We live in a peaceful part of the Milky Way.

我們生活在銀河中較平和的部分

Our home is the Solar system,

我們的家就是太陽系

a 4.5-billion-year-old formation that races around the galactic centre at

現在45億歲的太陽系， 以每小時200,000公里的速度環繞銀河系中心

200,000 km/h and circles it once every 250 million years.

並在每2億5000萬年繞行銀河系一圈

Our star, the Sun, is at the centre of the Solar system.

我們的恆星太陽，是太陽系的中心

It’s orbited by eight planets,

它被八大行星環繞

trillions of asteroids and comets and a few dwarf planets.

還有上兆的小行星、彗星、矮行星

The eight planets. Divided into four planets like ours:

八大行星中的前四顆，類地行星： 水星、金星、地球、火星

Mercury, Venus, Earth and Mars,

八大行星中的前四顆，類地行星： 水星、金星、地球、火星

and four gas giants: Jupiter, Saturn, Uranus and Neptune.

以及後四顆，巨大的氣體行星： 木星、土星、天王星、海王星

Mercury is the smallest and lightest of all the planets.

水星是八大行星中最小最輕的

A Mercury year is shorter than the Mercury day, which leads to

在水星上的一年比一天還短，

enormous fluctuations in temperature.

對水星表面造成劇烈溫差

Mercury does not have an atmosphere or a moon.

水星沒有大氣層或衛星

Venus is one of the brightest objects in the Solar system and by far

金星是太陽系中最明亮的行星之一

the hottest planet, with atmospheric pressure that is

也是最炎熱的行星，金星上的大氣壓力比地球多了92倍

92 times higher than on Earth.

也是最炎熱的行星，金星上的大氣壓力比地球多了92倍

An out-of-control greenhouse effect means that Venus never

劇烈的溫室效應讓金星表面維持在437°C以上

cools below 437 °C.

劇烈的溫室效應讓金星表面維持在437°C以上

Venus also doesn’t have a moon.

同時，金星也沒有自己的衛星

Earth is our home and the only planet

地球，我們的家鄉

with temperatures that are moderate enough to allow for a surplus of liquid water.

也是太陽系中唯一溫度適中並能維持液態水的行星

Furthermore, it’s so far the only place where life is known to exist.

此外，地球也是目前唯一發現生物的星球

The Earth has one moon.

地球擁有一個衛星：月亮

Mars is the second smallest planet in the Solar system

火星是太陽系中第二小的行星

and hardly massive enough to keep a very thin atmosphere.

金星不大的質量讓他維持了一層非常薄的大氣層

Its Olympus Mons is the largest mountain in the Solar system,

這是奧林帕斯山，太陽系中最高大的山脈

more than three times as high as Mount Everest.

比喜馬拉雅山還高三倍有餘

Mars has two small moons.

火星擁有兩個小衛星

Jupiter is the largest and most massive planet in the Solar system.

木星是太陽系中最巨大、質量最重的行星

It consists largely of hydrogen and helium

它由大量氫及氦組成

and is the theatre for the largest and most powerful storms we know.

木星上也有人類觀測到威力及規模最巨大的風暴

Its largest storm, the Great Red Spot, is three times as large as Earth.

這是人類所知最巨大的風暴：大紅斑 它是地球的三倍大

Jupiter has sixty-seven moons.

木星擁有67個衛星

Saturn is the second largest planet and possesses the smallest density

土星是太陽系中第二大、密度最小的行星

of all the planets.

土星是太陽系中第二大、密度最小的行星

If you had a sufficiently large bathtub, Saturn would swim in it.

如果有一個裝得下土星的浴缸，木星會浮在水上

Saturn is also known for its extended, very visible ring system.

土星也以它的外環著名，一個非常明顯的土星環系統

It has sixty-two moons.

土星擁有62個衛星

Uranus is the third largest planet and one of the coldest.

天王星是第三巨大、第一冰冷的行星

Of all the gas giants, it’s also the smallest.

在所有類木行星中，它是最輕的

The special thing about Uranus is that its axis of rotation

天王星最特別的地方在於它的自轉軸

is tilted sideways in contrast to the seven other planets.

它的自轉軸斜向一邊，與另外七大行星都不同

It has twenty-seven moons.

天王星擁有27個衛星

Neptune is the last planet in the Solar system and is similar to Uranus.

海王星是太陽系中最靠外的行星，它與天王星類似

It’s so far removed from the Sun that a Neptune year is 164 Earth years long.

因為它距離太陽遙遠，海王星公轉太陽一圈需要164年

The highest wind speed ever measured was in a storm on Neptune,

人類目前觀測到的最高風速在海王星上的風暴

at just under 2,100 km/h.

風速僅略低 2,100公里/時

Neptune has fourteen moons.

海王星擁有14個衛星

If we compare the sizes of the planets,

若我們比較八大行星的尺寸

the differences between them become even clearer.

差異會看起來非常明顯

Jupiter is the leader in terms of size and weight;

木星擁有最大的尺寸及質量

small Mercury, on the other hand,

金星，甚至比木星的衛星：木衛三(Ganymed)還小

is even smaller than one of Jupiter’s moons, Ganymede.

金星，甚至比木星的衛星：木衛三(Ganymed)還小

Jupiter is so massive that alone it contains roughly 70% of the mass

木星擁有的質量占了八大行星總質量的70%

of all the other planets and has a massive impact on its surroundings.

木星擁有的質量占了八大行星總質量的70%

That’s a blessing for Earth, since Jupiter draws most of

木星的質量也為周遭環境帶來影響， 木星為地球擋下了許多危險的小行星

the dangerously large asteroids that could wipe out life on Earth.

木星的質量也為周遭環境帶來影響， 木星為地球擋下了許多危險的小行星

But even Jupiter is a dwarf in comparison to our star, the Sun.

但即使是木星，與恆星太陽相比仍是微不足道

Calling it massive does not do justice to the Sun.

它的質量在太陽面前非常渺小

It makes up 99.86% of the mass in our Solar system.

太陽占了整個太陽系99.86%的質量

For the most part, it consists of hydrogen and helium.

太陽大部分都由氫氣及氦氣組成

Only less than 2% is made up of heavy elements, like oxygen or iron.

只有2%是由較重的元素組成，例如氧及鐵

At its core, the Sun fuses 620 million tons of hydrogen each second

在太陽的核心中，每秒有6億2000萬噸的氫發生核聚變

and generates enough energy to satisfy mankind’s needs for years.

並年復一年地為人類產生能量

But not only the eight planets orbit our Sun.

但太陽系中環繞太陽的不只有八大行星

Trillions of asteroids and comets also circle it.

數以兆計的小行星、彗星也會環繞地球

Most of them are concentrated into two belts:

他們大部分都集中分布在太陽系中兩個區域

the asteroid belt between Mars and Jupiter

一個是位於火星及木星之間的小行星帶

and the Kuiper belt at the edge of the Solar system.

以及位於太陽系最外圍的古柏帶

These belts are home to countless objects, some as large as a dust particle,

這兩個行星帶有數不勝數的星體，小至粉塵

others the size of dwarf planets.

大至矮行星

The most well-known object in the asteroid belt is Ceres;

小行星帶中最知名的星體是穀神星

the most well-known objects in the Kuiper belt are Pluto, Makemake and Haumea.

古柏帶中最知名的星體是 冥王星、鳥神星、妊神星

Usually we describe the asteroid belt as

一般而言，我們將小行星帶描述成

a dense collection of bodies that constantly collide.

一個高度密集且常發生碰撞的區域

But in fact, the asteroids are distributed across an area that is

但事實上，小天體是分散在整個區域間

so indescribably large that it’s even difficult to see two asteroids at once.

所以與描述不同的是，兩個小天體不容易遇到彼此

Despite the billions of objects in them,

即使小行星帶中有幾十億個小天體

the asteroid belts are fairly empty places.

但其實這之間還是非常空曠的

And nonetheless, there are collisions over and over again.

但無庸置疑的，碰撞仍是會發生

The mass of both belts is also unimpressive:

小行星帶和古柏帶所帶的總質量也很微小

the asteroid belt has a little less than 4% of our Moon’s mass, and

小行星帶上的天體總質量少於月球的4%

the Kuiper belt is only between one 25th and one 10th of Earth’s mass.

古柏帶的總質量介於 1/25 ~ 1/10 個地球重

One day, the Solar system will cease to exist.

最終，太陽系將邁向終結

The Sun will die, and Mercury, Venus and maybe Earth too will be destroyed.

太陽將會死亡， 水星、金星將被摧毀，甚至連地球也可能遭殃

In 500 million years it will become hotter and hotter until at some point

再過5億年，太陽會變得越來越熱

it will melt Earth’s crust.

直到連地球的地殼都被融化

Then the Sun will grow and grow and either swallow Earth

接著太陽會膨脹地越來越巨大，最終吞噬地球

or at least turn it into a sea of lava.

或最少也會把地球變成岩漿海

When it has burnt up all its fuel and lost most of its mass,

當太陽失去它大部分的質量，將物質燃燒殆盡

it will shrink to a white dwarf and burn gently for a few billion more years

它會收縮成白矮星，並緩慢放熱數十億年

before it goes out entirely.

直到他完全熄滅

Then, at the latest, life in the Solar system will no longer be possible.

到那時候，要在太陽系中出現生物將不再可能

The Milky Way will not even notice it.

至於整個銀河甚至不會有人注意到這裡

A small part of it in one of its arms will become just a tiny bit darker.

對銀河而言， 只是其中一個旋臂上的小地方變得暗一點點

And mankind will cease to exist or leave the Solar system

至於人類將不復存在， 除非我們離開太陽系，出發尋找新的家鄉

in search of a new home.

至於人類將不復存在， 除非我們離開太陽系，出發尋找新的家鄉

Subtitles by the Amara.org community

字幕由GrayHS提供