其实SAT阅读的备考练习中,大家也要多进行真题的练习,毕竟通过这些内容的练习,能够辅助我们更好的来提高分数。那么具体的备考练习中,哪些真题内容更值得大家来借鉴复习呢?下面小编为大家整理了详细的内容,供大家参考!

  Overview/Dark Energy

  Dark energy is best known as the putative agent of cosmic acceleration—an unidentified substance that exerts a kind of antigravity force on the universe as a whole.

  Less well known is that dark energy also has secondary effects on material within the universe. It helped to imprint the characteristic filigree pattern of matter on large scales. On a smaller scale, it appears to have choked off the growth of galaxy clusters some six billion years ago.

  On a still smaller scale, dark energy has reduced the rate at which galaxies yank on, bang into and merge with one another. Such interactions shape galaxies. Had dark energy been weaker or stronger, the Milky Way might have had a lower star formation rate, so the heavy elements that constitute our planet might never have been synthesized.

  Overview/Dark Energy

  Dark energy is best known as the putative agent of cosmic acceleration—an unidentified substance that exerts a kind of antigravity force on the universe as a whole.

  Less well known is that dark energy also has secondary effects on material within the universe. It helped to imprint the characteristic filigree pattern of matter on large scales. On a smaller scale, it appears to have choked off the growth of galaxy clusters some six billion years ago.

  On a still smaller scale, dark energy has reduced the rate at which galaxies yank on, bang into and merge with one another. Such interactions shape galaxies. Had dark energy been weaker or stronger, the Milky Way might have had a lower star formation rate, so the heavy elements that constitute our planet might never have been synthesized.

  EVIDENCE FOR DARK ENERGYScientificAmerican:

  SUPERNOVA E XPLOSIONS

  In an expanding universe, galaxies move apart at a speed that depends on the distance between them. Supernovae offer a way to measure this effect: their spectral redshift reveals the speed of their host galaxies, and their brightness reveals distance. It turns out that galaxies billions of years ago were moving slower than a simple extrapolation from the current rate of expansion would imply. The expansion rate must have increased over that time—the hallmark of dark energy.

  COSMIC MICROWAVE BACKGROUND R ADIATION

  Images of the background radiation contain spots whose apparent size reflects the overall geometry of space and therefore the density of the universe. This quantity exceeds the amount of matter (both ordinary and exotic), so a missing component such as dark energy must make up the difference. In addition, the background radiation has been slightly reworked by the gravitational fields of cosmic structures. The amount of reworking depends on how the expansion rate has changed over time and matches what dark energy would do.

  GAL A X Y CONFIGUR ATION

  Galaxies are not sprinkled randomly through the heavens. Instead they are arranged in patterns, one of which resembles the spots in the microwave background. It can be used to measure the total mass of the universe and confirm the need for dark energy.

  GR AVITATIONAL LENSING

  A lump of mass can serve as a lens; its gravity bends light. Such a lens can produce multiple images, like a fun-house mirror, if the light source is directly behind it—an alignment that becomes more probable the bigger the universe is, which in turn depends on the amount of dark energy. A weaker lens can still bend light by a small angle that depends on its mass. Studies of this process have revealed how clumps of matter have grown over time and found the imprint of dark energy.

  GAL A X Y CLUS TERS

  X-ray observations trace the evolution of the mass of galaxy clusters.

  Dark energy is required to explain when and how they formed.

  以上就是关于“老SAT阅读资料练习内容”的内容,希望通过上述内容的学习,大家能够更好的利用这些阅读资料,来提高我们的阅读能力。


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