It took 100 years, 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 100 years 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 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 director of the LIGO observatory at Caltech. "We have detected gravitational waves. We did it!" 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 they contract and expand the planet as the waves go 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 the other in Washington state. For years, scientists have been watching two black holes in another faraway galaxy. 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 l. 3 billion years later. They are the same waves that the scientists announced this past week. So, what does this discovery mean? Our understanding of the heavens changed dramatically. What are gravitational waves about?
About the workings of the universe. About how black holes form. About how the universe began. About how the ripples form on the surface of water.
Question: It took 100 years, 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 100 years 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 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 director of the LIGO observatory at Caltech. "We have detected gravitational waves. We did it!" 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 they contract and expand the planet as the waves go 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 the other in Washington state. For years, scientists have been watching two black holes in another faraway galaxy. 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 l. 3 billion years later. They are the same waves that the scientists announced this past week. So, what does this discovery mean? Our understanding of the heavens changed dramatically. What are gravitational waves about?
A. About the workings of the universe.
B. About how black holes form.
C. About how the universe began.
D. About how the ripples form on the surface of water.
Answer: