Giuseppe Piazzi, a priest in Palermo, Italy, was mapping the stars in the sky.

朱塞佩·皮亞齊，一個在義大利巴勒莫的神父正畫著星星的位置。

Over three nights, he'd look at and draw the same set of stars, carefully measuring their relative positions.

三天夜晚，他都觀察同一組星星，仔細量測它們的相對位置。

That night, he measured the stars.

那晚他量了星星的距離。

The next night, he measured them again.

次日他又量了一次。

To his surprise, one had moved.

他驚訝地發現其中一顆星星動了。

The third night, the peculiar star had moved again.

第三晚那顆奇特的星又動了。

This meant it couldn't be a star at all.

這表示那絕對不是顆恆星。

It was something new, the first asteroid ever discovered, which Piazzi eventually named Ceres.

那是全新的，首顆被發現的小行星，後來皮亞齊稱它為「穀神星」。

Asteroids are bits of rock and metal that orbit the Sun.

小行星是繞太陽轉的石頭和金屬。

At over 900 kilometers across, Ceres is a very large asteroid.

直徑超過 900 公里的穀神星算是較大的小行星。

But through a telescope like Piazzi's, Ceres looked like a pinpoint of light, similar to a star.

但透過像皮亞齊那樣的望遠鏡看，穀神星只像恆星那樣的一小點亮光。

In fact, the word asteroid means star-like.

事實上在義大利文中，小行星的意思就是像星星一樣。

You can tell the difference between stars and asteroids by the way they move across the sky.

分辨小行星與恆星可用二者在星空中的移動方式來判別。

Of course, Piazzi knew none of that at the time, just that he had discovered something new.

不過那時的皮亞齊當然完全不曉得，只知道他找到新東西。

To learn about Ceres, Piazzi needed to track its motion across the sky and then calculate its orbit around the Sun.

為了瞭解穀神星，皮亞齊必須追蹤它在星空中的行進路線，然後計算出它繞行太陽的軌道。

So each clear night, Piazzi trained his telescope to the heavens.

所以每個晴朗的夜晚，皮亞齊都用望遠鏡觀察天空。

Night after night, he made careful measurements until finally, he couldn't.

每個夜晚精準測量，直到他不能這麼做為止。

The Sun got in the way.

因為太陽擋住穀神星了。

When Piazzi first spotted Ceres, it was here, and the Earth was here.

皮亞齊第一次看到穀神星時，它在這個位置，地球在這裡。

As he tracked it each night, the Earth and Ceres moved like this until Ceres was here.

在夜夜觀察穀神星的軌跡後，他發現地球和穀神星是這麼動的，直到穀神星到了這個位置。

And that meant that Ceres was only in the sky when it was daytime on Earth.

也就是白天穀神星才在地球的上空。

During the day, bright sunlight made this small asteroid impossible to see.

因為陽光太強烈而無法在白天看見它，

Astronomers needed to calculate Ceres's orbit.

天文學家必須計算穀神星的軌道。

This would let them predict where it was going to be in the vast night sky on any given night.

才能夠預測任何一晚穀神星在廣袤夜空中的位置。

But the calculations were grueling and the results imprecise.

但他們計算出來的結果慘不忍睹、錯得離譜。

Many astronomers searched for Ceres, but not knowing exactly where to look, no one could find it.

很多天文學家都在找穀神星，卻不知其正確位置，所以沒人找得到。

Luckily, a hardworking mathematician named Carl Friedrich Gauss heard about the lost asteroid.

還好，一個勤奮的數學家卡爾·弗里德里希·高斯得知失蹤的小行星一事後，

He thought it was an exciting puzzle and went to work.

開始解這個他認為是帶勁的謎題。

When he realized he didn't have the mathematical methods he needed, he invented new ones that we still use today.

當他發現沒有現成可用的數學公式時，就自己發明我們今天仍使用的新公式。

He derived a new orbit and new predictions of where to look for Ceres.

他算出穀神星的全新預測軌道。

Hungarian astronomer Baron Franz Xaver von Zach searched for Ceres with Gauss's predictions.

匈牙利的天文學家弗朗茨·薩維爾·馮札克男爵用高斯的預測來尋找穀神星。

After weeks of frustrating clouds, von Zach finally had clear skies on December 31,1801.

在幾個禮拜令人氣惱的陰天之後，馮札克終於在 1801 年 12 月 31 日等到了晴空。

He looked through his telescope and finally saw Ceres.

他透過望遠鏡終於找到穀神星。

We haven't lost track of it since.

至今我們一直掌握著它的行蹤。

Today, we've discovered hundreds of thousands of asteroids.

現今我們已找到了數十萬顆小行星。

Many, including Ceres, orbit the Sun between Mars and Jupiter, while near-Earth asteroids orbit the Sun relatively close to Earth.

連穀神星在內，其中多顆位於火星與木星之間，繞著太陽轉，而另有些在地球附近繞著太陽轉。

When we recorded this narration, astronomers had discovered 16,407 near-Earth asteroids,

在我們為這影片配音時，天文學家已經發現了 16,407 顆近地小行星，

but since we find new asteroids all the time, that number will have grown by hundreds or thousands by the time you watch this.

但由於我們一直在尋找新的小行星，當你看這部影片的時候，這個數字將已增長了數以百計或數以千計。

Today, asteroid hunters use modern telescopes, including one in space.

現今的小行星獵人使用現代的望遠鏡，其中包括一個太空望遠鏡。

Computers analyze the images, and humans check the output before reporting the asteroid observations to an archiving center.

電腦分析圖像，人檢查電腦的輸出，然後把小行星的觀測報告交給檔案中心。

Each discovered asteroid has its unique orbit measured.

每個已發現小行星的獨特軌道都被量測過。

An orbit lets astronomers predict where asteroids are going to be at any given time.

小行星的軌道讓天文學家得以預測它在任何特定時間的出現位置。

Most asteroid trajectories can be predicted for about 80 years though we can calculate where the best studied asteroids will be every day between now and 800 years into the future.

我們能預測大多數小行星未來約 80 年的軌跡，而能為那些最多人研究過的小行星算出從現在起的八百年間每天的位置。

We must keep searching for asteroids in case there's one out there on a collision course with Earth.

我們必須不斷尋找小行星，以防有一天某一顆會撞上地球。

Astronomers don't only search for asteroids, though.

不過天文學家不僅尋找小行星。

They also study them to learn how they formed, what they're made of, and what they can tell us about our solar system.

也研究它們如何形成，由什麼組成，以及能告訴我們關於太陽系些什麼。

Today, we can do something that Piazzi could only dream of: send spacecraft to study asteroids up close.

我們今日能做一些皮亞齊以前只能夢想的事情：派太空船去近距離研究小行星。

One spacecraft called Dawn journeyed billions of kilometers over four years to the main asteroid belt.

曾有一艘名為「曙光號」的太空船在四年間航行了數十億公里。

There, it visited Ceres and another asteroid, Vesta.

去到主要的小行星帶。

Dawn's stunning images transformed Piazzi's dot of light into a spectacular landscape of craters, landslides, and mountains.

在那裡，它探訪了穀神星和另一個小行星「灶神星」，曙光號令人驚艷的圖像把皮亞齊的一小點亮光轉化為壯觀的隕石坑、山體滑坡。

The author of this lesson is a Ted speaker, and full-time asteroid hunter.

這門課的作者是一位 Ted 講者，也是全職的小行星獵人。

In other word, she's a total bad a**.

換句話說，她完全是個狠角色。

Carrie has written a fascinating book about her work and we're thrilled to add it to the Ted-Ed book rec list.

Carrie 就她的工作著作了一本引人入勝的書，我們很高興將其加進 Ted-Ed 的推薦書單中。

Thanks for watching and thanks for your support.

感謝你的收看及支持。