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2011年最新GMAT考试阅读预测(一)(1)

2010-12-23 
 8. According to the passage, the interaction of a neutrino with other matter can produce

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        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:

  (5) 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. Neu-

  (10) trinos 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

  (15) could provide new information about a wide variety of

  cosmic phenomena and about the history of the uni-

  verse.

  But how can scientists detect a particle that interacts

  so infrequently with other matter? Twenty-five years

  (20) 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,

  (25) capable of detecting cosmic neutrinos, is difficult to co-

  nstruct. 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 pro-

  (30) bability 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

  (35) mass of the ocean. Named DUMAND, for Deep Under-

  water Muon and Neutrino Detector, the project calls for

  placing an array of light sensors at a depth of five kilo-

  meters under the ocean surface. The detecting medium is

  the seawater itself: when a neutrino interacts with a

  (40) 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 sea-

  water above the sensors will shield them from the interf-

  ering effects of other high-energy particles raining down

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