that we may never be able to answer,

可能永遠無法解答

like is time travel possible?

像時間旅行有可能嗎？

Or are aliens living somewhere else in the Milky Way?

或銀河系裡有外星人嗎？

But there is one thing I believe about space:

但我相信一件關於太空的事：

Space is trying to kill me.

太空想殺我

Space isn't out to get me personally.

它不只想殺我

It's also trying to kill you and everybody else.

也想殺你和每個人

Think about it.

想想看

Space doesn't naturally have what we need to survive

太空不會自然供應生存必需品

when we travel there:

讓我們進行太空旅行

no air,

沒有空氣、

it's too hot

有時太熱、

or too cold,

有時太冷、

no ozone to protect us from those nasty UV rays, either.

沒有臭氧層可阻擋惱人的紫外線

This all sounds bad,

這一切聽起來都很糟

but what can space really do to me

但太空能對我怎樣

if I stay on Earth?

如果我待在地球上呢？

What we need to understand is that objects in space

我們要知道，太空中的物體

can cause people to think their days are numbered,

會讓人覺得日子已屈指可數

even when there are events on Earth

即使地球還有許多事

that can hurt or kill us

在太空動手前

before something from space does.

早就能讓我受傷或死亡

So, what are the odds that one of these objects

所以，太空物體有多少機率

will really affect Earth

會真的影響地球、

and you

你、

and me

我、

in our lifetime?

在我們一生中？

Well, we can take what we know about the universe

我們可以用對宇宙的了解

to try and figure that out.

試著找出答案

You might have heard stories

你也許聽過許多

about asteroids hitting the Earth.

小行星撞擊地球的故事

That would be pretty bad.

那一定很糟

Scientists think asteroids might have killed off

科學家認為小行星可能造成了

most of the dinosaurs.

大多數恐龍的滅絕

Sounds like something we should worry about, right?

聽起來我們該要擔心，對吧？

Well, astronomers can now watch asteroids in space

天文學家已能觀察太空中的小行星

and see them coming using complex computer models

然後用複雜的電腦模型

to predict the deadly rock's path.

預測致命岩石的路徑

For a while, the reported odds

有一陣子，預測

that asteroid Apophis would strike Earth in 2036

小行星阿波菲斯 (Apophis) 2036 年撞擊地球的機率

were once 1 in 625.

是 1/625

But, after updating their data,

但更新數據後

astronomers now say the chances are extremely low.

天文學家現在認為，可能性極低

Okay, what about the sun?

好吧，那太陽呢？

Hollywood movies like to pick on our sun

好萊塢電影喜歡在太陽上作文章

by showing Earth destroyed by solar flares

上演太陽閃焰毀滅地球

or the sun dying out,

或是太陽燃燒殆盡

which would cause Earth to freeze.

導致地球冰凍

Astronomers predict our sun contains enough gas

天文學家預測太陽有足夠的燃料

to make energy for another 3 to 5 billion years.

再提供三十到五十億年能量

So, in 3 to 5 billion years,

所以，在三十到五十億年後

if people still exist on Earth,

如果地球上還有人

they'll have to deal with that.

他們就要面對這個問題

But today, well, we're safe.

但目前我們很安全

Sometimes the sun does shoot flares at Earth,

有時太陽的確會朝地球發出閃焰

but the magnetic fields surrounding our planet

但環繞地球的磁場

blocks most of that radiation.

擋住了大部份的輻射

The radiation that does get through

真正通過的輻射

creates things like the Aurora Borealis.

造成了極光之類的現象

Gigantic solar flares can mess with our satellites

巨型的太陽閃焰會干擾人造衛星

and electrical equipment,

還有電子儀器

but the chances of it killing you are pretty slim.

但殺了你的機會微乎其微

Okay, what about that supermassive black hole

好吧，超大質量黑洞不就在

in the middle of our galaxy?

我們銀河系的中心嗎？

What happens to Earth,

地球和我們

and us,

會怎麼樣

when it pulls us in?

如果被吸進去呢？

After all, it is supermassive.

畢竟它是超級黑洞

Nope, not going to happen.

不，這不會發生

That's one big object that can't bother us.

這個大傢伙沒辦法影響我們

How can we be so sure?

我們為什麼這麼確定？

Our solar system is on the edge of the Milky Way

我們的太陽系，在銀河系的邊緣

while the nearest supermassive black hole

而最接近的超大質量黑洞

is about 26,000 light years from Earth.

離地球將近兩萬六千光年

That means we aren't on that black hole's menu.

這表示我們不在黑洞的菜單上

So, you still think space objects are trying to kill you

你還是認為太空想殺了你嗎，

even after what I've told you so far?

即使我說了這麼多？

I think I've even convinced myself

我覺得我幾乎已經說服自己

that odds are really good

機率相當低

that space and the objects up there

太空、還有太空中的物體

won't kill me after all.

終究不會殺了我

But I'll probably keep looking up

但我可能還是會持續看著天空

just to make sure nothing is headed my way.

只是想確定沒有東西朝我飛來