(单词翻译:单击)
As many a late 90s film suggests, the Earth could be in a bit of trouble if a sufficiently-sized space rock were to slam into us.
正如很多上世纪90年代电影所讲的那样，如果太空里有一块大石块飞向地球，那么地球会遇到大麻烦。
And astronomers around the world are totally on top of it, monitoring potential threats and developing methods to avert a hypothetical Armageddon.
世界各地的天文学家都在努力避免这种情况发生：他们监测潜在的威胁，并研究各种方法来避免假想中的这一天。
Which is why last week, a sort of asteroid impact drill was conducted at the International Academy of Astronautics's annual Planetary Defense Conference,
于是，上周的时候，在国际宇航科学院的年度行星防御会议上，他们进行了一次小行星撞击影响的演练。
which demonstrated what might happen if an asteroid hit us within the decade.
这次演练表明了如果未来10年内真的有小行星撞击地球的话，可能会发生什么。
Over five days, the conference attendees played out what could happen after the discovery of a hazardous, but in this case totally fictional, asteroid.
在5天的时间里，与会者们演练了在发现一颗危险的小行星后会发生什么。不过演练过程是完全虚构的。
And it demonstrates some of the problems we might face if we had to tackle an asteroid threat for real.
这次演练展现了一些问题，这些问题是我们在现实中遇到真的小行星威胁后可能要解决的问题。
NASA's Jet Propulsion Lab created the initial scenario concerning a fictional asteroid dubbed 2019 PDC.
美国宇航局（NASA）喷气推进实验室（JPL）创设了初始情境，在这个情境里，有一颗虚构的小行星，名为2019 PDC。
In the real world, JPL's Sentry and the European Space Agency's CLOMON systems would calculate the chance of an impact, and refine those estimates over months of monitoring.
在现实世界中，JPL的哨兵系统（Sentry）以及欧洲太空总署（ESA）的CLOMON系统可以计算撞击的可能性大小，并通过数月的监测来不断精准估测结果。
But that can get tricky, sometimes an asteroid is too close to the Sun in the sky to observe, and other times its orbit takes it too far away, so it's too dim for our dedicated telescopes to pick up.
但这种方式比较难办，因为有时候小行星可能离太阳很近，有时候又可能很远，远到当前的任何望远镜都无法捕捉到。
According to the scenario, it was determined after one month of observation that 2019 PDC had a 1% chance of striking the Earth in 2027,
在这种情境下，在经过一个月的观测后，他们判定，2017年，2019 PDC有1%的可能性撞击地球。
and the asteroid was between 100 and 300 meters across.
这颗小行星在100-300米的大小之间。
A rock that size, with an impact chance of that magnitude, is listed as a 2 on the Torino Scale for impact hazards.
这样大小的石块，加上1%撞击的可能性，其冲击威胁的杜林危险指数是2。
Which is a scale that we have, by the way.
这个程度是在我们衡量范围内的。
But that's mostly because of the relatively low risk.
但这主要是因为风险相对较低。
A three hundred meter asteroid could ravage an entire continent if it actually hit the Earth in the right spot.
300米大小的小行星如果能以合适的角度撞击，是可以让整个地球毁灭的。
Hence the continued monitoring.
因此，天文学家还在进行持续的监测。
The second day of the conference corresponded to 4 months of theoretical observations, after which the risk of 2019 PDC's impact increased to 10%, and its size was narrowed down to between 140 to 260 meters.
会议的第二天正值理论观测4个月的时间。在那之后，2019 PDC撞击的威胁增加到了10%。而其大小也缩小到了140-260米之间。
Analysis of its orbit using computer simulations pinned down where it could possibly hit:
通过计算机模拟，并对其轨道进行分析，我们确定了它很有可能撞击地球的位置：
a 70 kilometer wide band stretching from Hawai'i to Africa.
从夏威夷到非洲之间长达70公里的宽带地区。
Yes, that is a big swatch of the planet. Including quite a bit of ocean.
这确实是地球上很大的一块地方了，其中还有很大一部分是海洋。
So, the Space Mission Planning Advisory Group, or SMPAG, a real-life group that monitors asteroid threats, made some recommendations.
于是，空间任务规划咨询小组（SMPAG）对小行星卫星进行了监测，他们给出了一些建议。
That included two different methods for knocking an asteroid off its current orbit that we could actually use:
其中还提供了2种不同的方法，可以用来让小行星偏转于当前的轨道之外。
a kinetic impactor, which would be a large spacecraft that rams into an asteroid really fast, or a nuclear detonation. Yes, nuke the asteroid.
这个方法是动力撞击器技术，即让一艘大型宇宙飞船以极快的速度撞击这颗小行星，即引发小行星的核爆炸。
If you detonate a nuclear bomb near an asteroid, some of its surface will vaporize, and it will recoil and hopefully get knocked off its collision course with Earth.
如果在某颗小行星附近引燃核炸弹，其部分表面会蒸发并萎缩，然后就有可能偏离于会与地球发生撞击的轨道之外。
Either way, we'd have to get working pretty soon.
无论是哪种情况，我们都要尽快着手了。
Because we'd have to change the asteroid's orbit before 2025
因为我们必须在2025年之前改变这颗小行星的轨道。
for the relatively small deflection caused by the blast to actually make 2019 PDC miss the Earth.
通过爆炸引发的细微偏离让2019 PDC与地球完美错过。
And it'll take one to two years for a craft to actually get there.
太空飞船需要1-2年时间才能抵达那里。
On top of that, just like our missions to other distant space bodies, you really only get one launch window a year, if not fewer.
更重要的是：跟其他去往遥远天空星体的任务一样，这次任务也只有最多1年的启动时间。
So basically, we'd only have a couple of years to get the plan figured out.
所以，总体来说，我们只有几年时间来部署计划。
But one problem that would very likely come up in the real world, and did in the fictional scenario,
但有一个问题可能不仅存在于科幻世界，也会发生在现实生活中，
is that we don't have enough data on the asteroid to know exactly how much we need to deflect it,
那就是：关于这颗小行星，我们没有足够的数据，所以无法精确得知需要偏转多大的程度才能避免灾难，
and therefore what exactly we need to hit it with.
因此，我们自然也就不知道需要用什么来撞击这颗小行星。
Rather than just sit and wait over a year for it to get close enough to observe again, we could send a reconnaissance probe to it.
我们不会坐以待毙等1年的时间，虽然1年后，观测的距离会足够近。相反，我们会发送一个侦查探测器去往这颗小行星。
But that would take precious time, and it would leave not much wiggle room to analyze that data and then launch the deflector.
但这个过程会耗费许多宝贵的时间，也没有留下太多可回旋的空间让我们来分析这个数据，以及后续启动偏针仪。
It's conference day three now, and we did decide to send a recon craft.
会议进行到第三天的时候，我们终于决定发射一颗侦查探测器。
It arrived just before new year's of 2022, and the extra data from it told us that 2019 PDC is going to hit Denver.
这颗探测器会在2020年新年之前抵达，而它发回的精确数据也让我们得知：2019 PDC将在丹佛市发生撞击。
We were also able to learn more about the rock's makeup.
我们也能对这块大石头的组成有更多了解。
It appears to be a giant rubble pile, 140 to 220 meters in size.
它看起来像是一个大型的碎石堆，大小在140-220米之间。
Based on that, the asteroid would explode 6 to 9 kilometers above the Earth's surface, creating a blast one hundred times the size of the Tunguska impact back in 1908.
基于这些数据，这颗小行星会在地球表面上空6-9千米的地方发生爆炸，其爆炸影响范围是1908年通古斯大爆炸的100倍。
That space rock leveled 2000 square kilometers of uninhabited forest, 80 million trees, and shattered windows in villages up to 60 kilometers away.
其撞击会将2000平方千米的无人森林夷为平地，会波及8000万棵树，震碎60公里开外的村庄的窗户。
Only one human reportedly died, but many a reindeer got crispied-up.
据报道，只有1人死亡，不过有很多驯鹿丧生。
To prevent this far worse hypothetical disaster, NASA, the ESA, and the Japanese, Russian, and Chinese space agencies planned to launch six separate kinetic impactor crafts.
为了避免这场假想中的灾难愈演愈烈，美国、欧洲、日本、俄罗斯、中国的空间机构计划发射6个单独的动力撞击器。
They'd launch in mid 2023.
他们会在2023年中旬发射。
Based on estimates of the asteroid's mass, it should only take three such impactors to nudge it off course.
根据对这颗小行星质量的估测，大概只需要3个撞击器就能让这颗小行星偏离轨道。
The others would be backups. Which seems smart, since we're talking about losing Denver.
另外3个是替补，这招看起来很机智，毕竟丹佛是很重要的城市。
But as a separate backup, NASA could send another recon probe carrying a nuclear device.
不过，还有另一个单独的替代方案：NASA会派另一个侦查探测器，上面会配有核装置。
There is one problem with that plan, which is that launching a nuke into space is a violation of international agreements.
不过，这个计划有个问题：将核装置送往太空是违背国际公约的。
So we'll have to navigate that political problem if it ever comes to it.
所以我们只有等走到那一步的时候再来看看这个政治问题如何解决了。
But in this scenario, they actually decided against using a nuke.
不过，在这种情境下，他们大概还是会决定不使用核装置。
Day 4 of the conference corresponds to September 2024.
会议的第4天模拟的是2024年9月。
Denver's safe; the kinetic impactors worked, but chipped off a 50 to 80 meter chunk of the asteroid, and that bit is still headed to Earth.
丹佛市安全了，动力撞击器奏效了，不过也让这颗小行星失去了50-80米的部分，而这部分还在向地球进发。
Perhaps luckily, it's got about a 50% chance of hitting the Atlantic.
或许，如果足够幸运的话，这部分有50%的可能性撞击大西洋。
Unfortunately, observations are on hold for a few months because the rock is behind the Sun.
如果不幸的话，观测要暂停几个月，因为这个石块在太阳后面。
Nukes came back into the discussion, with the SMPAG suggesting we use one to break up the fragment into even smaller pieces,
利用核力量来解决问题又再次成了讨论的主题，而SMPAG也建议我们使用核武器来避免这部分石块分崩离析。
most of which would hopefully burn up in the atmosphere.
因为它们分崩离析后会在大气层发生灼烧。
On the last day of the conference, corresponding to ten days from impact,
会议的最后一天对应着撞击发生的10天后。
it was announced that a 60 meter fragment will explode 13 to 15 kilometers over Central Park in New York City.
会议当天宣布，有一个60米大小的石块会在纽约市中央公园上空13-15公里的地方发生爆炸。
One thousand Hiroshima bombs worth of energy, inflicting serious damage within 33 kilometers.
其爆炸所释放的能量会是广岛爆炸的1000倍，会在33公里内造成严重的损害。
And none of the attempts in the intervening years had managed to stop it.
任何干预手段都无法阻止这种损害。
Since it's hitting one of the largest cities on the planet, over ten million people would need to be evacuated.
因为它撞击的是地球上最大的城市之一。届时将有1000多万人需要疏散。
And the impact would render the city unlivable, leaving millions without homes even if they survived.
这次冲击将导致该市无法居住，让上百万人无家可归，就算这些能幸存。
The estimated damage exceeded $70 billion in the local New York and New Jersey area, which could expand to a loss of over $2 trillion worldwide.
据估测，纽约当地和新泽西地区的损害将超过700亿美元，全球范围内的损失将超过2万亿美元。
Which was a pretty grim end to the scenario, although they were able to theoretically prevent an even worse disaster.
如果那一天到来，会真的挺惨烈的，虽然科学家理论上能阻止灾害更加恶化。
Lucky for us here in actual 2019, there are not any asteroids we've detected that have even a 1% chance of hitting us in the next several centuries.
对于生活在2019年的我们来说，还没有什么小行星会在未来几百年里有1%的可能性与地球相撞。
As such, no object has above a zero on the Torino scale, and we've got plenty of time to develop our anti-impact plans.
也就是说，目前还没有什么物体对我们的杜林危险指数大于零，所以我们有充足的时间来研讨抗撞击计划。
I mean we have been hit by some pretty nasty space rocks in the past, so it is bound to happen one day.
而且地球以前也受到过宇宙石块的撞击，所以以后也有可能发生。
Just probably not when any of us are alive to see it.
不过，我们在座的各位有生之年不一定能看到了。
Thanks for watching this episode of SciShow Space News.
感谢收看本期的《太空科学秀》。
If you can't get enough of science-y goodness, reminder that we also have a podcast and it's very good! I love it.
如果大家还没看够，在此温馨提示我们在播客上也有很棒的节目。我本人很喜欢。
SciShow Tangents is a collaboration between Complexly and WNYC studios.
SciShow Tangents播客频道由Complexly和WNYC电台联合主办。
It's hosted by me, and a bunch of other awesome people who work for SciShow including:
我是这个频道的主持人，此外还有很多很棒的人，包括但不限于：
SciShow co-host and producer Stefan Chin, SciShow producer Sam Schultz (he is standing behind the camera right now), and Crash Course editor Ceri Riley.
《太空科学秀》的搭档主持、制片人斯蒂芬·钦，《太空科学秀》制片人萨姆·舒尔茨（他现在正在镜头后面看着我），以及《速成课》编辑切里·赖利。
Which is… It's just a great group humans! They're really smart and funny.
总之，这是一个无比优秀的团队。大家聪明又幽默。
Every episode, we get together and try to blow each other's minds with amazing science facts, and try not to go on tangents, and totally fail at that.
每一期节目，我们都会一起通过让人惊艳的科学事实来给听众惊喜，尽量不用高深的科学术语来让大家困惑。
We also play Truth or Fail, where we try to stump each other with two made-up facts and one real one. And there's poetry. There's poetry!
我们还会玩儿Truth or Fail的游戏，即用2个编造的事实和一个真实的事实来难倒彼此。此外还有与诗歌有关的环节哦！
Join us every Tuesday for episodes wherever podcasts are downloaded.
敬请关注每周二播客的更新哦!
And thank you for listening!
感谢收听我们的节目！
