Black holes are imaginary and theoretical

Stephen HawkingThese are his main theories

Thinking, combining, drawing conclusions: the British astrophysicist had been for many years Stephen Hawking, who died on Wednesday at the age of 76, trapped in his body due to a serious illness (amyotrophic lateral sclerosis) and had to rely on outside help. "What else could he do with his mind, to conquer his own matter?" Says the German science journalist and astrophysicist Harald Lesch, which brings a short video obituary (see below) on the deceased, to the point. Hawking wasn't doing experiments, he was thinking. As a cosmologist, he dealt with the whole thing - and elicited more than one secret from it.

Stephen Hawking was a cosmologist. He dealt with the whole thing.

Harald Lesch

>>> To the big bang

The general theory of relativity of Albert Einstein states that the origin of the universe lies in the Big Bang. After that, this has expanded further and further up to the present point in time. And it continues to expand. Measurements have meanwhile also confirmed that the universe was formed 13.8 billion years ago. Hawking and other researchers have shown that the origin of the universe cannot be explained within the framework of the theory of relativity. In doing so, it reaches its limits. Hawking assumed that there was some kind of precursor universe even before the universe, which eventually collapsed.

Together with Roger Penrose Hawking created a mathematical justification for the fact that the universe was created with a big bang as early as the 1960s. He found out that the singularity, i.e. states in which the observed spacetime (including their metrics) can no longer be defined in a single point or a more complex manifold, are mathematically the same in black holes and in the Big Bang.

>>> To black holes

The theory of relativity also shows that massive giant stars, when their fuel supply is exhausted, explode and then glow. One then speaks of a so-called supernova. The core of the star collapses and collapses. A so-called black hole is created. Hawking and his colleagues have shown that these black holes only have a maximum of three properties, namely mass, angular momentum and electrical charge. In the 1970s, Hawking developed the theory that black holes can not only swallow matter, but also disappear by emitting radiation (Hawking radiation) and slowly evaporating it. This finding was revolutionary for astrophysics. The calculation of Hawking radiation was only possible with the help of quantum mechanics (that is the theory of the smallest particles). Black holes, on the other hand, were explained using the theory of relativity. The great goal of physicists is to bring these two, namely quantum physics and general relativity, together into a so-called "world formula".

>>> What happens to the information?

In the 2000s, Hawking finally revised his theory that objects swallowed by a black hole disappear or enter another universe. Quantum physics is based on the assumption that information is preserved. However, when black holes evaporate, as in Hawking's theory, information is apparently also destroyed. So Hawking developed the theory that objects that are "swallowed up" by a black hole do not simply disappear, but are "spat out" in a different form. This theory is still very controversial.

>>> Introduction of an imaginary time

According to the general theory of relativity, as already mentioned, the universe began in the Big Bang. As for the singularity, this theory failed. That is why Hawking introduced what is known as "imaginary time". This is a mathematical quantity made up of imaginary numbers that makes the difference between space and time disappear. In this imaginary time there is no difference between forward and backward. It has neither a beginning nor an end. With imaginary time, Hawking was able to place the beginning of time on the North Pole. Otherwise this point on the globe is like any other point on it. The laws of nature also apply there. Just as the earth as a sphere has no beginning and no end and thus also no edge, the universe is also closed, Hawking further assumed. Hawking believed that this no-fringe condition was key to the answer to the question of why mankind existed.

Harald Lesch's personal obituary:

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