Lesson 8 our earth read the text, translate and retell

LESSON 8
OUR EARTH

1. 
   Read the text, translate and retell.
   

The earth is a huge, slightly lopsided ball of rock, so enormous that we can scarcelyimagine how heavy it is; it weighs about 6,6·10²⁰ tons. It’s diameter through the equator is 7,926, 68 miles, but from pole to pole the diameter is 7,899,98 miles, or 26,7 miles less. In spite of this very small flattening, and an even smaller bulge in the southern hemisphere, the earth is still nearly a perfect sphere. When geologists talk of the earth as a ball of rock, they do not mean it is solidly made up of the stones you see on a rocky beach.

Scientists actually know very little about the rocks deep inside the earth, and even the definition of a rock itself may seem vague and complicated. It is easy to define chemical elements and the minerals they form, but it is not easy to define the rocks of which the earth is made of.
All life is as we know, spread out in a thin layer on, or close to the surface of the rocky earth. Some plants and animals make their homes two or three miles above the sea level. Others can survive an equal depth below the surface of the sea. But it is within this thin six-mile layer, that over 99, 99 percent of all plants and animals live, grow, and die. The story of where rocks came from is closely related to the origin of the earth, and this mystery is yet to be unraveled. The best guess is that the earth and the entiresolar system have been in existence for a little over four billion years. Astronomers get a fairly good idea of the chemical composition of the universe by studying the light from the stars and the sun. But as soon as scientists have to deal with the smaller, colder bodies like the planets and satellites, information is more difficult to obtain.
Our direct knowledge of rocks is limited very much to the crust of our earth. The deepest hole that man has ever been able to dig in it is an oil well that goes more than 9 km deep. This is only about five miles down, a mere pinprick into the crust.