250 thousand years ago, in a night of intensely starry pitch, a first Homo sapiens he gazed at the vault of heaven, as he had done since he had known himself. Star gazing heightened his primal awareness and refracted his dreams.
That night, the continued awareness of the regularity of the movement of the stars, the result of years of repeated observations, illuminated his imagery thinking: still speechless, he was aware that he was the center of everything he knew. In other words, in addition to living in the Garden of Eden, he glimpsed the certainty that he was the center of the Universe, we would say today.
This anthropocentric certainty of human centrality in the Universe, the result of our cosmic myopia, lasted for hundreds of thousands of years and built cosmogonies, myths and religions, fortified by different human civilizations.
Although the Greek Aristarchus of Samos (310-230 BC) suggested, as far as is known, that the Earth should revolve around the Sun, the Earth's centrality continued unabated until the XNUMXth century of our era.
It was Nicolaus Copernicus, based on thousands of astronomical observations with the naked eye, who proposed the then heretical Heliocentric Theory: the Sun was the center of the Universe and all the planets then known orbited around it. In other words: the Sun was the center of the Solar System.
It was with Galileo Galilei (1564-1642) – with his new and methodical instrumental and scientific skill in observing the sky with the brand new telescope, that he himself improved it, adapting it with what the technique of the time allowed for the best astronomical observation – that the human brain concludes, in the face of experimental evidence observable by anyone, that Copernicus' hypothesis was right, that the Sun had to be the center of the observable "machine of the world." The four moons of Jupiter and the phases of the planet Venus, which Galileo observes in 1610, supported it.
We owe to French astronomer Charles Messier (1730 – 1817) the intensive mapping of celestial bodies only visible through the telescope, which gave rise to what was designated, in his honor, by Messier's catalog of “objects” of the deep sky.
But despite having recorded nebulae, star clusters and what we now know to be galaxies in their catalogue, Messier and his contemporaries continued to regard the Sun as the center of the human Universe.
This solar centrality begins to be eroded with the explored glow of the Milky Way. But it should be noted that, until the beginning of the XNUMXth century, the Milky Way was the only galaxy understood as such. It was taken for granted that everything that could be observed, with the best telescopes of the time, would fit inside the Milky Way. From other points of view, nothing was thought to be seen beyond the Milky Way, which is to say that the Universe was limited to our galaxy.
It was Edwin Hubble (1889-1953) who discovered, in 1923, using the Hooker telescope at the Mount Wilson Observatory, in the United States of America, that what was then thought to be an interim nebula in the Milky Way was, in fact, of a “new” galaxy, Andromeda, located far beyond the limits of our galaxy.
He also discovered that this and other galaxies soon after identified moved away from each other at speeds proportional to the distances that separated them. The “new” and stunning Universe was expanding.
The Milky Way was one of many, many other galaxies and was by no means the center of the Universe! the mind of Homo sapiens it expanded with cosmic wonder.
And, in the 90's of the XNUMXth century, with the fantastic technical development in the sensitivity of the most modern telescopes, it was possible to detect “very small” oscillations in the position of the stars and periodic variations in their brightness: the existence of extrasolar planets, or exoplanets, new worlds orbiting the celestial stars.
Since then, more than 30 exoplanets have been detected and it is estimated that between 50 to XNUMX percent of visible stars are orbited by planets.
One telescope in particular, NASA's Kepler Space Telescope, contributes to the discovery of most of these exoplanets, in particular of several rocky planets with dimensions similar to Earth and at distances from their stars that could allow the existence of liquid water : orbit what is called, with much hope, the "living zone"!
The Kepler space telescope, which began exploring starlight in 2009, ended its functionality this week as its fuel ran out.
But NASA said there is still much more to discover with the as-yet-unstudied data than Kepler. captured and sent to Earth. There are still many worlds to unravel in this amazing Universe…
Author Antonio Piedade
© 2018 – Science in the Regional Press / Ciência Viva
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