万物简史 第24期:走进太阳系(2)(在线收听

   This was actually something of a blow to Pluto's status as a planet, which had never been terribly robust anyway. Since previously the space occupied by the moon and the space occupied by Pluto were thought to be one and the same, it meant that Pluto was much smaller than anyone had supposed—smaller even than Mercury. Indeed, seven moons in the solar system, including our own, are larger.

  这对冥王星的行星地位实际上是个打击,而这个地位又从来没有牢固过。原先认为,那颗卫星占有的和冥王星占有的是同一个空间。这意味着,冥王星比任何人想像的要小得多--比水星还要小。实际上,太阳系里的七颗卫星,包括我们地球的卫星,都要比冥王星的卫星大。
  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 partly a matter of what their instruments are designed to detect, and partly it's just Pluto. Mostly it's where they point their instruments. In the words of the astronomer Clark Chapman: "Most people think that astronomers get out at night in observatories and scan the skies. That's not true. Almost all the telescopes we have in the world are designed to peer at very tiny little pieces of the sky way off in the distance to see a quasar or hunt for black holes or look at a distant galaxy. The only real network of telescopes that scans the skies has been designed and built by the military."此刻,你自然会问,为什么发现我们自己太阳系里的一颗卫星要花那么长的时间。回答是:这跟天文学家把仪器对准什么地方、他们的仪器旨在探测什么东西有关系,也跟冥王星本身有关系。最重要的是他们把仪器对准什么地方。用天文学家克拉克·查普曼的话来说:"大多数人认为,天文学家在夜间去天文台扫视天空。这是不真实的。世界上差不多所有的望远镜都旨在观察遥远天空中的极小东西,观察一颗类星体,或寻找黑洞,或观察一个遥远的星系。惟一真正用来扫视天空的望远镜网络是由军方设计和制造的。"We have been spoiled by artists' renderings into imagining a clarity of resolution that doesn't exist in actual astronomy. Pluto in Christy's photograph is faint and fuzzy—a piece of cosmic lint—and its moon is not the romantically backlit, crisply delineated companion orb you would get in a National Geographic painting, but rather just a tiny and extremely indistinct hint of additional fuzziness. Such was the fuzziness, in fact, that it took seven years for anyone to spot the moon again and thus independently confirm its existence.
  我们受了艺术家艺术表达的不良影响,以为图像的清晰度很高,这在天文学里其实是不存在的。在克里斯蒂的照片上,冥王星暗淡无光,非常模糊--只是一片宇宙绒花--它的卫星并不像你会在美国《国家地理杂志》上看到的那种球体:背景很亮,非常浪漫,线条清晰,陪伴着冥王星;而只是小小的、极其模糊的一团。事实上,正是由于这种模糊,人们过了7年时间才再次见到那颗卫星,从而确认它的独立存在。
 
  原文地址:http://www.tingroom.com/lesson/syysdw/wwwjs/349324.html