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保护地球免受小行星撞击的方法

Methods for Protecting Earth against an Asteroid Strike

But space agency officials say even if such an asteroid keeps heading on a path toward Earth,

但航天局官员表示，即使这样的小行星继续朝着地球前进，

the world is now much better-equipped to defend itself against such a threat.

世界现在也有了更好的装备来抵御这种威胁。

The American space agency NASA recently estimated there was a 3.1 percent chance that asteroid 2024 YR4 would hit Earth on December 22, 2032.

美国航天机构NASA最近估计，小行星2024 YR4在2032年12月22日撞击地球的可能性为3.1%。

That is the highest probability predicted for such a large space rock in modern times.

这是在现代对如此巨大的太空岩石预测的最高概率。

Richard Moissl is head of the European Space Agency's (ESA) planetary defense office.

理查德·莫伊塞尔是欧洲航天局（ESA）行星防御办公室负责人。

While recognizing the risk the asteroid could present, he told the French news agency AFP people should not panic over such predictions.

尽管承认这颗小行星可能带来的风险，但他对法新社表示，人们不应该对这样的预测感到恐慌。

Astronomers have noted that the more data they gather, the odds of a direct asteroid hit are expected to keep rising over time.

天文学家注意到，他们收集的数据越多，小行星直接撞击地球的几率预计会随着时间的推移而不断上升。

However, scientists say at a certain point the odds will likely drop down to zero.

然而，科学家们表示，在某个时刻，这种可能性可能会降至零。

Moissl said he thinks it is important to remember that even in the unlikely event the probability keeps rising to 100 percent, the world is "not defenseless".

莫伊塞尔说，他认为重要的是要记住，即使这一不太可能发生事件的发生概率升至 100%，世界也“并非毫无防备”。

Here are some methods currently being considered as defensive measures to keep humanity safe in case there is a real threat.

以下是一些目前被认为是防御性措施的方法，以在出现真正威胁时保护人类安全。

Only one planetary defense method has been tried against an asteroid.

目前只有一种行星防御方法被尝试用来抵御小行星。

In 2022, NASA's Double Asteroid Redirection Test (DART) sent a spacecraft into the 160-meter-wide Dimorphos asteroid.

2022年，NASA的“双小行星重定向测试”（DART）发射一艘航天器撞击直径160米的迪莫弗斯小行星。

The effort successfully changed the asteroid's orbit around a larger space rock.

这一努力成功地改变了迪莫弗斯小行星绕更大太空岩石运行的轨道。

Bruce Betts is chief scientist for the nonprofit Planetary Society.

布鲁斯·贝茨是非营利组织“行星协会”的首席科学家。

He told AFP that space agencies could hit the 2024 YR4 asteroid with several spacecrafts, observing how each one changed the path.

他告诉法新社，航天机构可以用几艘航天器撞击2024年YR 4小行星，观察每艘航天器如何改变小行星路径。

The asteroid discovered in December is estimated to be 40-90 meters wide -- about half the size of Dimorphos.

去年12月发现的这颗小行星估计直径有40-90米宽，大约是迪莫弗斯的一半大小。

"You have to take care not to overdo it," Moissl warned.

“你必须小心不要过犹不及，”莫伊塞尔说警告说。

He said this is because if a spacecraft only partially destroys an asteroid, it could send smaller pieces of the space rock heading toward Earth.

他说这是因为如果航天器只部分摧毁小行星，那么这颗小行星可能会将较小的太空岩石碎片射向地球。

A separate idea would involve sending a large spacecraft to fly alongside a threatening asteroid.

另一个不同想法是发射一艘大型航天器与威胁地球的小行星并排飞行。

The spacecraft would not touch the asteroid, but would use its gravitational force to pull it away from Earth.

这艘航天器不会接触并排飞行小行星，但会利用其引力将小行星拉离地球。

Moissl said another non-contact plan would put a spacecraft near the asteroid to eject a continuous flow of atoms to push the asteroid off course.

莫伊塞尔说，另一个非接触式计划是发射一艘航天器到这颗小行星附近，以喷射出连续的原子流，将这颗小行星推离轨道。

Scientists have also considered painting one side of the asteroid white.

科学家们还考虑将这颗小行星的一侧漆成白色。

They believe this could increase the light the object reflects to make it slowly change course.

他们相信这可以增强物体反射的光线，使其缓慢改变方向。

One idea is to use a nuclear weapon against a threatening asteroid.

一个想法是使用核武器来对付具有威胁性的小行星。

In laboratory tests, researchers found that X-rays from a nuclear blast could move a rock.

在实验室测试中，研究人员发现核爆炸产生的X射线可以移动岩石。

But this is considered more of a plan for kilometers-wide asteroids like the one that killed off the dinosaurs.

但这更多地被认为是一种针对数千米宽的小行星的计划，就像杀死恐龙的小行星一样。

And this method also carries the risk that a nuclear explosion could send additional pieces of the asteroid falling toward Earth.

这种方法也有风险，核爆炸会使更多小行星碎片坠落地球。

A similar method -- but one considered less dangerous -- would involve shooting laser beams from a spacecraft to destroy the side of an asteroid in an effort to push it away from Earth.

一种类似的方法——但被认为不那么危险——将涉及从航天器发射激光束来摧毁小行星的一侧，试图将其推离地球。

Moissl said that if all else fails, at least the world will have a good idea where a threatening asteroid would strike.

莫伊塞尔说，如果所有这些方法都失败了，至少全世界也能清楚地知道一颗具有威胁性的小行星会撞击何处。

Since astronomers believe most asteroids would at most threaten to destroy one city,

由于天文学家认为大多数小行星最多只有摧毁一座城市的威胁，

efforts could be organized to get people out of an area before a strike.

因此可以组织起来，在小行星撞击前让人们离开一个地区。

"Seven-and-a-half years is a long time to prepare," Moissl added.

“还有七年半的时间做准备，这是很长的一段时间，”莫伊塞尔补充道。

He also noted that even with the rising odds involving 2024 YR4, there is still about a 97 percent chance the asteroid will miss Earth.

他还指出，即使2024 YR4与地球相撞的可能性越来越大，这颗小行星仍有约97%的可能性与地球擦肩而过。

I'm Jill Robbins.

吉尔·罗宾斯为您播报。