Most commonly known as the point of no return, the event horizon is an astronomical point that has puzzled even Stephen Hawking, famous for his controversial theories towards black holes. It is a sphere-like boundery surrounding the singularity of a black hole (Couper, H., & Henbest, N. 1996). This mysterious outline is made up of millions and millions of photons. In the region where the photons are located, the gravity is too strong to allow them to escape, but not strong enough to pull them into the black hole (Couper, H., & Henbest, N. 1996). The numerous photons remain motionless, unable to direct itself in anyway, marking the boundary known as the event horizon (Couper, H., & Henbest, N. 1996). It is important to remember that the event horizon is the point that if crossed, the speed (escape velocity) needed to escape the black holes gravitational pull exceeds that of the speed of light. Yet, being on the exterior of the event horizon does not mean that there is no gravitational pull on the other side of this invisible wall of photons. Even if you have not passed the event horizon, escape is still possible, yet very unlikely (Couper, H., & Henbest, N. 1996).
The event horizon was, surprisingly, not discovered by Stephen Hawking, but by another man named Karl Schwarzschild (Couper, H., & Henbest, N. 1996). This physicist and astronomer used Albert Einstein’s theory of general relativity to create an equation that proved the existence of a “magic circle” through which nothing could escape. The name: “Magic Circle” was later changed to the present day title, the event horizon (Couper, H., & Henbest, N. 1996).
Stephen Hawking believed that in space, there are many "virtual matter particles" (Ferguson, K. 1991). They are invisible, but prove to exist due to their reactions and effects on objects sorrounding them. Around the region of the event horizon, these particles, travelingu in pairs (positive and negative), were attracted to the mysterious outline. The negative particle would be caught inside the event horizon, and sucked into the black hole. Thus, this originally virtual particle was made into a real particle (Ferguson, K. 1991). We must acknowledge the fact that this process is being repeated constantly and in large numbers all around the black hole. To the observers of black holes, these positive particles are seen as a sort of radiation (Ferguson, K. 1991). Hawking called this the Hawking Radiation. This proves that a black hole can get smaller and eventually evaporate. However, this contradicts with his first theory that states that black holes can never get smaller due to the placement and functions of the photons that make up the event horizon. But to any thinking person, this statement doesn’t make any sense. If nothing can escape the black hole, it is impossible for it to get smaller and disappear. But Hawking came up with another statement that proved this contradiction wrong. According to Ferguson, when the black hole changes the virtual particles into real particle, it loses energy. When the black hole takes this NEGATIVE energy in, it takes the energy OUT of the black hole, therefore making it smaller because when something has less energy, it has less mass (Ferguson, K. 1991). Hence, Albert Einstein’s famous equation: E=mc2
"...the event horizon is the point that if crossed, the speed (escape velocity) needed to escape the black holes gravitational pull exceeds that of the speed of light." 5