What is a black hole and how is it created?
In space there are stars with far greater mass than the sun. When a star’s mass exceeds the total of 20 sun masses approximately, and reaches the stage of “hyper giant” (in which the star emits a huge amount of energy, expands and becomes alarming in size), a violent supernova explosion occurs, leading into the creation of a black hole.
The black holes are objects whose density theoretically tends to infinity. The reason why black holes are not immediately visible is that the gravitational field near them is so strong that even the light cannot escape.
There are black holes that sit "still" and others that rotate, spending electricity. Below I refer mainly to the second kind.
Can we travel through a black hole? This could likely occur under certain conditions.
The first and most important factor is the existence of an exit or else it is likely to be trapped forever in an absolute void of space. The equations of relativity have a particularly interesting property: they are symmetrical. This means that if we get a valid solution of the equation and imagine that time goes backwards then we will get another valid solution of the equation. With the application of this to the solution describing the black holes, we end up with an object known as a "white hole". Essentially, the white hole does exactly the opposite of the black hole. Instead of absorbing objects, it expels them. But this is only one theory which has not yet been proven in the universe. Scientists argue that the creation of a white hole is as difficult as the destruction of a black hole. If we consider a rotating black hole, we would find out that there is the possibility its field to be joined with another field (probably a white hole’s). The combination of a black with a white hole is called a wormhole and it seems likely that an object will be able to pass inside it. The white hole may be located in another dimension even back to the past.
Moreover, let’s assume that we have discovered a wormhole. Unfortunately for us, it will not be easy to be transported to another dimension as desired. This is due to the fact that our entry will cause such a disturbance in the wormhole’s field leading to its dissolution. Even if the field remains stable, during our exit from the white hole we would get burned by the high Gamma and X rays prevailing.
Maybe in a few years and with the right equipment we can take a trip through time. But imagine what consequences this would have for all of us ... What would happen if we met in ourselves in the past and kill him/her? Then will we continue to live? Will anyone really believe that we come from the future? Could we ever return and if we did what would we find? All these certainly seem unrealistic now, but maybe in the future we would dare a trip back to the golden age...
All this may seem easy but we should not forget that time is relative. Everyone understands the concept of "time" in a different way. The measurement of time is not an easy task. Ancient Greeks used two words to describe time: the word "kairos" that symbolized eternity and the word "chronos", describing the cosmic time. Time is like a circle. It has no beginning and no end. It is something that the human mind cannot conceive. Could it be then that we are constantly living, traveling through time?