Name: 小行星為何不是行星的真正原因！ (The REAL Reason Asteroids Aren't Planets)
Uploaded: 2026-01-23T18:27:37.000Z
Duration: 4 min 23 s

When the first asteroids were discovered over 200 years ago.

在兩百多年前，第一批小行星被發現的時候

大家還把牠們當成是新的行星呢

And the story goes that the rapid and overwhelming discovery of hundreds.

故事是這樣發展的，因為發現了好多好多

Quickly convinced scientists that asteroids shouldn't be planets.

讓科學家們很快就相信，小行星不應該算是行星

The real reason asteroids were demoted from planet status.

小行星被降級，不再被視為行星的原因

Came nearly a hundred years after the hundredth asteroid was discovered.

是在第一百顆小行星被發現將近一百年後才出現

而在第一千顆小行星發現後的幾十年

And had nothing to do with their quantity, but in fact, their quality.

這跟牠們的數量一點關係都沒有，而是跟牠們的「品質」有關

Of course, up until 1800, only seven primary planets.

當然，直到1800年，只有七顆主要行星。

Only seven primary planets had been Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Uranus.

僅有的七顆主要行星是水星、金星、地球、火星、木星、土星和天王星。

But telescopes got better, and we found more.

但望遠鏡越來越好，我們發現了更多。

A small eighth primary planet, Ceres, was discovered in 1801 between Jupiter and Mars.

在1801年，木星和火星之間發現了一顆名為穀神星的小型第八顆主要行星。

And then there was a surge of new planets.

Discovered with almost identical orbits to Ceres, Pallas, Juno, Vesta.

發現了軌道與穀神星幾乎相同的衛星、智神星、婚神星、灶神星。

And more and more and more, it soon became clear that there was a band of small planets.

越來越多，很快就發現有一群小行星。

Orbiting the sun between Mars and Jupiter.

在火星和木星之間繞太陽運行。

And so, when describing the solar system, Astronomers found it useful to group them together as the small planets, the minor planets, the planetoids, the asteroids, or the numbered planets.

是以，在描述太陽系時，天文學家發現將它們歸類為小行星、矮行星、小行星、小行星，或編號行星很有用。

Because eventually, so many were being discovered so quickly.

因為最後發現的實在太多了，而且速度非常快。

It was easier to keep track of them all with numbers.

But there wasn't yet any scientific reason to stop thinking of the asteroids as planets.

但當時並沒有什麼科學上的理由，讓我們不把這些小行星當成行星。

I mean, having too many isn't by itself a good scientific criteria.

也就是說，數量太多本身並不是一個好的科學標準。

Think of all the thousands of known planets we've now discovered orbiting other stars.

想想看，我們現在已經發現了數千顆繞著其他恆星運行的行星。

Their sheer number isn't a reason not to call them planets or the elements.

他們的數量眾多，並不是不把他們稱為行星或元素的理由。

只是因為我們發現了更多元素。

Doesn't mean we should stop calling them elements.

並不代表我們就不該稱它們為元素。

So despite some embarrassment over the rapidly growing list of planets.

所以，儘管快速增加的行星列表讓人有點尷尬。

19th and early 20th century astronomers still considered all the asteroids to be planets.

19世紀和20世紀初的天文學家們，仍然將所有的小行星都視為行星。

Well, except one astronomer who argued that the asteroids should be their own category.

嗯，除了有一位天文學家主張小行星應該自成一類。

But his reasoning was based on incorrect data and theoretical misunderstandings.

但他的理由是基於錯誤的數據和理論上的誤解。

And was ultimately rejected by the wider astronomical community.

而且最終被更廣泛的天文學界所駁斥。

Even today, the International Astronomical Union's commission on asteroids.

即使在今天，國際天文學聯合會的小行星委員會。

Is still technically named the Minor Planet Center.

技術上仍然叫做「小行星中心」。

Even though, as we're about to discover, it's a poor name for them.

儘管，正如我們即將發現的，這個名字對它們來說不太恰當。

So why don't we include the asteroids in our list of planets today?

那麼，為什麼我們今天不把小行星納入我們的行星列表呢？

Look at this analysis of scientific papers in the last 200 years.

看看這份過去200年科學論文的分析。

The terms small planet and minor planet had consistent use relative to asteroid.

「小行星」和「矮行星」這兩個詞相對於「小行星」的使用是一致的。

Right up until 1953, when, boom, their use plummeted.

一直到1953年，突然間，它們的使用量就急劇下降。

This change wasn't because of a fear of a huge list of planets.

這個改變不是因為害怕行星列表會變得太長。

Asteroids, it turns out, Are not just miniature versions of the larger planets, but

原來，小行星不只是較大行星的縮小版，

are in fact, fragments from the collisions and disintegration of other planets.

事實上，它們是其他行星碰撞和解體後產生的碎片。

This distinction matters because when planets form, the release of gravitational potential energy Partially melts their interiors, Causing heavy elements to sink to the core and lighter materials to float upwards, Sorting into layers.

這個區別很重要，因為行星形成時，重力位能的釋放會部分熔化它們的內部，導致重元素下沉到核心，而較輕的物質則浮上來，分層排列。

If asteroids were formed like planets, but

如果小行星像行星一樣形成，只是

smaller, they would each be made of a mix of materials and would be too small to have enough energy to sort the materials into layers.

體積較小，它們各自會由混合材料組成，並且能量不足以將材料分層。

If instead, asteroids were relics from collisions between planets, each one would be a mostly homogenous chunk of material From a single layer.

相反地，如果小行星是行星碰撞後的殘骸，那麼每一個都會是來自單一層、大致均質的材料塊。

And what astronomers figured out Was that asteroids Are definitely broken planet pieces.

而天文學家們發現，小行星確實是行星破碎後的殘骸。

In fact, asteroids are literally classified into groups Based on what materials they're made of.

事實上，小行星的分類是根據它們的組成材料來決定的。

Out of the ridiculous number of objects in the asteroid belt, There are only three or four that we think formed on their own as a planet.

在小行星帶數量龐大的天體中，只有三四顆我們認為是獨立形成的行星。

Rather than being broken fragments, these three or four are the Ceres, Vesta, Pallas, and maybe Hygiea.

這三四顆不是破碎的殘骸，而是穀神星、灶神星、智神星，或許還有 гигиея。

So the asteroids were demoted to non planet status, not by a vote, Nor from a fear of long lists of planets, Due to a scientific discovery that asteroids are, in fact, Physically different From everything else that we call planets.

所以小行星被降級為非行星，不是因為投票，也不是因為怕行星列表太長，而是因為科學發現，小行星在物理上與我們稱為行星的其他天體完全不同。

The discovery meant they were split off in the minds of scientists into their own group, and

這項發現意味著科學家們在概念上將它們劃分到一個獨立的群體，

those scientists organically Stopped calling them planets.

科學家們自然而然地不再稱它們為行星。

In principle, the taxonomic split could have gone the other way.

原則上，分類上的劃分也可以是反過來的。

Researchers could have kept calling asteroids planets and come up with a new name for the remaining non fragmented objects like the earth.

研究人員可以繼續稱小行星為行星，然後為像地球這樣未破碎的物體另外取名。

But given the fact that asteroids were already previously considered A subcategory of planet minor planets, it makes much more taxonomic sense to split them off and keep all the rest of the planets as planets.

但考量到小行星先前已被視為行星的子類別「矮行星」，將它們分開並將其餘天體保留為行星，在分類上更有意義。

By this logic, we should probably also stop calling Ceres, Vesta, and

照這個邏輯，我們或許也該停止稱穀神星、灶神星和

Pallas astero since they formed like planets do.

帕拉斯為小行星，因為它們的形成方式和行星一樣。

So even though there are lots of asteroids.

For the question of whether or not asteroids count as planets, it turns out that quality matters more than quantity.

關於小行星是否算行星的問題，結果是品質比數量更重要。

Seeing the innumerable fascinating but completely inhospitable worlds in our solar system Is a reminder of just how diverse, unique, and

看到太陽系裡無數迷人卻完全不適合居住的世界，提醒了我們地球家園有多麼多元、獨特且

But to keep planet Earth as our home, we have to look after it.

但要守護地球家園，我們必須好好照顧它。

That's why we're working with the nature protection community, Called Planet Wild, Our sponsor for this video.

這就是為什麼我們要和自然保育社群 Planet Wild 合作，他們是本影片的贊助商。

Every month, the Planet Wild community funds a mission to restore the oceans, forests, and

每個月，Planet Wild 社群都會資助一項任務，來復育地球上的海洋、森林和

All of this is documented through videos here on YouTube.

所有這些都會在這裡的 YouTube 影片中記錄下來。

Just like this mission restoring lost peatland ecosystems, you can join in supporting solution oriented missions globally by giving whatever amount you want the first 100 people to sign up using our code, MinutePhysics1 will get their first month covered.

就像這次復育消失泥炭地生態系的任務一樣，你可以加入支持全球以解決方案為導向的任務，捐贈你想要的任何金額，前 100 名使用我們的代碼 MinutePhysics1 註冊的人，他們的第一個月費用將由我們支付。

Just scan this QR code or click the link in the description.

掃描這個 QR 碼或點擊說明中的連結即可。

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小行星為何不是行星的真正原因！ (The REAL Reason Asteroids Aren't Planets)

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