阅读理解

　　Many people think that the exploration of space began when people first put on spacesuits and went up in rocket ships．But people started exploring space long before anyone could travel there．The first space explorers were the ancient Egyptians and Arabs．They studied the sky and passed along their knowledge to the ancient Greeks．The Greeks put these ideas together with new ideas of their own and created the science of astronomy．Astronomy is the study of the stars．The first important Greek astronomer, or space scientist, was Pythagoras．In 560 BC, when people thought that Earth was flat, Pythagoras thought that it was round．Another important Greek scientist was Aristarchus．In about 360 BC, he taught that Earth and all the other planets revolve, or move in a circle, around the sun．Now, of course, we know that he was right．A little more than five hundred years later, another Greek scientist named Ptolemy wrote a book in which he argued that the planets, the sun and everything else in the heavens revolve around Earth．For more than 1500 years, many people believed that he was right．

　　In 1543, the Polish astronomer Nicolaus Copernicus published a new book．Copernicus said that Earth and all the other planets revolve around the sun．This was an unpopular idea．People were used to believing that Earth was the centre of everything．This idea made them feel special．Powerful religious leaders had even made this part of church law．In 1609, the Italian astronomer Galileo Galilei learned of a new invention called the telescope, which could make distant objects appear closer and larger．Galileo built his own telescope to look at the sky．What he saw convinced him that．Earth revolved the sun．However, it was a long time before people finally decided that he was right．The great English scientist Sir Issac Newton also thought that Earth revolved around the sun．In 1668, Galileo invented a telescope that was better and stronger than the one Galileo had used．It allowed people to see much farther into space．Through the 1700s, 1800s, and 1900s, scientists continued to use telescopes to explore space．They made many discoveries．They discovered the planets Uranus, Neptune and Pluto．They also observed comets．But this was not enough．In May 1926, a scientist from the USA dreamed of using a rocket to reach the moon．He designed a rocket that climbed forty feet into the air．That does not sound like a great distance, but it was farther than any liquid-fueled rocket had gone before．The age of space travel began．