5.Writing

Write the translation of the following text or render its content in English.

КРИВОЕ ЗЕРКАЛО ЗЕМЛИ

Венера — ближайшая к Земле планета Солнечной системы. Основные параметры Венеры делают ее едва ли не близнецом нашей планеты: радиус — 0,95; объем — 0,9; масса — 0,8; средняя плотность — 0,95; сила тяжести — 0,9 от всех аналогичных зем­ных величин. До начала эры космических полетов не были изве­стны ни температура поверхности Венеры, ни давление, ни со­став атмосферы, ни особенности рельефа. Диапазон гипотез о «венерианской действительности» был весьма широк, но все они имели одну общую черту — так или иначе ученые рассчитывали встретить на планете условия, не слишком сильно отличающиеся от земных.

Атмосфера Венеры содержит 97 % углекислого газа (С0₂), 3 % азота, и 1 % приходится на пары воды и некоторые другие газы. Та­кой состав резко отличается от преимущественно азотной атмос­феры Земли. Температура атмосферы у поверхности Венеры чрез­вычайно высока — около 470 °С. Причем ее перепады от дня к ночи составляют не более Г, а от экватора к полюсам — не более 12°. Но вот с высотой температура заметно понижается: на верши­нах наиболее высоких гор она почти на 100° ниже, чем в низмен­ностях. Атмосферное давление на поверхности Венеры, почти в 100 раз превышающее земное, можно сравнить с давлением воды в земных океанах на глубине около 1 км.

Плотность атмосферы у поверхности Венеры примерно в 50 раз больше, чем тот же земной показатель. 40 % массы венерианской атмосферы находится в пределах 10 км от поверхности планеты. Можно сказать, что воздух там в определенной степени вязкий и движение в такой плотной газовой среде должно чем-то напоми­нать перемещение в воде.

Как на планете, подобной Земле, сложились совершенно иные климатические условия? Под влиянием каких процессов возникла венерианская атмосфера? К ответу на эти сложнейшие вопросы, важные даже не столько для понимания эволюции самой Венеры, сколько для прогноза будущего самой Земли, ученые сегодня смогли лишь приблизиться.

6. Speaking

   1. Retell the following texts in English.

DESERT LANDSCAPES

Most dictionaries define a desert as “a wilderness,” “a barren place”, or “a place without people”. But these definitions could apply equally well to polar areas or to many mountain regions. What, then, makes a desert distinctive among physical settings?

Geographic definitions. When geographers use the word desert, they have something special in mind. A geographer’s desert may be crowded with people. For example, Cairo and Alexandria, Egypt, both lie in a desert, yet millions of people live in these two cities. So “wilderness,” “barren,” and “place without people” really do not provide a useful geographic definition of desert.

To the geographer, lack of water is the fundamental factor that defines a desert. Deserts have little surface water, limited groundwater, and unreliable rainfall.

Unreliable precipitation. Annual average precipitation figures for deserts often are almost meaningless. Although statistics may say that a desert area receives 12.5 cm of rain a year, the figure does not mean that amount of rain falls every year. This is because averages are calculated by adding all the precipitation received over a period of years and then dividing the total by the number of years. So in one year, for example, a place may receive 25 cm of rain. The next year it may receive no rain at all. The yearly average for those two years would be 12.5 cm. Such an average number is misleading because all the precipitation for a given year may fall in one or two heavy showers. Such heavy rains usually pelt the hard, dry earth and run off rather than penetrating the surface.

Colors of the desert. Two colors symbolize life and death in many desert areas. The primary desert color — brown — illustrates the lack of water. Often this color stretches as far as the eye can see. And even though the brown desert may burst into bloom after a rain, the colorful outburst is short-lived and brown soon returns.

The other desert color — green — identifies the few arable areas. Here life-giving water is available from rivers such as the Nile or from underground reserves. People can be found, often in large numbers as in Cairo, living on these green ribbons in the world’s deserts.

The line between green and brown is often sharp in desert regions. The rich green of an irrigated oasis or river valley suddenly ends. Beyond is the vast, dry emptiness of brown terrain.

DESERTIFICATION

To understand the events that have occurred in recent years along the southern edges of the Sahara, you must know two key terms — Sahel and desertification.

The Sahel. Located south of the Sahara, the semi-arid Sahel covers large parts of Burkina Faso, Chad, Gambia, Guinea-Bissau, Mali, Mauritania, Niger, and Senegal. Today the loss of valuable soil threatens to transform the entire Sahel into desert.

Desertification. A combination of human activities and continued drought cause desertification — the spread of desert conditions. Desertification began to engulf the Sahel in 1968. No rains came and though drought persisted, nomadic herders continued to graze their livestock. Pastures became increasingly eroded. Soon vast areas were so desperately overgrazed that no pastures remained. .

In addition to overgrazing the land, the nomads cut the few trees and shrubs for firewood. This deforestation leaves the soil bare and open to devastating winds that sweep the soil away. But wood provides 80 to 90 per cent of the region’s energy and cutting the trees is a necessity. As a result, deforestation is extremely rapid. Each year sahelian residents strip trees from 2,600 to 3,900 square kilometers of woodland and reforest only one- tenth of that. And always the winds come to sweep the soil away.

Although the nations of the region recognize the dangers of deforestation and have established tree-planting campaigns, the programs have had limited success. The people of the Sahel think of trees in terms of firewood, not as protection against the relentless march of the desert.

Effects of desertification. Desertification has had disastrous effects on the region. Hundreds of thousands of people and millions of animals have died of starvation. And as the Sahara relentlessly gobbles up the Sahel at the rate of 6 kilometers per year, more and more flee to the region’s impoverished cities. Having lost their herds — their traditional source of livelihood — nomads now crowd into wooden and tin shacks and depend on assistance from others to survive. Nouakchott, Mauritania, for example, has absorbed more than 500,000 refugees since the drought began. Meanwhile, a reddish-orange cloud of sand and soil blocks the sun from view as the Sahara continues to expand.