Einstein's general relativity is, to this day, the best and most accurate theory of gravity in existence. Its publication in 1915 was a radically different way of understanding the universe. Since then, numerous scientists have set out to study and seek solutions for the equations of German physicist. Each solution describes a specific space-time, and some of them sometimes contain unique, better known as singularities, where space-time "breaks" (curvature becomes infinite). They are places where matter is in such extremely dense conditions that the laws of modern physics are not valid, which makes it necessary a new theory capable of explaining gravity on such a small scale. Physicists and mathematicians continue to try to decipher the nature of these peculiar points of the universe, which is one of the greatest challenges of science.
In the real world, singularities arise in some processes of gravitational collapse, when a massive object (such as a sufficiently large mass star) finishes its fuel and begins to contract due to its own weight, concentrating each more mass in less volume. Einstein's equations predict that if the body has enough mass, the collapse will continue until the star's mass is concentrated at a single point. That point is a singularity,
but where are these points in our universe? In 1969 the British scientist Roger Penrose formulated the so-called weak version of the conjectura of cosmic censorship, which argues that singularities must be isolated from the rest of the universe inside black holes. In this way, regions where equations cease to make sense are hidden from the sight of any observer outside them. This implies that every star that collapses and forms a singularity must end up being a black hole,
Penrose attempted to refute the validity of cosmic censorship by studying the energy and total area of black holes
It was Penrose himself who in 1973 tried to disprove the validity of cosmic censorship by studying the energy and total area of black holes. Specifically, he established a relationship of inequality between these two magnitudes, which is valid as long as cosmic censorship is true. It is a test of fire for cosmic censorship, for the existence of space-times where such a relationship was not fulfilled would be invalidated. So far this has passed important evidence (including that of its own author) and its validity has not been refuted, which has probably made it the greatest challenge that general relativity faces today.
Apart from being an interesting mathematical problem, this conjecture could have important physical consequences in the real universe. The theory of relativity is deterministic, that is, the mathematical model that describes the universe in an "instant of time" gives rise to a single future evolution of it. In other words, the information contained in a "photograph of the universe" would predetermine all events to come,
In a universe where cosmic censorship was violated, there would be so-called "naked" singularities, which would not be inside black holes. From these uncovered singularities could come out of matter and radiation and reach us
In a universe where cosmic censorship was violated, there would be so-called "naked" singularities, which would not be inside black holes. From these uncovered singularities could come out of matter and radiation and reach us. For example, the trajectory of an astral object could be suddenly modified by a gravitational pulse that came out of a bare singularity, removing it from the orbit established by general relativity. Thus, the cause-and-effect relationships of nature could be seriously altered, and relativistic determinism would crumble. The immediate consequences of our actions could be very difficult to foresee, and in that case we would be miated in tremendous uncertainty. To what extent would it make sense to talk about freedom and responsibility in our actions if our lives were subjected to extreme randomness
Although there are mathematical models of the universe where naked singularities arise, it is not known whether in nature the conditions necessary for their formation can take place, and therefore their actual existence in the universe is today a question.
"The most beautiful experience at our fingertips is mystery," said Albert Einstein. If Penrose were right with her conjecture, all the unpredictability generated by the singularities would be enclosed inside the black holes, completely inaccessible, and save the relativistic determinism. In such a case the only way to approach the mysteries of singularities would be the beads and equations with which human beings try to understand the cosmos,