Why are the nights dark if there are countless stars? Perhaps, at some point in your life you have questioned that fact. In the same way, in 1823, a retired ophthalmologist, devoted to astronomy, was invited. Heinrich Olbers, asked the same question from the second floor of his house, turned into an amateur laboratory. However, he was not the first person to do so.
At the beginning of the 17th century, the astronomer Johannes Kepler Astronomer a century later used the same question to prove that the universe was infinite Edmund Halley He put it as a “temporary fix,” assuming that the sky would not shine evenly at night because the stars were not evenly distributed.
Olbers' Paradox
However, the obscurity of that answer was not enough to calm the desire for knowledge, and in the first third of the 19th century, Heinrich Olbers put confusion back on the table. According to him, if the universe is infinite and has no beginning and no end, then there must be one Countless stars Incandescent lights are evenly distributed.
Following this reasoning, and using expressions relating the intensity and luminosity of light, he said that every point in the sky must be as bright as the surface of a star. That is, every line of sight that leaves Earth must meet a star on its path. Now, his predictions were endless with what his eyes saw: the sky contained Black areas Without any shine.
Confused by the result, Olbers proposed a solution to explain what was happening. So he felt he had to do it for the sole reason that the sky was dark There is something Blocks light from stars in space. Although this theory seems crazy today, in the hundred years that followed the paradox, no one disputed Olbers' statement. However, after some time, various solutions began to be presented that finally put the problem to rest without any apparent explanation.reasonable”.
Theory of Relativity
One of them is the general theory of relativity, which contains two key points that resolve this paradox in a scientific way. First, if we assume that the universe There was a beginning, the Big Bang, and then only the light of a limited number of stars reaches us. So, the paradox seems straightforwardly resolved: light has a finite speed, and since the universe is 13.8 billion years old, we are the only ones who perceive it. Stars are located less than that distanceThat means a limited area.
Redshift: A Powerful Tool for Understanding the Big Bang Theory
On the other hand, the universe is expanding and if the stars are moving away from us, their light is movingmoving towards red. This effect precisely causes a decrease in the light's intensity, which means that its light does not reach us completely, and we cannot reach the infinity of stars that Olbers had hoped for.
Mandelbrot solution
For his part, the astronomer Benoît Mandelbrot proposed a very different way to solve the problem, completely ignoring the theory of relativity. Thus, this scientist proved that luminosity can be finite and black areas can exist in the night sky as long as the dispersion of galaxies is considered. fractional systemThat is, the way galaxies appear repeats itself according to the same pattern over and over again at different scales.
With this hypothesis, the set of all galaxies formed together is, therefore, Fractal, isotropic and homogeneous in all directions of space. This is a hypothesis that has been considered the basis for many subsequent studies of the structure of galaxies, yielding results that are consistent with most experimental observations and empirical data.
