<sub id="17vpx"></sub>

      <progress id="17vpx"></progress>
      <big id="17vpx"><progress id="17vpx"><meter id="17vpx"></meter></progress></big><big id="17vpx"><progress id="17vpx"></progress></big><big id="17vpx"><sub id="17vpx"></sub></big>

      英語聽力 學英語,練聽力,上聽力課堂! 注冊 登錄
      > 在線聽力 > 英語高級聽力 > 經濟學人(中英對照+MP3) >  第3259課

      2020年經濟學人 物理學家弗里曼·戴森(3)






      In 1958 he was briefly lured away from his professorship at the IAS to work on Project Orion: a plan to build a rocket, propelled by nuclear power, that would be faster and more efficient than any other. The basic principle was to throw a stream of nuclear bombs out of the back of the rocket, detonate them, and ride the shockwaves to Mars and beyond. On paper, it seemed to work. Flight tests on small models, using conventional explosives, were encouraging.


      Orion could reach Mars in weeks, where chemical rockets would take six months or more. A more powerful version could cross the vast void to Alpha Centauri, the nearest star to the sun, in a bit over a century. Since the bigger the rocket, the more efficient it was, he proposed a 240m-ton ship 90 miles in diameter, designed to carry thousands of colonists and make humanity an interstellar species. Whether he was serious, even he may not have known.


      The project was scuppered in the end by a mix of political queasiness over the fallout (rather literally—later modelling suggested that each launch of a modestly-sized rocket from Earth's surface would kill about ten people) and the partial test ban treaty of 1963, which forbade nuclear explosions except underground. He was involved in that too, arguing in favour of the ban, in his clipped home-counties tones, in front of America's Senate. Since the power they had unleashed thrust physicists into high places, he also became a government adviser on science and grand strategy.



      瘋狂英語 英語語法 新概念英語 走遍美國 四級聽力 英語音標 英語入門 發音 美語 四級 新東方 七年級 賴世雄 zero是什么意思

      • 頻道推薦
      • |
      • 全站推薦
      • 廣播聽力
      • |
      • 推薦下載
      • 網站推薦