No actual black hole has yet been located or studied, but the concept has…………….
No actual black hole has yet been located or studied, but the concept has provided endless imaginative fodder for science fiction writers and endless theoretical fodder for physicists and astrophysicists.
Black holes are one of the more exotic theoretical manifestations of general relativity. The standard model for the formation of a black hole involves the collapse of a large star. For extremely massive stars that are four to five times the mass of our sun, the exclusion principle—the resistance between the molecular particles within the star as they are compressed—will not be strong enough to offset the gravity generated by the star’s own mass. The star’s increasing density will overwhelm the exclusion principle. What follows is runaway gravitational collapse. With no internal force to stop it, the star will simply continue to collapse in on itself, until it reaches a point of infinite density and zero volume, a phenomenon known as a singularity.
The star now disappears from the perceivable universe, like a cartoon character who jumps into a hole and pulls the hole in after him. What this process leaves behind is a different kind of hole—a profound disturbance in space time, a region where gravity is so intense that nothing, not even light, can escape from it. Any object falling within the boundary of a black hole will be sucked in and will disappear from our universe forever.
What would happen to an object, such as an astronaut, as it vanished into the black hole? Physicists have been amusing themselves with this question for years. Most believe that the astronaut would be destroyed by the intense gravitational forces within the black hole, or would explode in a flash of gamma rays as he or she approached the singularity at the hole’s core. Theoretically, an astronaut who managed to survive the passage would experience some very strange things, including acute time distortion, which would enable him or her to know, in a few brief seconds, the entire future of the universe in all its detail.
1. The word “fodder” is closest in meaning to
A. material
B. stories
C. support
D. problems
2. The opposing force between the molecular particles inside a star is called
A. general relativity
B. the exclusion principle
C. infinite density
D. a singularity
3. The word “offset” could best be replaced by
A. carry
B. arrange
C. overflow
D. counteract
4. It can be concluded from paragraph 3 that light
A. destroys a black hole
B. can barely reveal a black hole
C. does not exist near a black hole
D. originates in spacetime
5. Which of the following is NOT mentioned as the possible fate of an astronaut who falls into a black hole?
A. Experience of amusement
B. Death by gamma rays
C. Knowledge of the universe
D. Destruction by gravity
6. It can be inferred from the passage that black holes are
A. soon to be located and studied
B. a scientific impossibility
C. the key to the entire future of the universe
D. a source of inspiration and entertainment
