Aboutl.3billionyearsagotwomassiveblackholeshiteachotherandformedanewone.Theenergysetfreebythecollision(撞击)createdaripple(波纹)inthespace-timestructureandspreadoutwardingravitationalwaves(引力波).

Question

About l.3 billion years ago two massive black holes hit each other and formed a new one. The energy set free by the collision(撞击) created a ripple(波纹) in the space-time structure and spread outward in gravitational waves(引力波).

    Then on September 14 2015 a group of scientists discovered the waves. On February 11 an announcement came from the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US that for the very first time a gravitational wave was directly observed and recorded.

 "We discovered gravitational waves! We did it!" David Reitze the director of LIGO said in the press conference on February 11. "It's exactly what Einstein's theory of general relativity predicted.”

    Einstein's 1915 theory re-imagined the framework for the universe. According to Einstein the framework for the universe ---- or the space-time structure ---- is not fixed but changed by matter and energy "in a way a heavy sleeper causes a mattress to sag(床垫下凹) producing the effect we call gravity" explains a New York Times article.

"A disturbance in the universe could cause space-time to become larger break into pieces and even move up and down like a mattress shaking when that sleeper rolls over producing ripples of gravity ---- gravitational waves " explains the article.

Compared with the other three forces in the universe (electromagnetism the weak nuclear force and the strong nuclear force) gravity is relatively weak making gravitational waves hard to discover.

    The discovery by LIGO would open a new chapter in astronomy. "Everything else in astronomy is like the eye " Szabolcs Marka a Columbia University professor told The New York Times. "Finally astronomy grew ears. We never had ears before."

32. What is a gravitational wave according to the text?

A. It's a disturbance in the universe.               B. It's the crash of the two black holes.

   C. It's a ripple in the space-time structure.         D. It's an effect caused by energy.

33. What is the main reason for David Reitze’s excitement about the discovery?

   A. It proves Einstein's 1915 theory.                  B. The waves were hard to discover.

   C. The waves changed the universe.                D. It reshapes the space-time structure.

34. What can we learn from the text?

   A. It took LIGO 4 months to confirm the discovery.

   B. The framework for the universe can be changed.

   C. One produces gravity because he sleeps heavily.

   D. There are more than four forces in the universe.

35. What is the last paragraph mainly about?

   A. Astronomy calls for more attention.

   B. Never before has astronomy achieved much.

   C. Astronomy is more about what we can hear in space.

   D. A better understanding of the universe is made possible.

Answer 1

CABD