Man and the Universe
(From the history of astronomy)
It is thought that man studied the stars, the planets, the Moon and the Sun in prehistoric times and it is believed that ancient monuments such as the Pyramids were built upon astronomical knowledge.
What prehistoric ideas of heavenly bodies may have been we do not know, except where some written evidence has come down to us to decipher.
Probably the first big step was the idea that the earth was a sphere. That idea, although, it was wrong, made it possible to assert that the heavens revolved around the earth.
The Greeks made great advances in geometry and mathematics from the observations they could make with the naked eye and simple instruments for measurement. They measured rather accurately the diameter of the earth and the distance to the Moon, but they could not measure greater distances such as the distance to the Sun. They developed the geocentric theory of the Universe according to which the Earth was a stationary body around which everything revolved. This was the Ptolemaic system.
Even in the Middle Ages astronomers thought the system was correct, and, though there were philosophers who considered it wrong, they could give no proof tosupport their ideas.
It was Copernicus who developed a new theory of a heliocentric solar system. That was a much simpler idea and explained many of' the errors discovered by increasing accuracy of measurements, especially of the movement of the other planets.
Kepler perfected the Copernican theory and Newton's law of gravitation, explained it so clearly that even reactionary scientists had to accept it. With the help of the new astronomic instrument, the telescope, it became clear that the geocentric theory was entirely wrong. Even so, it was only in 1837 when Bessel measured the actual distance to the nearest star (or so he thought) that scientists received the final proof that the heliocentric theorywas correct.
This required powerful telescopes and very accurate measurements down to a small fraction of a second of arc (1/3600 part of a degree of an angle). Bigger telescopes with photography helped man to look deeper intospace. Scientists could
now see beyond our solar system, beyond ourGalaxy. They foundthere were other galaxies, so far away that the light from them travelled many million years before itreached our planet. With the help of the spectroscope itbecame possible to see those tiny beams of light, to learn the composition of stars, their temperature andeven the speed at which they were travelling away
from us or towards us.
Einstein's theory of relativity added information to Newton's gravitation law.
The new knowledge of sub-atomic physics and thermo-nuclear reactions gave us theoretical ideas about the life history of stars, and the conditions and reactions that may be found on them.
Then came radio astronomy which helped to explore invisible objects beyond the reach of any telescope.
And now we are living in the Cosmic era. Rockets have been sent to the Moon, round the Moon, giving us views man has never seen before.
1. somewrittenevidencehascomedowntoustodecipher– некоторые еще не расшифрованные письменные свидетельства дошли до нас
2.made it possible to assert – давала возможность утверждать
3. with the naked eye – невооруженным глазом
4. Ptolemaic system – геоцентрическая система Птолемея
5. It was Copernicus who developed a new theory of a heliocentric solar system–лишьКоперниксумелобосноватьсвоюновуюгелиоцентрическуюсистему
6. that scientists received the final proof that the heliocentric theory was correct–ученыеполучилиокончательноедоказательствоправильностигелиоцентрическойтеории
8. heavenly – небесный
9. evidence – свидетельство
10. probably – возможно
11. advance – открытие
12. according to smth. – согласно чему-либо
13. stationary – неподвижный
14. the Middle Ages – Средние века
15. consider – считать, учитывать
16. proof – доказательство, свидетельство
17. law – закон
18. scientist – ученый
19. entirely – полностью, всецело
20. tiny beams of light – крошечные пучки света
21. Einstein’s theory of relativity – теория относительности Эйнштейна
22. invisible objects – невидимые объекты
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