2. 外语
  3. The recently announced discovery of the first known planet orbiting a pulsar (the ultradense, pulsating remnant off the supernov

The recently announced discovery of the first known planet orbiting a pulsar (the ultradense, pulsating remnant off the supernov

admin2021-03-28  71
问题     The recently announced discovery of the first known planet orbiting a pulsar (the ultradense, pulsating remnant off the supernova explosion of a star) turned out to be based on faulty data. Had this discovery been confirmed, theorists would have had difficulty accounting for the existence of such a planet. The supernova would certainly have destroyed any preexisting planets. This particular pulsar is relatively young, allowing little time for a new planet to have coalesced, and it rotates relatively slowly, implying that it has not interacted with any nearby star since the supernova.
    But newer evidence of a different pulsar with planets is more promising. This is a rapidly spurring “millisecond pulsar" thought to be a much older object that has pulled gaseous material from a stellar neighbor, causing its rotational speed to increase. Leftover, unconsumed gas around such a pulsar could, in theory, coalesce into planets. Or the pulsar’s radiation might have vaporized a companion star, providing new material for planetary formation.
Which of the following can be inferred regarding the pulsar discussed in the first paragraph?
选项 A、Theorists initially doubted its existence.
B、If its existence had been confirmed, astronomers would have turned their attention to the pulsar discussed in the second paragraph.
C、If the supernovas explosions that created it had been more powerful the resulting radiation would have preceded the subsequent formation of a planet.
D、If it had interacted with a nearby star since the supernova explosion, it would rotate faster than it does.
E、Astronomers’ interest in it ultimately led to a new theory of planetary formation.
答案D
解析 根据第一段第四句的it rotates relatively slowly，implying that it has not interacted with any nearby star since the supernova可以推测出，如果脉冲星和周围恒星发生相互作用，就会转得更快。A项脉冲星的存在是客观事实，没人质疑这一点，A项质疑的是脉冲星附近的行星。B项文中未提及。C项根据第二段，脉冲星的辐射会促使行星的形成，而非超新星的辐射。E项行星形成的理论和天文学家的兴趣无关。
转载请注明原文地址:https://kaotiyun.com/show/6LVO777K
本试题收录于： GRE VERBAL题库GRE分类
0

GRE VERBAL

GRE

相关试题推荐
随机试题
最新回复(0)