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18£®It took 100years£¬but finally£¬scientists proved Albert Einstein's theory that gravitational waves exist£®The waves were predicted as part of Einstein's General Theory of Relativity nearly 100years ago£®It was the theory of the physics behind the workings of our world and the universe£®The idea was that the waves are like ripples£¨Á°äô£©in space£¬caused by some of the violent and energetic processes in the Universe£®For example£¬two black holes crashing into each other£®
Now a group of scientists£¬including ones from CalTech£¬MIT and the LIGO Scientific Collaboration finally found the gravitational waves£®
David Reitze is the executive£¨ÓÐÖ´ÐÐȨµÄ£©director of the LIGO observatory£¨ÌìÎĄ̈£© at CalTech£®"We have detected gravitational waves£®We did it!"Reitze spoke with others at a press conference in Washington£¬DC this past week£®The scientists announced they were able to see ripples in the fabric£¨Ö¯Îof space time£®
What are these gravitational waves£¿Well£¬imagine throwing a rock into a pond£®When the rock hits the flat surface of the water£¬it creates ripples or waves£®Space time is like the surface of the water£®So that means gravitational waves are like the ripples moving out from where the rock hits the water£®
It might be hard to understand£¬but those gravitational waves expand and contract space and time as they move through space£®And when they get to the Earth£¬the waves pass through£¬and contract and expand the planet as the wave goes by£®
It was Einstein who said these gravitational waves should be observable£®But these are not huge waves£®They are very£¬very small£¬which is why it took so long to find them£®You cannot see them with your eyes£®They are smaller than the size of an atom£®
How did the scientists find them£¿They used a giant scientific tool called LIGO-which stands for the Laser Interferometer Gravitational-Wave Observatory£®The billion-dollar LIGO project is two L-shaped observatories£®One is in Louisiana and one in Washington state£®Their job was to watch for these gravitational waves£®They have been looking on and off since 2002£®
For years£¬scientists have been watching two black holes in another galaxy£¨ÒøºÓ£©faraway£®The two were spinning around each other£¬moving closer and closer together£®When they finally crashed into each other£¬it was with such power and force£¬that gravitational waves rang throughout the universe£¬like a giant bell£®Those waves£¬traveling at the speed of light£¬finally reached the Earth£¬some 1.3billion years later£®They are the same waves that the scientists announced this past week£®Each of the black holes was thought to be 29to 36times the mass of our sun£®
So£¬what does this discovery mean£¿
Abhay Ashtekar is a Penn State physicist£¬who was not on the discovery team£®He said£º"Our understanding of the heavens changed dramatically£®"
24£®According to the text£¬which of the following statements is true£¿C
A£®Gravitational waves have been existing for 100years£®
B£®Albert Einstein proved the existence of gravitational waves£®
C£®Gravitational waves travel as fast as light£®
D£®Albert Einstein predicted the existence of black holes£®
25£®What can be inferred from the text£¿A
A£®The LIGO project costs a lot of money£®
B£®The LIGO project is directed by Abhay Ashtekar£®
C£®The LIGO has been watching for gravitational waves continuously£®
D£®The LIGO observatory is intended to detect black holes£®
26£®What is the text mainly about£¿B
A£®Einstein's General Theory of Relativity£®
B£®The detection of gravitational waves£®
C£®David Reitze's LIGO project£®
D£®The crash of two black holes£®
27£®The underlined word"contract"probably meansB£®
A£®make a legal agreement with someone
B£®become shorter or narrower or smaller
C£®catch or develop an illness
D£®communicate with someone£®
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25Ìâ´ð°¸£ºA¿¼²éϸ½ÚÍÆÀí£¬¸ù¾ÝÎÄÕµ¹ÊýµÚÈý¶ÎµÄThe billion-dollar LIGO project is two L-shaped observatories¡"Õâ¸ö»¨ÁËÒ»ÒÚÃÀÔªµÄ¹¤³ÌÊÇÁ½¸öLÐ͵ÄÌìÎĄ̈¡"¿ÉÖª±¾Ìâ´ð°¸ÎªAÑ¡Ï
26Ìâ´ð°¸£ºB¿¼²éϸÖ÷Ö¼¸ÅÀ¨£¬ÎÄÕÂÏêϸ½éÉÜÁËÒýÁ¦²¨µÄ²úÉú£¬ÒýÁ¦²¨·¢ÏÖµÄÒâÒåºÍÒýÁ¦²¨µÄÑ°ÕÒ¹ý³Ì£»¹Ê±¾Ìâ´ð°¸ÎªBÑ¡Ï
27Ìâ´ð°¸£ºB¿¼²éϸ½ÚÍÆÀí£¬¸ù¾ÝÎÄÕµÚÁù¶ÎµÄbut those gravitational waves expand and contract space and time as they move through space£®"µ«Êǵ±ÕâЩÒýÁ¦²¨´©¹ýÌ«¿ÕʱËüÃǻᲨÀ©ÕŲ¢ÇÒ___¿Õ¼äºÍʱ¼ä£®"¿ÉÖªcontractÒ»´ÊµÄº¬ÒåΪ"ʹijÎï±ä¶Ì¡¢±äС»ò±äÕ"£¬¹Ê±¾Ìâ´ð°¸ÎªBÑ¡Ï
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