The Hubble Telescope A Since the earliest days of astronomy, since the time of Galileo, astronomers have shared a single goal -- to see more, see farther, see deeper. The Hubble Space Telescope's launch in 1990 sped humanity to one of its greatest advances in that journey. Hubble is a telescope that orbits Earth. Its position above the atmosphere, which distorts and blocks the light that reaches our planet, gives it a view of the universe that typically far surpasses that of ground-based telescopes. Hubble is one of NASA's most successful and long-lasting science missions. It has beamed hundreds of thousands of images back to Earth, shedding light on many of the great mysteries of astronomy. Its gaze has helped determine the age of the universe, the identity of quasars ( 类星体 ), and the existence of dark energy. B Hubble's discoveries have transformed the way scientists look at the universe. Its ability to show the universe in unprecedented detail has turned astronomical conjectures ( 猜想 ) into concrete certainties. It has winnowed down ( 筛选 ) the collection of theories about the universe even as it sparked new ones, clarifying the path for future astronomers. C Among its many discoveries, Hubble has revealed the age of the universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. Hubble played a key role in the discovery of dark energy, a mysterious force that causes the expansion of the universe to accelerate. D Hubble has shown scientists galaxies ( 星系 ) in all stages of evolution, including toddler galaxies that were around when the universe was still young, helping them understand how galaxies form. It found protoplanetary disks ( 原行星盘 ), clumps of gas and dust around young stars that likely function as birthing grounds for new planets. It discovered that gamma-ray bursts -- strange, incredibly powerful explosions of energy -- occur in far-distant galaxies when massive stars collapse. And these are only a handful of its many contributions to astronomy. The sheer amount of astronomy based on Hubble observations has also helped make it one of history's most important observatories. More than 10,000 scientific articles have been published based on Hubble data. Why a Space Telescope? E The Hubble Space Telescope is the direct solution to a problem that telescopes have faced since the very earliest days of their invention: the atmosphere. The quandary ( 困惑 ) is twofold: Shifting air pockets in Earth's atmosphere distort the view of telescopes on the ground, no matter how large or scientifically advanced those telescopes are. This "atmospheric distortion" is the reason that the stars seem to twinkle when you look up at the sky. The most effective way to avoid the problems of the atmosphere is to place your telescope beyond it. Or, in Hubble's case, 353 miles (569 km) above the suce of Earth. How It Works F Every 97 minutes, Hubble completes a spin around Earth, moving at the speed of about five miles per second (8 km per second) -- fast enough to travel across the United States in about 10 minutes. As it travels, Hubble's mirror captures light and directs it into its several science instruments. Once the mirror captures the light, Hubble's science instruments work together or individually to provide the observation. Each instrument is designed to examine the universe in a different way. All of Hubble's functions are powered by sunlight. Hubble sports solar arrays that convert sunlight directly into electricity. Some of that electricity is stored in batteries that keep the telescope running when it's in Earth's shadow, blocked from the Sun's rays. First Thoughts G The idea for the space telescope arose in 1923, when German scientist Hermann Oberth, one of the founders of rocketry, suggested blasting a telescope into space aboard a rocket. In 1946, Lyman Spitzer Jr., an American astrophysicist, wrote a paper proposing a space observatory. He would spend the next 50 years working to make the space telescope a reality. The Space Shuttle would be used to put the telescope in orbit and either return it to Earth for repairs and replacement instruments, or service it in space. Work Begins H Shortly after Congress approved funding for the telescope, proposals for science instruments began to pour in. Five winners were chosen. In 1981, the Space Telescope Science Institute was established in Baltimore, Md., to evaluate proposals for telescope time and manage the science program. The space telescope was named the Hubble Space Telescope, after American astronomer Edwin Hubble, who showed that the fuzzy ( 模糊的 ) patches of light in the night sky were actually other galaxies, far distant from our own, and went on to prove that the universe was expanding. I After some delays, Hubble’s launch was scheduled for October 1986. But on January 28, 1986, the Space Shuttle ( 航天飞机 ) Challenger exploded just over a minute into its flight. Shuttle flights ceased for two years. On April 24, 1990, Hubble finally launched into orbit aboard the Space Shuttle Discovery. We Have a Problem J Almost immediately after Hubble went into orbit, it became clear that something was wrong. While the pictures were clearer than those of ground-based telescopes, they weren't the pristine ( 清新的 ) images promised. They were blurry. Hubble's primary mirror, polished so carefully and lovingly over the course of a full year, had a flaw called "spherical aberration ( 球面像差 )." It was just slightly the wrong shape, causing the light that bounced off the center of the mirror to focus in a different place than the light bouncing off the edge. K Fortunately, scientists and engineers were dealing with a well-understood optical problem -- although in a wholly unique situation. And they had a solution. A series of small mirrors could be used to intercept ( 拦截 ) the light reflecting off the mirror, correct for the flaw, and bounce the light to the telescope's science instruments. Astronauts and NASA staff spent 11 months training for one of the most complex space missions ever attempted. In addition to the critical nature of the mission, it would be the first test of the telescope's vaunted ability to be serviced and repaired in space. Repair Crew L On December 2, 1993, the Space Shuttle Endeavor carried a crew of seven into orbit for a mission that would involve five days of spacewalks and repairs. They performed a host of tasks, replacing solar panels, fuse plugs, and other hardware. By December 9, they were finished. NASA released the first new images from Hubble's fixed optics on January 13, 1994. The pictures were beautiful; their resolution ( 分辨率 ), excellent. Hubble was transformed into the telescope that had been originally promised. M Hubble would be successfully serviced and repaired several times afterwards. Each time astronauts performed a servicing mission, they also performed routine repair work -- fixing solar panels and thermal blankets, and upgrading equipment. All Good Things O ually, Hubble's time will end. As the years progress, Hubble's components will slowly degrade to the point at which the telescope stops working. When that happens, Hubble will continue to orbit Earth until its orbit decays, allowing it to spiral toward Earth. Though NASA originally hoped to bring Hubble back to Earth for museum display, the telescope's prolonged lifespan has placed it beyond the date for the retirement of the space shuttle program. Hubble was designed specifically to function with the space shuttle, so the replacement vehicle will likely not be able to return it to the ground. A robotic mission is expected to help de-orbit Hubble, guiding its remains through a plunge through the atmosphere and into the ocean. P But Hubble's legacy -- its discoveries, its trailblazing ( 开创性 ) design, its success in showing us the universe in unparalleled detail -- will live on. Scientists will rely on Hubble's revelations for years as they continue in their quest to understand the cosmos -- a quest that has attained clarity, focus, and triumph through Hubble's rich existence. 1,284 words Comprehension Exercise Each of the following statements contains information given in one of the sections of the passage above. Identify the section from which the information is derived. You may choose a section more than once. Answer the questions by marking the corresponding letter in the blank. _________ 1. Solar arrays provide the electricity that Hubble needs to operate. _________ 2. After Hubble was launched into space, its main mirror was found to have a flaw, compromising the telescope's capabilities. _________ 3. After its flawed optics was fixed, the images that Hubble transmitted showed that it now was able to do the job it was designed to do. _________ 4. Hubble at the end of its lifetime will be enabled to de-orbit and be guided back to earth by a robotic mission. _________ 5. Astronomers using Hubble data have published numerous scientific papers, it one of the most productive scientific instruments ever built. _________ 6. The seven astronauts selected to service Hubble practiced for nearly a year. _________ 7. Hubble is the first major optical telescope to be placed in space, above the distortion of the atmosphere. _________ 8. The disastrous space shuttle accident grounded the space shuttle fleet, forcing the launch of Hubble to be postponed for a couple of years. _________ 9. The Hubble Space Telescope has enabled scientists to sort through and evaluate the many existing theories about the universe and also to propose new ones, thus pointing the way for future research. _________ 10. The Hubble Space Telescope has made many contributions to astronomy, one of which was helping to examine the way galaxies evolve over time.