which seem catastrophic, but we’re actuallymore likely to be killed by falling furniture.

新奇的事物无疑起着一定的作用。这也是为什么许多人更担心飞机失事(这已经不常见了),而不是担心车祸(这种情况经常发生)。飞机失事似乎很少见,也很可怕,所以它们更能留在我们的脑海里;而车祸虽然很悲惨,但并没有引起我们的注意。人们很容易对恐怖袭击感到恐惧,这似乎是灾难性的,但实际上,我们更有可能被掉落的家具砸死。

The Nobel Prize-winningpsychologist Daniel Kahneman is famous for suggesting that our brain runs twosystems: System 1 and System 2. System 1 is your quick, intuitive, emotionalresponses, like being afraid when you hear that a space station could fall onyour head. System 2 is the deliberate, reasonable response that takes a lot ofcognitive energy, like slowing down to calculate the probability that the spacestation will actually fall on your head. You can’t stop System 1 from running,and emotions are powerful. Unfortunately, not a lot of people take the time todo the calculations, and so they remain afraid.

诺贝尔奖得主、心理学家丹尼尔·卡尼曼因提示我们的大脑运行着两个系统而闻名:系统1和系统2。系统1是你快速、直观、情绪化的反应,比如当你听到空间站可能掉到你头上时的恐惧。系统2是经过深思熟虑的,理性的反应,需要大量的认知能量,比如缓慢的计算空间站会落到你头上的概率。你无法停止系统1运行,情绪是强大的。不幸的是,没有多少人花时间去计算,所以他们仍然害怕。

So, Russell’s fearof even a small chance of space debris falling on him is a great example ofSystem 1 out of control. I told him this. “Are fears ever rational?” he asked.“I feel like you’re just afraid of the things you’re afraid of.” It’s a goodpoint. Every time I pass over the Queensboro Bridge in New York, I think aboutour car swerving and plunging into the East River. It’s not likely to happen,but I’ll forever worry about it even if someone tells me the odds.

所以,拉塞尔对哪怕是很小的空间碎片坠落的恐惧都是系统1失控的一个很好的例子。我告诉他这一点。“恐惧是理性的吗?”他问道。“我觉得你只是在害怕你所害怕的东西。”这是一个很好的观点。每当我经过纽约的昆斯伯勒大桥,我就会想我们的车突然转向然后窜入东河里。这是不可能发生的,但即使有人告诉我几率很低,我也永远会担心。

The good newsabout Tiangong-1 is that people won’t have to worry for much longer. TheEuropean Space Agency estimates that the station will likely come down sometimebetween March 29th and April 9th, though those dates are still subject tochange. Once it falls, the risk will be eliminated. But if you want to scareyourself with space debris, there’s always NASA’s Hubble Space Telescope:unless NASA sends another mission to Hubble, the observatory will have to comedown at some point, too — and it’s even heavier than Tiangong-1.

关于天宫一号的好消息是,人们不用担心太长时间了。欧洲航天局估计空间站可能会在3月29日到4月9日之间的某个时候降落,尽管这些日期仍有可能发生变化。一旦它坠落,风险就被消除了。但如果你想用太空碎片来吓你自己,还有NASA的哈勃太空望远镜:除非NASA向哈勃发送另一项任务,否则望远镜也会在某一时刻落下来——它甚至比天宫一号还要重。