What is a black hole? Pretty much any hole with the absence of light is a black hole. In this case, however, I’m talking about the ones in space. Black holes were a theoretical concept for a long time. Karl Schwarzschild developed the modern idea of the black hole from Einstein’s Theory of General Relativity. Through the theory of relativity, Schwarzschild calculated if matter was compressed to a single point, known as a singularity, this matter would be condensed to a point from which nothing could escape, not even light. Hence, the black hole.
Black holes are formed as a result of varying astronomical conditions. Depending on the conditions, the results may vary. At present, there are four types of black holes. The first is a primordial black hole. These black holes are believed to have formed soon after the Big Bang took place. They are purely theoretical and have a mass less than the earth.
The second is a stellar mass black hole. These black holes have a solar mass of 4-15 times our own sun and develop about as the result of the star going supernova when it dies. It is worth mentioning that one solar mass is the equivalent of the mass of our sun. The mass of our sun is 333,000 times the mass of the Earth.
The third type of black hole is an intermediate black hole. They have a mass several thousand times greater than our sun. It is not known how they are formed but there are three theories. The first is when two stellar mass black holes merge together through gravitational pull. The second theory is two massive stars crash together and form the black hole at that particular point of contact. The third theory is they are primordial black holes.
The fourth type is a supermassive black hole. These are the biggest of all with a mass between 10 to the 6th or 9th power. This type is located at the center of most large galaxies. The formation of the supermassive black hole still lies in the realm of theoretical.
Considering the fact that black holes are black and space seems to be black, how can scientists ever hope to find one? One way is to locate the Event Horizon of the black hole. The Event Horizon can be roughly summed up as the point of no return. It is a location surrounding the black hole when once crossed, exit is not an option anymore. It is the location around the black hole that light bends as it approaches, for if crossed not even light can escape.
It is like the edge of a cliff. A person can stand balanced on the edge of that cliff. However, a slight shift in weight towards the drop and the person is falling over. One can also think of it as a non-spinning whirlpool and a boat. Provided the boat stays far enough away from the watery drop, it has the power to navigate through the pull towards the center. If the boat gets too close the center then it will be pulled into a watery drop, unable to power its way out.
Finally, imagine space as a rubber mattress. In the middle of the mattress, I place a 10-kilo metal ball. This metal ball will cause a depression in the mattress. Outside the metal ball, the mattress will start to curve downward in a funnel-like manner. Let’s say I also have a glass marble. I place this glass marble on the rubber mattress. Depending on the distance from the 10-kilo metal ball in the center of the mattress, the glass marble does not move toward the center of the mattress. However, if the marble gets too close to the metal ball, it will roll into the cone in the center.
My reporting on black holes may seem a little out-of-the-blue but it is not. This next video shows proof of the existence of black holes. This footage was taken from the Event Horizon Telescope and just released. With my previous discussion of the Event Horizon, it is obvious why the telescope is so aptly named.