Black Holes Essay

Black Holes

Black holes are points in space where there are extreme gravitational pulls that prevent anything, including light, from escaping. The reason for such a strong gravitational pull is due to vast amounts of matter being contained in a small amount of space. Stellar black holes form from stars with a mass greater than 20 solar masses and can be a result of gravitational collapse. Gravitational collapse is a result of the star’s internal pressure not being able to resist the stars own gravity. When the star is exhausted of its nuclear fuel such that it cannot maintain a high enough temperature it will begin to collapse under its own weight (Seidel 2011). As the star collapses it causes a supernova which blasts the outer layers of the star into space while the core completely collapses under its own weight. If the remnant core left behind exceeds 3 solar masses there are no known forces that can prevent the core from completely collapsing into a black hole (p. 568 Bennett et al. 2013)

Since black holes do not emit light and completely absorb light near them it would seem as if they would be impossible to detect. While black holes do not emit light, the effects of black holes are detectable. Due to a black hole’s strong gravitational pull any matter being pulled into the black hole accelerates and heats up. This causes the atoms to be ionised and when they reach high enough temperatures they start emitting x-rays which can be detected and observed from Earth (Netting 2014). Studying x-ray binaries are an excellent way to detect stellar black holes as binary systems provide sufficient matter to supply the black hole’s x-ray emissions. Cygnus X-1 is an example of a black hole detected through the observation of a binary x-ray ...

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...leted of its nuclear fuel and lost its outer layers. When a small to medium (less than 10 solar masses) main-sequence star begins to run out of fuel in its core, the core will begin to collapse where hydrogen on the edges of the collapsed core can be compressed and heated (Chandra 2012). The nuclear fusion of this new hydrogen will create a new gush of power that will make the outer layers of the star to expand out; this is known as the red giant phase. In the red giant phase over millions of years, all of the stars energy supplies are used up leaving behind a hot core that is still surrounded by the expanded outer layers. The outer layers are eventually expelled by stellar winds which end up creating a planetary nebula and the hot core left behind forms a white dwarf star where the pull of gravity is supported by degeneracy pressure (p. 538 Bennett en al. 2013).