RADIO IN ASTRONOMY

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Today the optical telescope is no longer the means of exploration of space. Most of the information we get about other galaxies comes through the radio-telescope. As an astronomical device the radio-telescope is a far more efficient means than any of those used in the last century. The possibilities of radio-astronomy are much greater than those of optical astronomy.

Radio-astronomy gives us not only more and more information of what the universe is like but also provides technical means for its exploration. Without radio the observation of artificial satellites and cosmic ships would be quite impossible.

The development of radio has resulted in the discovery that radio-waves from outer space are continually coming to the Earth. Giant radio-telescopes listen to the voices of the stars so far away that it takes one thousand five hundred million years for their light to reach us. It has been proved that the Sun itself emits radio-waves. Radio-waves from the Sun have recently been put to practical use in an instrument called a radio sextant.

TEXT 11 C

THE STORY OF RADIO

1) Study the text. Try to understand all details. Use a dictionary if necessary:

1. Without understanding the inquiries of pure science, we cannot follow the story of radio. It begins perhaps with Joseph Henry, an American physicist, who discovered in 1842 that electrical discharges were oscillating. A gigantic step forward was taken by James Maxwell, a Scottish physicist and one of the great mathematical geniuses of the 19-th century. By purely mathematical reasoning, Maxwell showed that all electrical and magnetic phenomena could be reduced to stresses and motions in a medium, which he called the ether. Today we know that this “electrical medium” does not exist in reality. Yet the concept of an ether helped greatly, and allowed Maxwell to put forward his theory that the velocity of electric waves in air should be equal to that of light waves, both being the same kind of waves, merely differing in wave length.

2. In 1878, David Hughes, an American physicist, made another important discovery in the pre-history of the radio and its essential components. He found that a loose contact in a circuit containing a battery and a telephone receiver (invented by Bell in 1876) would give rise to sounds in the receiver which corresponded to those that had impinged upon the diaphragm of the mouthpiece.

3. In 1883, George Fitzgerald, an Irish physicist, suggested a method by which electromagnetic waves might be produced by the discharge of a condenser. Next we must turn to Heinrich Hertz, the famous German physicist, who was the first to detect and measure electromagnetic waves, and thereby experimentally confirmed Maxwell’s theory of “ether” waves. In his experiments he showed that these waves were capable of reflection, refraction, polarization, diffraction and interference.

4. A.S. Popov (1859-1906) was in 1895 a lecturer in physics. He set up a receiver in 1895, and read a paper about it at the Meeting of the Russian Physico-Chemical Society on April 25 (May 7, New Style) 1895. He demonstrated the world’s first radio receiver, which he called “an apparatus for the detection and registration of electric oscillations”. By means of this equipment, Popov could register electrical disturbances, including atmospheric ones. In March 1896 he gave a further demonstration before the same society. At that meeting the words “Heinrich Hertz” were transmitted by wireless telegraphy in Morse code and similarly received before a distinguished scientific audience.

5. Marconi invented a system of highly successful wireless telegraphy, and inspired and supervised its application. Such is the story of the many inventors of wireless telegraphy, working with each other’s equipment, adding new ideas and new improvements to them. It was a patient, persistent inquiry into natural laws and it was animated by the love of knowledge.

6. During the first year of its development, radio communication was called “wireless telegraphy and telephone”. This name was too long for convenience and was later changed to “radio” which comes from the well-known Latin word “radius” – a straight line drawn from the center of a circle to a point on its circumference. Wireless transmission was named radio transmission, or simply “radio”.

7. The term “radio” now means the radiation of waves by transmitting stations, their propagation through space, and reception by receiving stations. The radio technique has become closely associated with many other branches of science and engineering and it is now difficult to limit the word “radio” to any simple definition.

2) Say whether the following statements are true or false:

1. H. Hertz was the first to create electromagnetic waves. 2. A.S. Popov could not register atmospheric disturbances. 3. A.S. Popov is the inventor of the radio. 4. The words “Heinrich Hertz” were transmitted by wireless telegraphy in Morse code.

3) Answer the following questions on paragraph 1:

1. Who discovered the oscillation of electrical discharges? 2. Does “the ether” exist in reality? 3. What did the concept of an ether help Maxwell in?

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