B1 中級 29222 タグ追加 保存
動画の字幕をクリックしてすぐ単語の意味を調べられます!
単語帳読み込み中…
字幕の修正報告
It's proven to be one of the most divisive issues in modern science.
in one stroke, thousands of textbooks were out of date.
In my role as Public Astronomer here in Greenwich, I'm always being asked about Pluto.
Why was it reclassified?
And if it's not a planet anymore, then what on earth can it be?
Right from its discovery, Pluto seemed different from the other planets.
Here at the Royal Observatory, we have records going back for hundreds of years,
and somewhere, we should have a record of the discovery of Pluto.
1917, that's too early... 1987, much too late.
Clyde Tombaugh had been set the specific task of finding a planet,
so when he saw his moving point of light in 1930, what else was he going to think he'd found?
Here we have the President, Council, and Fellows at the Royal Astronomical Society sending the Lowell Observatory
their heartiest congratulations on the great discovery of the Trans-Neptunian planet.
But trouble was brewing from the word go.
Within weeks, Pluto's status was being called into question.
Its eccentric orbit and small mass set it apart from the other planets.
More importantly, some scientists argued that Pluto might not be alone.
Over the decades, our ideas about the formation of the Solar System developed.
It was suggested that the edge of the dust and gas cloud from which our planets formed
would have been too spread out to condense into planets.
Instead, they could be something very different.
Scientists reasoned that there could be hundreds of thousands of icy objects on the edge of the solar system
that had failed to be incorporated into one of the major planets.
They called this region the Kuiper Belt,
and Pluto's status as a planet started to be called into question.
On the fifth of January, 2005, came the fatal blow.
Scientists in California discovered another small moving point of light.
This was Eris, a world they believed was bigger than Pluto.
This was huge news.
The likelihood was, there could be many more large objects out there.
Scientists were faced with a choice: either open the doors to potentially hundreds of new planets,
or Pluto was for the chop.
In 2006, the International Astronomical Union put it to the vote,
and it wasn't good news for Pluto.
The IAU decided that a planet had to be an object in orbit around the sun,
that was massive enough for gravity to squeeze it into a spherical shape,
but also it had to be gravitationally dominant,
and that meant it must have cleared its surrounding region of other similarly sized objects,
but with everything else out there in the Kuiper Belt, this was Pluto's downfall.
So where did this leave Pluto?
The IAU decided to classify it as a dwarf planet.
To many, this would seem as a demotion, but I'm not so sure.
As a planet, it was the last gasp on the edge of the Solar System,
but now it's an exciting example of a brand new class of objects.
Whatever we learn from it will change the way we think about our corner of the galaxy.
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

読み込み中…

Why is Pluto not a planet? - Sky at Night: Pluto Revealed Preview - BBC Four

29222 タグ追加 保存
Joyce Lee 2017 年 11 月 10 日 に公開
お勧め動画
  1. 1. クリック一つで単語を検索

    右側のスプリクトの単語をクリックするだけで即座に意味が検索できます。

  2. 2. リピート機能

    クリックするだけで同じフレーズを何回もリピート可能!

  3. 3. ショートカット

    キーボードショートカットを使うことによって勉強の効率を上げることが出来ます。

  4. 4. 字幕の表示/非表示

    日・英のボタンをクリックすることで自由に字幕のオンオフを切り替えられます。

  5. 5. 動画をブログ等でシェア

    コードを貼り付けてVoiceTubeの動画再生プレーヤーをブログ等でシェアすることが出来ます!

  6. 6. 全画面再生

    左側の矢印をクリックすることで全画面で再生できるようになります。

  1. クイズ付き動画

    リスニングクイズに挑戦!

  1. クリックしてメモを表示

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔