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 the sun, the exclusion
principle - the resistence 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 spacetime, a region where gravity is so intense that
nothing, not even light, can scape 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.
(Gallangher, Nancy - Delta's key to the TOEFL test)
Responda o teste:
(UFLA MG)
With what topic is paragraph 2 mainly concerned?
a) The cause of a black hole.
b) The theory of relativity.
c) Rapid gravitational collapse.
d) How to build a model of a black hole.
e) The size of the stars.

Responda obrigatoriamente em PORTUGUÊS:
1- O que o texto diz sobre a localização dos buracos negros e o que isso promoveu para escritores, físicos e astrofísicos?

2- De acordo com o texto, como é formado um buraco negro? Explique.

3- O que aconteceria com um objeto que caísse em buraco negro? Explique com argumentos do texto.