Учебное пособие Астрономия. Космическая техника и технологии Алматы, 2012 удк 802. 0 52 629. 7 (0758) ббк 81. Англ. 923
 Скачать 1.02 Mb.
|
|
Fossil fuels like coal, oil or gas produce carbon dioxide which leads to the greenhouse effect. This gas makes the atmosphere denser and it traps the heat. CFCs that come from air conditioning, spray cans or burning plastic get into the atmosphere and endanger the ozone layer. Sulfur dioxide and nitrogen oxide are emitted into the atmosphere by industries and cars. These gases can combine with water in the air and produce what is called acid rain. It pollutes lakes and damages buildings and other structures. Answer the questions: 1) What keeps the atmosphere near the surface of the earth? 2) How does the atmosphere protect us? 3) How can the atmosphere change the skies? 4) What is the lower part of the atmosphere made up of? 5) What kind of gases do people create? 6) Why don’t we collapse under the weight of the atmosphere? 7) How far into the sky does the troposphere reach? 8) How do temperatures change in the troposphere? 9) What is the jet stream? 10) What do people have to wear when they climb high mountains? Why? 11) Why do temperatures change in the stratosphere? 12) What would happen without the ozone layer? 11) How far into space does the thermosphere reach? What can we find there? 12) How does gravity change the farther into space you get? 13) How can a volcanic eruption change our atmosphere? Match the words with the definitions:
True or False?T F 1 Without the ozone layer dangerous sunlight would reach the earth’s surface. 2 77 % of the earth’s atmosphere is made up of oxygen. 3 The weight of the atmosphere is the same everywhere. 4 Methane rises into the atmosphere from plants and animals. 5 The atmosphere is kept near the earth because of gravity. 6 The troposphere is bigger near the poles. 7 In the troposphere winds get stronger when you move higher up. 8 Temperatures go down in all parts of the atmosphere. 9 The stratosphere extends to about 80 km above the earth’s surface 10 CFCs come from the sun and endanger our atmosphere 11 Fossil fuels produce carbon dioxide. 12 Acid rain has poisonous gases like sulphur and nitrogen in it. 13 When a volcano erupts sunlight can be blocked out for many years. 14 Rockets can only travel up to the stratosphere. 15 In higher parts of the atmosphere you can find helium and hydrogen. 16 All of the gases in the atmosphere are produced by people. Match a part from A, B and C to form complete sentences:
Listening “Why does Earth rotate?” We are going to listen to New Millennium Program. Welcome to Space Place Musings, where an expert answers questions from our Space Place museum partners across the nation. Our expert is Dr. Marc Rayman, a scientist at the Jet Propulsion Laboratory. Complete the sentences with numbers:
1) Earth's graceful ___ hour rotation rate is one of the traits that make our world so friendly to life, allowing most parts of our planet to stay a nice, comfortable temperature as they are bathed in sunlight during the day and darkness at night. 2) While the rotation may seem slow, Earth is so big that it’s turning at more than ___ miles per hour at the equator. 3) Tiny Mercury, sizzling close to the Sun, takes ___ Earth days to turn around just once. 4) Venus, the second planet, rotates once every ___ Earth days, and in a direction opposite its orbit around the Sun. 5) One hundred years from now, a day will be about ___ milliseconds longer than today. 6) Scientists estimate that a day in the life of early Earth could have been only about ___ hours long. True or False: Decide whether the following statements are true or false by referring to the information in the text. Then make the necessary changes so that the false statements, become true. 1) Each planet in the solar system has the same rotation rate. 2) Almost ten billion years ago, our solar system began as a vast cloud of dust and gas. 3) The cloud began to collapse, flattening into a giant disk that rotated faster and faster as its gravity made it smaller. 4) Scientists believe that a large object, perhaps the size of Mars, hit our young planet, knocking out some chunks of material that eventually collected and became our Moon. This collision may have set Earth spinning faster. 5) As Earth rotates, the Sun's gravity causes the oceans to seem to rise and fall. 6) Throughout history, inventors have worked to develop more and more accurate speed keeping technologies. Speaking Our atmosphere is in danger. It is getting warmer and the ozone layer is being destroyed. What can we do about it? How can we deal with this problem? Unit 8 Telescopes Text 8A Telescope  Based on written records, the invention of the telescope is credited to Hans Lippershey of the Netherlands. Galileo is the first person to use a telescope to look at astronomical objects and record his observations. Galileo built about 30 telescopes but used only 10 to observe the sky. Through his careful observations and dedication, Galileo found support for the Copernican view of the solar system. A telescope collects light from a distant object and focuses it to form an image of the object. When the image is recorded, an observation is made. Originally, the only way to record the image was by hand — astronomers would make a drawing of what they saw through their telescopes. In the 1800’s, photography was invented and astronomers experimented with making photographs through their telescopes. In the early 20th century, astronomers started specifically designing and building telescopes to record the image on photographic plates. The 1980’s saw the invention of charge-coupled devices (CCDs) that allow the image to be recorded digitally. By the end of the 20th century, all research telescopes would use CCDs to make observations. The factors used to determine the quality of a telescope are its ability to gather light, its resolution, its magnification, and the quality of its instruments. Of these, the magnification is the least important for research telescopes. The light-gathering power is a measure of how much light the telescope captures and is a function of the diameter of the primary mirror or lens. The bigger the lens or mirror, the more light the telescope can gather. Resolution is the ability to see detail. A telescope with high resolution can separate two closely spaced objects, whereas a telescope with low resolution will reveal a single object that may be misshaped. Using a different eyepiece can change the magnification of today’s backyard telescopes. As the magnification increases, the telescope focuses on increasingly smaller parts of the sky, reducing the field of view of the telescope. Research telescopes don’t have eyepieces, so they can’t change the magnification and therefore have a fixed field of view for the telescope. Researchers are more interested in the instruments that are used to record and analyze the light. A large telescope with high resolution and quality instruments is desirable for research. Galileo mounted his telescope to minimize the shaking that results from holding the telescope. As technology progressed and telescope tubes became longer, mounting was necessary to support the weight of the telescope. The invention of photography and its application to telescopes made mounting more important. Radio telescopes need to be big for two reasons. One reason is that there isn’t much radio radiation reaching Earth, so big reflectors will capture more light. The second reason is the large wavelength of radio waves. To resolve closely spaced sources, the radio dish needs to be very large. One alternative to building very large radio telescopes is to build arrays of telescopes. Solar telescopes are specialized to observe the hot, bright Sun, the nearest star to Earth. The heat and brightness of the Sun make it difficult to use equipment that was designed to look at dim sources of light like distant stars and nebulae. The effects of heating tend to change the shape of the mirrors and cause the air to move, which blurs the image Telescopes are put into space to get above the distorting effects of Earth’s atmosphere. For visible light, pockets of air in the atmosphere act like tiny lenses, bending the light from celestial objects in random, unpredictable directions. By placing a visible-light telescope above the atmosphere, these distortions are not encountered. Also, the atmosphere absorbs most other wavelengths of light. Placing a telescope in space is the only way to view celestial objects in those wavelengths. Answer the questions: 1) Who invented the telescope? 2) How does a telescope work? 3) By what qualities is a telescope judged? 4) Why are telescopes mounted? 5) Why do radio telescopes need to be so big? 6) Why are solar telescopes different from other telescopes? 7) Why are telescopes put into space? Text 8B Hubble The 32,000–word novella The Time Machine by H.G. Wells, published in 1895, is generally credited with popularizing the idea of time travel by means of a time machine, a vehicle which takes the occupant backward or forward in time. Dozens of sequels and adaptations over the years have further promoted the notion. Indeed, Albert Einstein’s Theory of Special Relativity lays the foundation for the possibility of time travel. So far, no one has demonstrated the ability to travel in time. However, time machines have been constructed, and they do allow glimpses into the past. The most efficacious time machine currently in existence is the Hubble Telescope, named after the American astronomer Edwin P. Hubble. Its capability to locate distant astronomical targets and lock in on them, permitting their faint light to aggregate on its detectors, allows it to peer far into the past. Light travels 186,000 miles per second. The Hubble Telescope has looked back in time at 10,000 galaxies whose light left them billions of years ago. Therefore, utilizing the telescope as time machine, astronomers are able to contemplate galaxies as they were eons ago. Although the telescope was launched into space in 1990, its inception was almost a half–century earlier as astronomer Lyman Spitzer, Jr. mulled over the possibility of a large space telescope in a 1946 report, “Astronomical Advantages of an Extra–Terrestrial Observatory.” Because the earth is bathed in its constantly churning atmosphere, earth–based telescopes cannot penetrate deep space; the atmosphere distorts the view. Telescopes were constructed on mountains, but there was still no way to wholly escape the effects of the layers of gases enveloping the earth. During the 1960s, the Space Race between the then–Soviet Union and the United States was accelerating. The National Aeronautics and Space Administration (NASA) was established. Funds for space endeavors were abundant, and plans for a large space telescope, by then designated the LST, were underway. The designs called for a 2.4–meter primary telescope mirror which could be transported into space by one of NASA’s rockets. According to National Geographic’s Imaging Space and Time, the resolving power of the deep space telescope would be “equivalent to being able to distinguish the left and right headlights of a car in California seen from New York, or features less than 1/30,000th the size of the full moon. This was at least a tenfold increase over the atmospheric limit.” One of the primary challenges involved in successfully transporting the telescope into space was protecting the mirror from the jarring vibrations that occur during launch. It was crucial that the mirror be able to withstand the shuttle’s vicissitudes as well as the volatile atmospheric conditions found in space. If not, the precise shape of the mirror could be compromised, and its imaging capability significantly weakened. After the telescope had been launched, astronomers subsequently realized that the primary mirror had not been ground correctly. A lens in the test instrument was about one millimeter askew, which is large by optical standards. In 1993, space–walking astronauts installed corrective lenses which improved the eyesight of the Hubble. In 2009, the corrective lenses themselves were replaced with a supersensitive spectrograph with built–in corrective lenses. The new spectrograph is expected to provide insight into the origins of stars and galaxies. The successor to Hubble, the James Webb Space Telescope, is expected to be launched in 2014. It will observe only in infrared, so it will complement the Hubble Telescope, which observes in the visible and ultraviolet light ranges. Hubble currently has the capability to view galaxies that were formed 13.7 billion years ago, long before humans existed, in an area called the Hubble Ultra Deep Field. Astronomers aspire to see beyond the Hubble Ultra Deep Field to a time that is devoid of galaxies, a time before galaxies had formed. If H.G. Wells was onto something in his novella, that time may be close at hand. As one of the characters in the popular work asked, “If Time is really only a fourth dimension of Space, why is it, and why has it always been, regarded as something different? And why cannot we move in Time as we move about in the other dimensions of Space?” Less than a decade after Wells’ novella, Einstein’s Special Theory Relativity seemed to concur with Wells’ character by proposing that traveling through space at the speed of light would alter time by causing it to dilate, raising the possibility of not merely glimpsing the past, but perhaps traveling to it. |