There are many mysteries that are yet to be truly understood in the unknown universe. A popular phenomenon called black holes are subject to many fiction based mediums where the physics portrayed are yet to be proven. One of the most popular theories that have been portrayed in fiction would be the “wormhole” theory. This theory proposes that black holes are worm holes that serve as a way of rapid transportation across space and time3. Although this theory can be incorporated into movies and books to create thought provoking and interesting plots, science has proven that this theory is very unlikely. Unfortunately, if one was to desire to test the wormhole theory first hand, they would have to travel very far because the closest black hole is 1,600 light years away from earth4. Aside from black holes being a popular subject for fictional theories, science has strong evidence that proves what a black hole is, what it can or cannot do, and the process that would occur if one was to decide to enter it.
The term black hole was created quite recently in 1969 by an American scientist named John Wheeler. John Wheeler coined the term for his illustration based on an idea that was founded at least 200 years ago. During this time there were two theories about light that were established. The first theory is that light is a wave, and the second theory is that light is made out of particles. Since light is made up of particles, it can be reasonably assumed that these particles could be affected by gravity3. In the past, people thought that light particles traveled at an infinite speed. However, that has since been disproven and it is known that light travels at a finite speed which means that gravity has an impact on light5. With these theories, a man named John Michell wrote a paper in 1783 in the Philosophical Transactions of the Royal Society of London about the possibilities of stars having a gravitational field that was so strong that light could not escape. Since no light was able to escape, these stars appeared to be black voids in space hence the name “Black” hole3.
Black holes are the last evolutionary stage of stars that have the size of at least 10 to 15 times of our sun. These stars are known as giant stars, and during the last stages of their lives they collapse into themselves and cause an explosion called a supernova. The supernova causes most of the star to break apart and travel outwards into space2. The star is than left with a cold remnant where the fusion of colliding hydrogen atoms to form helium and heat to create light no longer exists. Since there is no longer any nuclear fusion that can create constant outward pressure in the star, the force of gravity alone causes the star to collapse into something infinitely dense. All matter that fall into a black hole must past the point of no return which is also called the event horizon2. The event horizon would also be what scientists are observing when analyzing a black hole. Since black holes possess a strong force of gravity, neighboring starlight and gases entering the event horizon can be seen by scientists. If in the case where stars are orbiting a particular spot in space, it is often predicted that these stars are orbiting around a black hole. A black hole that has a particularly strong force of gravity can pull the outer gases of certain stars and form something called an accretion disk1. The gas from the accretion disk spirals towards the centre of the black hole and heats with increasingly high temperatures. The heat from the gas produces x-rays which emit at all directions when in the black hole. NASA is able to use telescopes to view these x-rays and learn more about the properties of black holes. During the entrance of the event horizon it is impossible to leave a black hole’s grasp because according to the theory of relativity, nothing can travel faster than the speed of light and it takes something that is faster than the speed of light to escape3.
Black holes can attract unlimited amounts of matter which simply makes the phenomena denser as time goes on. Although there is a lot of matter that fall into black holes, the size of black holes are relatively small in size. For example, a black hole that has the same amount of mass as our sun could have a radius of only 3 kilometres. A black hole that has a million-solar-mass (three million times the mass of our sun) would only have a radius of about three million kilometres2. In fact, NASA has discovered a massive black hole named Sagittarius A at the center of our very own Milky Way6. Since black holes are continuously collecting numerous amounts of matter, black holes may have the mass of around 10 to a 100 billion stars3!
Although stars, gases, comets, and asteroids have been seen as subjects to black hole oblivion, people often wonder what it would feel like when entering a black hole. Once someone enters a black hole past the event horizon, they have passed the point of no return. A human being will simply die before even reaching the black hole and this is how it happens8. The force of gravity around ones feet is much stronger than the force of gravity being imposed on one’s head. The same principle applies to somebody here on earth. The closer you are to earth, the stronger the force of gravity that is applied. Since the earth however, is so massive in size, there is not much of a difference being applied to your feet compared to your head7. In the case of black holes, they are so small in size that the difference between the force of gravity acting on your feet and head is massive. Assuming that you are entering into a black hole feet first, the immense force of gravity acting on your feet could be tens of thousands of times larger than the force acting on your feet. This process called “spaghettification”(a term coined by a British astrophysicist named Sir Martin Rees) where the force of gravity exceeds the molecular force that binds human flesh. As a result, your body will split into two, and both two pieces of your body will repeat the same process and split again7. This process is repeated until your body turns into a stream of atoms towards the dark abyss. However this experience may not seem all that bad in the grand scheme of things8. Spaghettification will provide the opportunity to experience the effects of the curve of space and time which was predicted by the General Theory of Relativity by Einstein. From an observer it would seem to look like you would be slowing down as you approach the black hole until it seems as you have frozen, turned red, and disappeared. The person who is approaching the black hole assuming that their body is still intact to see things, will observe everything that has fallen into the black hole in the past, and everything that will fall into the black hole in the future7.)
In essence, scientists have come very far in understanding what black holes are. However, there is an enigma surrounding what lies within the very center of every black hole9. The center of a black hole is called a singularity which has infinite density. The mystery in this case, is the according to the theory of general relativity, a place of infinite density is a place where time and space ceases to exist9. Nonetheless, science has come so far to understanding this fascinating phenomena. In due time, there is no doubt that the enigma that is a the singularity will be understood to discover not only new properties of black holes, but answers to many other mysteries within the unknown universe.
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