Listen to the passage again and check out the script.
★Listen to part of a talk in a Space Science class
One of the main causes of the environment pollution is the crisis of the commons. The crisis of the commons is the problem results when the part of environment is not own by anyone. Take a park, one reason that the park grounds are frequently more litter than people backyard is no owns them. People who throw the paper trash away in the park can walk away as nothing happened because the park is not theirs. A new extremely large crisis of commons that the astronomers are becoming increasingly aware of is the pollution in outer space. Since nobody own space, nobody has truly personal interesting to clean it up. The problem of space pollution is more acute than that in the park too because the inability space to clean itself up. The paper bank in the park will eventually disintegrate into its basic element but junk in space is unable to be broken down naturally by water and oxygen and so it stays there. Old satellites orbiting the earth out of control of space agency the launch them are the main sources of pollution in space. Collisions within the old satellites result them breaking up into smaller pieces. And this multiplies the amount of free flowing litter. A piece of matter only decides a mobile impact against the large space satellite has the same force as the safe dropped off the roof of the skyscraper. One astronomer estimates that large space satellites orbiting the earth now stands a ten percent chance been hit by discard in space degree.
Correct answers :BABD
