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  • 望远镜

    A telescope pointing towards a swirling galaxy in the night sky, showcasing cosmic wonders.
     

    What would Galileo think of the things we can see through a telescope?
    ::伽利略会从望远镜上看到什么?

    The earliest telescopes could see about as much as a regular pair of binoculars today. Galileo was probably the first person to see Jupiter’s four largest moons, which cannot be seen with the naked eye. As telescopes became more powerful, scientists could see even more- we now know that   has over 80 moons! Galileo would be astonished to see all of Jupiter's moons. And imagine what he would think of the galaxies!
    ::如今,最早的望远镜可以看到与普通双筒望远镜一样多的望远镜。 伽利略可能是第一个看到木星四大卫星的人,这四大卫星无法用肉眼看到。 随着望远镜变得更加强大,科学家们可以看到更多——我们现在知道它有80多颗卫星!伽利略将惊讶地看到木星的所有卫星。想象一下他会如何看待星系!

    Types of Telescopes
    ::望远镜类型

    Humans have been making and using magnifying lenses for thousands of years. The first telescope was built in 1608 by a Dutch lens maker, who called it a “Perspective Glass”. The following  year , Italian scientist and mathematician Galileo Galilei (1564–1642) built his own  model  and began to use it to study the  stars , moon, and  planets . These early telescope used two lenses to make distant objects appear both nearer and larger. Galileo subsequently made many improvements to telescope design.
    ::数千年来,人类一直在制造和使用放大镜。 第一台望远镜是1608年由荷兰镜头制造者建造的,他称其为“视觉玻璃 ” 。 次年,意大利科学家和数学家伽利略·加利利(Galilei Galilei )(1564-1642 ) , 建造了自己的模型,并开始用它研究恒星、月亮和行星。 这些早期望远镜使用两颗镜使遥远的天体更近、更宽。 伽利略随后对望远镜的设计做了许多改进。

    Optical Telescopes
    ::光学望远镜

    Telescopes that use lenses to bend light are called  refracting telescopes , or refractors ( Figure   ). The earliest telescopes were all refractors. Many amateur  astronomers  still use refractors today. Refractors are good for viewing details within our  solar system . Craters on the surface of Earth’s Moon or the rings around   are two such details.
    ::使用透镜来弯曲光线的望远镜被称为回折望远镜或相向望远镜(图 ) 。 最早的望远镜都是再折器 。 许多业余天文学家今天仍然使用反相器 。 反相器有利于在太阳系内查看细节 。 地球月球表面或环形圈上的撞击器就是两个这样的细节 。

    Optical telescope housed indoors, showcasing its large cylindrical structure and reflective elements.
     
    Refracting telescopes can be very large.

    Around 1670, Sir Isaac Newton built a different kind of telescope. Newton's telescope used curved mirrors instead of lenses to  focus  light. This type of telescope is called a  reflecting telescope , or reflector.
    ::大约1670年,艾萨克·牛顿爵士建造了另一种望远镜,牛顿的望远镜使用弯曲反射镜而不是透镜来聚焦光。这种望远镜被称为反射望远镜或反射器。

    It’s much easier to precisely make mirrors than to precisely make glass lenses. Mirrors are also much lighter than heavy glass lenses. For these two reasons, mirrors can be made larger than lenses. This is important because a reflecting telescope can be made much larger. Larger telescopes can collect more light. This means that they can study dimmer or more distant objects. The largest optical telescopes in the world today are reflectors. Telescopes also can be made to use both lenses and mirrors.
    ::准确制作镜子比精确制作玻璃镜要容易得多。 镜子比重玻璃镜要轻得多。 由于这两个原因,镜子可以比镜子大得多。 这很重要,因为反射望远镜可以大得多。 更大的望远镜可以收集更多的光。 这意味着它们可以研究沉积或更远的物体。 当今世界最大的光学望远镜是反射器。 望远镜也可以同时使用镜子和镜子。

    Radio Telescopes
    ::无线电望远镜

    Radio telescopes  collect  radio waves . These telescopes are even larger telescopes than reflectors. Radio telescopes look a lot like  satellite  dishes. In  fact , both are designed to collect and focus radio waves or microwaves from space.
    ::射电望远镜收集无线电波,这些望远镜比反射望远镜还大,射电望远镜与卫星天线非常相似,事实上,两者的设计都是为了从空间收集和聚焦无线电波或微波。

    Many radio telescopes are so large that they must be built into natural depressions in the ground in order to support their weight. At 305 m (1000 ft) in diameter, the  radio telescope  at the Arecibo Observatory in Puerto Rico ( Figure  ) was the largest single telescope in the world at the time of its construction in 1963.  Unfortunately, in 2020, failure of some of the support cables caused the massive dish to collapse. Because it was built into the ground, the Arecibo telescope could only observe the part of the sky that happens to be overhead at a given time.  The Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China has a similar design, but a considerably wider field of view.
    ::许多射电望远镜如此之大,必须安装在地面的自然抑郁中以支撑其重量。直径为305米(1 000英尺)时,波多黎各的阿雷西博天文台(Figore ) 的射电望远镜是1963年建造时世界上最大的一台望远镜。不幸的是,在2020年,一些支撑电缆的故障导致大型天线崩溃。由于它建在地上,阿雷西博天文望远镜只能观测在特定时间碰巧是高空的那部分天空。 中国的五百公尺光谱射电望远镜(FAST)的设计类似,但视野也大得多。

    Aerial view of the Arecibo Observatory's large radio telescope before its collapse.
     
    The radio telescope at the Arecibo Observatory in Puerto Rico as it appeared when it was still operational in 2012

    A group of radio telescopes can be linked together with a computer. The telescopes observe the same object. The computer then combines the  data  from each telescope. This makes the group function like one single telescope. An example is pictured below ( Figure ).
    ::一组射电望远镜可以与计算机连接。 望远镜观测的是同一个对象。 然后计算机将每个望远镜的数据合并在一起。 这就使得该组的功能像一个望远镜一样。 一个例子在下面( 图) 绘制( 图 ) 。

    Group of radio telescopes in a desert landscape, used for astronomical observations.
     
    The Very Large Array in New Mexico consists of 27 radio telescopes.

    Space Telescopes
    ::空间望远镜

    Telescopes on Earth all have one big problem: incoming light must pass through the  atmosphere . This blocks some  wavelengths  of radiation. Also, motion in the atmosphere distorts light. You see this when you see stars twinkling in the night sky. Many observatories are built on high  mountains . There is less air above the telescope, so there is less interference from the atmosphere.  Space telescopes  avoid problems from the atmosphere completely since they  orbit  outside the atmosphere.
    ::地球上的望远镜都有一个大问题: 进入的光线必须穿过大气层。 它会阻断一些辐射波长。 另外, 在大气中运动会扭曲光。 当你看到恒星在夜空中闪烁时, 你可以看到这一点。 许多观测台都建在高山上。 望远镜上方的空气较少, 因而大气的干扰较少。 空间望远镜可以完全避免大气层的问题, 因为它们在大气层之外运行 。

    The Hubble  Space Telescope  ( Figure ) is the best known space telescope. Hubble began operations in 1990. Since then, it has provided huge amounts of data. The telescope has helped astronomers answer many of the biggest questions in  astronomy .
    ::哈勃空间望远镜(图)是最著名的空间望远镜,哈勃于1990年开始运行,自那时以来,它提供了大量数据。望远镜帮助天文学家回答了天文学中许多最大的问题。

    A detailed view of the Hubble Space Telescope in orbit around Earth.
     
    The Hubble Space Telescope has opened up the Universe to human observation.

    In years following Hubble’s launch, The National Aeronautics and Space Administration (NASA) created the “Great Observatories”.  This consisted of three other major space telescopes, each using a different part of the  electromagnetic spectrum .  Dozens of other space telescopes have been launched by agencies around the world. The James Webb Space Telescope launched in 2021 to replace the aging Hubble.
    ::哈勃发射后的几年里,国家航空和航天局(美国航天局)创建了“大天文台 ” ( 大天文台 ) , 由另外三台主要空间望远镜组成,每个望远镜使用电磁频谱的不同部分,世界各地机构也发射了数十台其他空间望远镜。 詹姆斯·韦伯空间望远镜于2021年发射,以取代老的哈勃望远镜。

    Star cluster captured by a space telescope, showing points of light in the universe.
     
    Stars in the star cluster appear as points of light. Observations like these must be made with a space telescope.

    Summary
    ::摘要

    • Refracting and reflecting telescopes are optical telescopes that use lenses to gather light.
      ::折射和反射望远镜是光学望远镜,使用透镜收集光。
    • Radio telescopes collect radio waves and are sometimes used in large arrays.
      ::无线电望远镜收集无线电波,有时用于大型阵列。
    • Space telescopes can see much more than Earth-bound telescopes, since the atmosphere doesn’t affect their information.
      ::太空望远镜比地球望远镜能看得更远, 因为大气层不会影响它们的信息。

    Review
    ::回顾

    1. What type of telescope was the first to be developed? Why was it the first?
      ::哪种望远镜是第一种开发的?为什么是第一种?
    1. Why are most telescopes refracting telescopes?
      ::为什么大多数望远镜都是反折射望远镜?
    1. Why do scientists need space telescopes?
      ::为什么科学家需要空间望远镜?

    Explore More
    ::探索更多

    Use this resource to answer the questions that follow.
    ::使用此资源回答下面的问题 。

    1. Where were telescopes developed?
      ::哪里开发了望远镜?
    1. What did Galileo do for the telescope?
      ::伽利略对望远镜做了什么?
    1. What was the old belief about the Moon and other celestial bodies?
      ::月球和其他天体的旧信仰是什么?
    1. List Galileo's discoveries with the telescope.
      ::列出伽利略与望远镜的发现
    1. Explain Galileo's conflict with the Roman Catholic Church.
      ::解释一下伽利略和罗马天主教会的冲突