Virtually everything astronomers known about objects outside the solar system is based on the detection of photons—quanta of electromagnetic radiation. Yet there is another form of radiation that permeates the universe: neutrinos. With (as its name implies) no electric charge, and negligible mass, the neutrino interacts with other particles so rarely that a neutrino can cross the entire universe, even traversing substantial aggregations of matter, without being absorbed or even deflected. Neutrinos can thus escape from regions of space where light and other kinds of electromagnetic radiation are blocked by matter. Furthermore, neutrinos carry with them information about the site and circumstances of their production: therefore, the detection of cosmic neutrinos could provide new information about a wide variety of cosmic phenomena and about the history of the universe.
But how can scientists detect a particle that interacts so infrequently with other matter? Twenty-five years passed between Pauli’s hypothesis that the neutrino existed and its actual detection: since then virtually all research with neutrinos has been with neutrinos created artificially in large particle accelerators and studied under neutrino microscopes. But a neutrino telescope, capable of detecting cosmic neutrinos, is difficult to construct. No apparatus can detect neutrinos unless it is extremely massive, because great mass is synonymous with huge numbers of nucleons (neutrons and protons), and the more massive the detector, the greater the probability of one of its nucleon’s reacting with a neutrino. In addition, the apparatus must be sufficiently shielded from the interfering effects of other particles.
Fortunately, a group of astrophysicists has proposed a means of detecting cosmic neutrinos by harnessing the mass of the ocean. Named DUMAND, for Deep Underwater Muon (muon: n. μ介子) and Neutrino Detector, the project calls for placing an array of light sensors at a depth of five kilometers under the ocean surface. The detecting medium is the seawater itself: when a neutrino interacts with a particle in an atom of seawater, the result is a cascade of electrically charged particles and a flash of light that can be detected by the sensors. The five kilometers of seawater above the sensors will shield them from the interfering effects of other high-energy particles raining down through the atmosphere.
The strongest motivation for the DUMAND project is that it will exploit an important source of information about the universe. The extension of astronomy from visible light to radio waves to x-rays and gamma rays never failed to lead to the discovery of unusual objects such as radio galaxies, quasars, and pulsars. Each of these discoveries came as a surprise. Neutrino astronomy will doubtless bring its own share of surprises.
1. Which of the following titles best summarizes the passage as a whole?
(A) At the Threshold of Neutrino Astronomy
(B) Neutrinos and the History of the Universe
(C) The Creation and Study of Neutrinos
(D) The DUMAND System and How It Works（A）
(E) The Properties of the Neutrino
又是主题题。 对threshold 的意义很难理解。 是开始或开端的意思吧？ 可是怎样从文章中推出这个 结论呢？ 请nn 指教。
我不是nn，说一下自己做这道题的思路，欢迎指正
第一段说“有中微子这种东西，它可以用来研究宇宙”
第二段说“中微子很难被探测”
第三段说“某种可以探测中微子方法”
最后一段说“研究中微子的意义”
全文总的来讲，围绕“中微子对于天文的意义以及如何实现这一意义”来讲的。
b：History of the Universe文中没说
c：The Creation of Neutrinos文中没说
d：The DUMAND System 是个细节
e：The Properties of the Neutrino同样是细节
我不是nn，说一下自己做这道题的思路，欢迎指正
第一段说“有中微子这种东西，它可以用来研究宇宙”
第二段说“中微子很难被探测”
第三段说“某种可以探测中微子方法”
最后一段说“研究中微子的意义”
全文总的来讲，围绕“中微子对于天文的意义以及如何实现这一意义”来讲的。
b：History of the Universe文中没说
c：The Creation of Neutrinos文中没说
d：The DUMAND System 是个细节
e：The Properties of the Neutrino同样是细节
threshold恐怕不能从文章中某个句子改写得来。第二段第二句和第三段首句合在一起，则可以得出：开发出一种可以探测中微子的方法是一个里程碑式的事件。
我想，可以通过这种理解得出threshold。
欢迎指正！
这样啊， 谢谢！！
我不是nn，说一下自己做这道题的思路，欢迎指正
第一段说“有中微子这种东西，它可以用来研究宇宙”
第二段说“中微子很难被探测”
第三段说“某种可以探测中微子方法”
最后一段说“研究中微子的意义”
全文总的来讲，围绕“中微子对于天文的意义以及如何实现这一意义”来讲的。
b：History of the Universe文中没说
c：The Creation of Neutrinos文中没说
d：The DUMAND System 是个细节
e：The Properties of the Neutrino同样是细节
History of University is mentioned at the end of the first paragraph, I think
Furthermore, neutrinos carry with them information about the site and circumstances of their production: therefore, the detection of cosmic neutrinos could provide new information about a wide variety of cosmic phenomena and about the history of the universe.
人家只不过把题目弄得有文学味嘛
3. In the last paragraph, the author describes the
development of astronomy in order to
(A) suggest that the potential findings of neutrino
astronomy can be seen as part of a series of
astronomical successes
(B) illustrate the role of surprise in scientific discovery
(C) demonstrate the effectiveness of the DUMAND
apparatus in detecting neutrinos
(D) name some cosmic phenomena that neutrino
astronomy will illuminate
(E) contrast the motivation of earlier astronomers with
that of the astrophysicists working on the
DUMAND project
这题有点犹豫。主要是对最后一段那些X-ray什么的放在这里的作用不清楚。答案是A，我选的C。最后一段最后两句话的意思是不是这样的？前面提到的那些发现都曾经是surprise( 言外之意现在解决了） Neutrino astronomy 也带来了这样的surprise(言外之意也解决了）因此选A。。对么？？
结合整片文章看，最后一段，作用是说明有效地探测中子给宇宙历史发现带来的重要性，而并不是说DUMAND 的effectiveness
The extension of astronomy from visible light to radio waves to x-rays and gamma rays never failed to lead to the discovery of unusual objects such as radio galaxies, quasars, and pulsars. Each of these discoveries came as a surprise. Neutrino astronomy will doubtless bring its own share of surprises
说X ray 等东西就是来支持，最后一段的结论 will exploit an important source of information about the universe
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