Black Holes

Black Holes

Our galaxy, as we know it, is a vast and complex dimension of our solar system. It has been a mystery to many scientists for generations. It's the question that drives us to discover- What truly is out there? This may be why it interests us to learn about all that we cannot see. Humans have known the existence of stars since they have had eyes, and see them as white glowing specks in the sky, but there is so much more out there. The real mystery lies beyond the white glowing specks we see, but in the things we cannot see in the night sky such as black holes.

Before one can learn about black holes, one must know about the white glowing specks in the sky - stars. One might wonder what a star has to do with a black hole, but without the presence of a star, a black hole could not be formed. The development of a star is because of a hydrogen atom. Stars form from the condensation of clouds of gas that contain hydrogen. (Bunn) The atoms of the cloud are then pulled together by gravity. The energy produced from this cloud is so great that when it first collides, a nuclear reaction occurs. The gases within the star start to burn continuously. The hydrogen gas is usually the first type of gas consumed in a star and then other gas elements such as carbon, oxygen, and helium are consumed. This chain reaction of explosions fuels the star for millions or billions of years depending on the amount of gases there are.

Stars are born and reborn from an explosion of a previous star. Particles and helium are brought together the same way the last star was born. Throughout the life of a star, it manages to avoid collapsing. The gravitational pull from the core of the star has to equal the gravitational pull of the gasses, which form a type of orbit. When this equality is broken, the star can go into several different stages. Some stars that are at least thirty times larger than our sun can form black holes and other kinds of stars.

Stars explode at the end of their lifetime, sometimes when they explode the stars leave a remnant of gasses and dust behind. What the gasses come together to form depend on the size of the remnant. If the remnant is less than 1.4 solar masses it will become a white dwarf, a hot dead star that is not bright enough to shine. If the remnant is roughly 1.4 solar masses, it will collapse. (Cowen 57) "The protons and electrons will be squashed together, and their elementary particles will recombine to form neutrons." The results from this reaction are called a neutron star. The neutrons in the neutron star are very close together, so close that the pressure prevents the neutron star to collapse onto itself. The closeness of the neutrons in this star makes it very dense. (Lutgens and Tarbuck 428) If the remnant of this giant exploding star is larger than three solar masses or ten times our sun, it becomes a black hole. A black hole is one of the last options that a star may take. (White)

In the 18th century scientists started to research the after effects of a large star such as a supernova exploding. This phenomenon made them question what would happen of the gas and dust left behind after such a big star died. The idea of mass concentration so dense that even light would be trapped goes all the way back to Laplace in the 18th century. The first scientists to really take an in depth look at black holes and the collapsing of stars was Professor Robert Oppenheimer and his student, Hartland Snyder, in the early nineteen hundreds. They came up with the basics of a black hole from Einstein's theory of relativity that if the speed of light was the most speed over any massive object then nothing could escape a black hole once in its grasp. These researchers showed that when a sufficiently massive star runs out of fuel, it is unable to support itself against its own gravitational pull, and it should collapse into a black hole. In general theory of relativity, gravity is a manifest of the curvature of the space-time. (Cowen 56)

"Einstein's general theory of relativity showed that light, though it does not react to gravity in the same way as ordinary matter, is nevertheless affected by strong gravitational fields. In fact, light itself cannot escape from inside this region." (Bunn)

Massive objects distort space and time, so that the usual rules of geometry don't apply anymore. Near a black hole, this distortion space is extremely severe and causes black holes to have some very strange properties.

A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. (Bunn) After a black hole is created, the gravitational force continues to pull in space debris and other types of dust to help add to the mass of the core, making the hole stronger and more powerful. Most black holes are spinning; the spinning of the black hole allows more debris to become a part of its ring which is called the event horizon. (Bunn) The debris spins within the ring until it becomes a part of the center of the black hole adding to the mass of the core, making the hole stronger and more powerful. The event horizon is also known as the boundary.

The event horizon is the point where the black hole's gravitational pull begins. Once you cross the event horizon, there is no turning back. The only way that something can escape a black hole's event horizon once it has entered, is by exceeding the escape velocity. However this would be highly unlikely, because the escape velocity means moving faster than the speed of light! Since moving faster than the speed of light is impossible, so is escaping a black hole's gravitational pull. In order for the black hole to swallow something up, that thing will have to pass the event