萬物簡史 第24期:走進太陽系(2)

This was actually something of a blow to Pluto'sstatus as a planet, which had never been terriblyrobust anyway. Since previously the spaceoccupied by the moon and the space occupied byPluto were thought to be one and the same, it meantthat Pluto was much smaller than anyone hadsupposed—smaller even than Mercury. Indeed, sevenmoons in the solar system, including our own, arelarger.

這對冥王星的行星地位實際上是個打擊，而這個地位又從來沒有牢固過。原先認為，那顆衛(wèi)星占有的和冥王星占有的是同一個空間。這意味著，冥王星比任何人想像的要小得多--比水星還要小。實際上，太陽系里的七顆衛(wèi)星，包括我們地球的衛(wèi)星，都要比冥王星的衛(wèi)星大。

Now a natural question is why it took so long for anyone to find a moon in our own solar system.The answer is that it is partly a matter of where astronomers point their instruments and partlya matter of what their instruments are designed to detect, and partly it's just Pluto. Mostly it'swhere they point their instruments. In the words of the astronomer Clark Chapman: "Mostpeople think that astronomers get out at night in observatories and scan the skies. That's nottrue. Almost all the telescopes we have in the world are designed to peer at very tiny littlepieces of the sky way off in the distance to see a quasar or hunt for black holes or look at adistant galaxy. The only real network of telescopes that scans the skies has been designedand built by the military."

此刻，你自然會問，為什么發(fā)現(xiàn)我們自己太陽系里的一顆衛(wèi)星要花那么長的時間。回答是：這跟天文學家把儀器對準什么地方、他們的儀器旨在探測什么東西有關系，也跟冥王星本身有關系。最重要的是他們把儀器對準什么地方。用天文學家克拉克·查普曼的話來說："大多數(shù)人認為，天文學家在夜間去天文臺掃視天空。這是不真實的。世界上差不多所有的望遠鏡都旨在觀察遙遠天空中的極小東西，觀察一顆類星體，或尋找黑洞，或觀察一個遙遠的星系。惟一真正用來掃視天空的望遠鏡網(wǎng)絡是由軍方設計和制造的。"

We have been spoiled by artists' renderings into imagining a clarity of resolution that doesn'texist in actual astronomy. Pluto in Christy's photograph is faint and fuzzy—a piece of cosmiclint—and its moon is not the romantically backlit, crisply delineated companion orb you wouldget in a National Geographic painting, but rather just a tiny and extremely indistinct hint ofadditional fuzziness. Such was the fuzziness, in fact, that it took seven years for anyone tospot the moon again and thus independently confirm its existence.

我們受了藝術家藝術表達的不良影響，以為圖像的清晰度很高，這在天文學里其實是不存在的。在克里斯蒂的照片上，冥王星暗淡無光，非常模糊--只是一片宇宙絨花--它的衛(wèi)星并不像你會在美國《國家地理雜志》上看到的那種球體：背景很亮，非常浪漫，線條清晰，陪伴著冥王星;而只是小小的、極其模糊的一團。事實上，正是由于這種模糊，人們過了7年時間才再次見到那顆衛(wèi)星，從而確認它的獨立存在。