銀星砂 :: 天文講座 :: 再見「九大行星」
Goodbye Nine Planets
:: Lectures :: Astronomy @ Stardust Sand 銀星砂

[2006-10-31]

再見「九大行星」 Goodbye "Nine Planets"

一次演講這講座是七月的事,現在已經是十月。由起初的預告,到現在的報告,確實再見了「九大行星」,但故事的峰迴路轉,至今仍未定案。

The first time I present this lecture is July, now it's October. The talk changed from a preview to a report, now we really said goodbye to "Nine Planets". However, the story is not end yet, and its dramatic story is revealed in the lecture.

[2006-07-25]

1930年冥王星被發現,「九大行星」這名詞一直沿用至今,但很快,「九大行星」這個名稱將會成為歷史,因為國際天文聯會將會重新定義何謂「行星」。

2005年,天體2003 UB313的發現,證實比冥王星還要大,一度傳出「發現第十大行星」的報導,然而事情並非這麼簡單,正如冥王星,這天體跟太陽系內一般的行星有不少相異之處,所以有一批天文學家認為它並不屬行星之列。因此加速牽起一場關於行星定義的爭論,連帶冥王星也有機會被踢出行星之列。

國際天文聯會將於8月的大會中討論這問題,無論結論是什麼,八顆行星還是十顆?還是更多?現在雖不知道,但一件事可以肯定,太陽系不再有九大行星。

Since Pluto discovered in 1930, the term "Nine Planets" have been used for many years, but soon, the term "Nine Planets" will become history, as the International Astronomical Union will formally define what is "planet".

In 2005, an object 2003 UB313 was discovered and found to be larger than Pluto, many reports are claiming the discovery of the "10th Planet". However, the story is not that straight foward, just as same as Pluto, this object are quite different with the other major eight planets in the solar system, therefore some astronomers disagree that it is classified as a planet. Thus a hot debate about what is defined as planet is keep on, as well as the planetary status of Pluto.

The International Astronomical Union will discuss the problem in the coming General Assembly in August. No matter what is their conclusion, 8 or 10 planets, our Solar System would no longer have 9 planets.

Powerpoint::

v2.0 2006-10-25 23.8 MB 浸會大學物理系及天文學會
v1.0 2006-07-21 10.1 MB 可觀自然教育中心暨天文館

Supplementary Material::

Solar System Formation Video 106 MB
IAU Discussion on the definition of a Planet Streaming Video
IAU Voting on the final definition Streaming Video

Powerpoint snapshot of v2.0::

Recording Playback of 2006-07-21::

Further Readings ::

Headline - 失去冥王星的一天 同時是新紀元的開始
Headline - 行星定義第三稿草案 降格冥王星為"矮行星"
Headline - 太陽系行星數目將增至十二顆
Book - Beyond Pluto



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