signalling [signsliol interior [infisrie]

missile [misail] projectile [prodsiktail]

effort Iefst] allies [aelaiz] adequate [aedikwit]

ДОПОЛНИТЕЛЬНЫЕ ТЕКСТЫ ДЛЯ ПЕРЕВОДА

1, MEASURING STAR DISTANCES (Для перевода без словаря)

Measuring star distances was first effected» as early as in 1835. The principle of the method is simple enough; it is essentially the same as that employed in measuring distances on the Earths surface. The object which is under study and whose distance is required is observed from two ends of a base-line of known length, the observations giving the angle between the two ends of the base-line. It appears that the difficulty of measuring star distances arises from the fact that the longest base-line available* for the purpose is very short compared with the distances of the stars involved. By making the observations when the Earth is at the two ends of its orbit, a base-line of about 186,000,000 miles fs obtained. No longer base-line is possible.

It is convenient to express star distances in terms of the time that light takes to travel. Light travels with a speed of 186,000 miles a second, so that in the course of a year it will travel a distance nearly six million million miles. Thus, instead of saying that the nearest star is nearly 25 million million miles away from us, we may say that it is about four light-years away.

This way of expressing the distance is very interesting because it reminds* us, that we see the star not where it is at the moment, but where it was at least four years ago.

There is a limit to the distances that can be determined by direct measurement. For distances greater than about 500 light-years, the results become rather uncertain. The methods to be used are quite different. Such a method has been suggested, and the evidence that has been obtained within the last two decades about the structure of the universe has been gained, in a very large measure, by the application of this method. It is based on the special properties of a particular class of stars. These stars do not shine with a steady constant light, there are fluctuations in their brightness. These fluctuations have been found to be associated with regular pulsations of the whole star. The time required for a single pulsation to be completed, though it is constant for any one star, ranges for different stars from several hours to about 30 days. There is a definite relationship between the period of pulsation and the candle-power of the star, so that if the period is known, the candle-power can be found out.

There is no difficulty in finding the time taken by a pulsating star in going through one complete cycle of light variation. It is doubtless that the longer the period of pulsation, the greater is the candle-power of the star. Thus, for example, if one pulsation is completed in two days, the candle-power is 260 times that of the Sun; if it is completed in ten days, the corresponding candle-power is 1,700 times that of the Sun.

It will be noticed that the candle-power In each of these examples is far greater than that of the Sun. The pulsating stars are all very bright. Their brightness makes it possible to see them far away across the space. It is this fact that makes them so useful in the exploration of space to great distances.

Having discussed the general principles that underlie the determination of great distances, we can summarize the information that has been derived about the universe in which we find ourselves.

* effect - осуществлять

2 available - доступный, имеющийся в наличии express - выражать

* remind -напоминать

* shine - светить

candle-power - яркость свечения

2. BODES LAW

(Для перевода без словаря)

In 1772 Johann Elert Bode discovered a very convenient way of obtaining the approximate distances of the planets from the Sun without going through all the mathematics required by either Keplers or Newtons laws. This relationship is known as Bodes law, but there seems to be no reason for its existence. It cannot be explained by any known theory. It may have no physical meaning; nevertheless it is a remarkable way of remembering planetary distances.

If we start with the figures 0, 3, 6, 12, 24 and so on *, doubling each time after the zero figure, then adding 4 to each one, and finally dividing by 10, we obtain the distances from the planets to the Sun in astronomical units.

The following table gives a comparison between the distances determined by Bodes law and their actual value.

* and so on ~ и так далее

* double-удваивать

add- добавлять, прибавлять

MEAN » DISTANCE FROM THE SUN

* mean - средний.

** a. u. (astronomical unit) -астрономическая единица.

3, CHEMISTRY AND THE ATOMIC THEORY

(Для перевода со словарем)

Chemistry has long assumed that material substances are composed of atoms; and the actual investigation of the properties of material substances shows them to be divided into two classes: compound substances, which can be reduced to simpler ones by appropriate methods; and the simple substances themselves - the chemical elements - which resist any attempt at such reduction.

The study of the quantitative laws, in accordance with which the simple substances combine to form compounds, led chemists during the last century to adopt the following hypothesis:

"A simple substance is supposed to be formed of small particles, all identical with each Gther, called the atoms of this element; compounds, on the other hand, are supposed to be formed of mo ecules resulting from the combination of a number of atoms tonstituting the simple substances". According to this hypothesis, therefore, a composite substance is broken up by reducing it to the elements of which it is composed which means that its molecules are disintegrated and the atoms which they contain set free. All material substances are regarded to be constructed from 104 different kinds of atoms.

The atomic theory not only succeeded in introducing order into chemistry: it also extended into the domain of physics. For if material substances are composed of molecules and atoms, then their physical, properties must be capable of explanation in terms of their atomic structure. The properties of the various gases, for example, must be explicable on the assumption that a given gas consists of an immense number of mo ecules or atoms in rapid motion; the pressure of a gas on the wall of the