Astronomers often operate in the position of a theorist or observer. Theorists invent models of reality, which are then verified by observers – they create a description, usually in the language of mathematics, and predict the behavior of a particular object or phenomenon. Models are not reality, but they are an attempt to better or worse describe them. Models that reproduce observed reality exceptionally well, as well as make predictions consistent with other observations, are sometimes elevated to the level of laws of physics, but they are also not a fact, but a description of it. Scientific findings, as opposed to unverifiable and by definition indisputable “unearthed facts”, are subject to modification and improvements. I stress openness to verification and the need for improvement as the essence of science, because these features are sometimes interpreted as unfavorable, when the exact opposite is true.
Humanity has practiced astronomy “forever” and it was initially associated with attempts to understand reality based on religion. Therefore, the first astronomers were more or less priests. Evidence of their activity is, for example, a piece carved from mammoth bone with the constellation Orion marked over 30,000 years ago. Years and similar ancient drawings on a cave wall in Lascaux, France depict the Pleiades, the Summer Triangle, and the Crown of the North.
The ability to predict the future, that is, the movement of the stars, is a mystical skill, but also a practical one. For this reason, buildings such as Stonehenge were built to perform astronomical, religious and social functions at the same time. The practical reason was the desire for an almanac, that is, to mark and predict the passage of time based on archival observations of the sun, moon, and stars, which was important to agricultural societies as crops depended on farming at the right time of the year. The periodicity of astronomical phenomena was accurately described by the Sumerians in Mesopotamia, using the sexagesimal system in calculations – which is why a full angle has 360 degrees, and a minute (arc and time) has 60 seconds. But even in our cultural circle, the calendar still matters: Easter falls on the first Sunday after the first full moon in spring, and spring begins when the day begins to be as long as the night, which corresponds to the well-defined position of the sun against the background of the stars. The mysterious job is to discover new phenomena in the sky. In religious interpretation, a new object, such as a comet, may be a sign comprehensible only to the chosen people; Not a random English word catastrophemeaning catastrophe, is a combination of the Greek words δυσ: bad, me ἀστήρ: a star.
Stonehenge (public domain)
Stonehenge in 3D (public domain)
When creating a calendar, it is helpful to know the positions of the sun, moon, and planets in relation to other stars. The ancient Greeks made great advances in astronomy, dealing with it directly as a branch of mathematics, developing geometric models of what can be seen “by eye”, that is, explaining the movement of the sky around the earth. Aristarchus of Samos was the first to propose a heliocentric arrangement of the planets, and Eratosthenes accurately estimated the radius of the Earth using almost nothing but reasoning, without leaving his library in Alexandria.
Eratosthenes – ancient Greek mathematician, astronomer, philosopher, geographer and poet. He determined the circumference of the Earth and estimated the distance from the Sun and Moon to the Earth. (public domain)
Better and better observations, although still done directly by eye, forced corrections of models, i.e. changing concentric domains into more complex combinations, taking into account eccentric circles, deferrals, staples and, as we say today, optimization of computational resources . The Antikythera mechanism, which dates back to the second century BC, resembles a complex clock and is considered the first astronomical computer.
Antikythera Mechanism – Reconstruction. (public domain)
Antikythera Mechanism – Reconstruction (Public Domain)
When we think of the history of astronomy, we tend to focus on the ancient Greeks and Romans, but similar advances were made, often independently, by astronomers from China, South America, India, Arabia, and Persia.. In particular, thanks to the meticulousness of translators from the Middle East, some Greek works have survived until the Middle Ages. It is no coincidence that most of the stars bear Arabic names, because by the 10th century AD, the Arabs had created a network of excellent observatories, innovative measuring devices (astrolabes) and catalogs of star positions, which were used, among others, by Nicolaus Copernicus. If the Greek contribution to the development of astronomy was geometry, then the Arabs developed algebra, which is a very powerful tool for solving equations with unknowns. At the end of the Middle Ages (15th century), the need for changes in thinking, due to – let’s be honest – lack of success in modeling planetary motion, was unbearable.
Copernicus, the direct cause of the revolution, the author of the book “De Revolutionibus orbium coelestium” used in his heliocentric model of the solar system (commissioned by the Vatican, by the way, to improve calendar calculations), the knowledge accumulated by many of their predecessors. Use Greek accounts and ideas (including Aristarchus of Samos) and archival star catalogs created by Arab scholars. His original model was much less accurate than today’s highly accurate geocentric models, and was initially not controversial at all. The interpretation of the results caused a scandal: the universe turned out to be much larger than previously thought, and the hypothesis that any star could be a sun similar to ours, which in turn is completely uncharacteristic, hit the groundwork for “revealing” facts.
Accounts of Aristarchus of Samos (Public Domain)
Until the beginning of the seventeenth century, astronomical knowledge was gained with the naked eye: the positions of objects in the sky were measured, Using a sophisticated protractor, like the one in Jean Matejko’s famous Copernicus painting. The situation changed after the construction of a telescope in Holland, an instrument consisting of lenses that has been known since ancient times. Galileo, using a telescope about the size of a tube of a roll of paper towels, saw for example craters. These include the cratered surface of the Moon, the phases of Venus, the movement of Jupiter’s moons, single stars in the Milky Way, or spots on the Sun. The extraterrestrial world turns out to be changeable and imperfect, in clear contradiction to the Aristotelian doctrine of the perfect harmony of heaven. It was the shock from which modern science arose (“ours” also participated in it; Jan Hewelius of Gdańsk – a true Renaissance man, a successful businessman and at the same time a scientist – made accurate maps of the moon in the first half of the 17th century).
The end of the seventeenth century marks an almost mystical triumph of “the inexplicable potency of mathematics in the natural sciences,” to use the title of an essay by the great twentieth-century physicist Eugen Wegener. At that time, the calculus of Isaac Newton and Wilhelm Leibniz was created (part of mathematical analysis), which turned out to be an excellent tool for creating celestial mechanics. Acting as an accurate clock, the planets move around the Sun in ellipses, limited by the force of gravity, proportional – as we remember from school – to the product of masses, and inversely proportional to the square of the distance. The mathematical description worked so well that deviations from predictions and more careful observations made it possible to discover hitherto unknown planets: Uranus (William Herschel, 1781) and Neptune (Johann Gottfried Galle, 1842). The bulky telescopes of the 17th century were replaced by easier-to-build telescopes with mirrors instead of lenses. Thanks to them, they reached farther and farther into space, discovering less bright and more subtle effects, such as changes in the brightness of stars or the fact that many of them are in binary systems.
Eugene Weiner – American physicist and mathematician of Hungarian origin, Nobel Prize laureate in Physics. (public domain)
was the next step The invention of photography in the mid-nineteenth century (John Draper, 1840). From this moment, the archiving of observations, even for decades, and the possibility of documenting phenomena begins. They also learned to use the phenomenon of dividing light by a prism into individual colors, although Newton had already studied this phenomenon hundreds of years earlier. The study of the light spectrum, that is, the spectrum, showed the first researchers (Joseph von Fraunhofer) the wonderful richness that is contained in the indistinct beam of light. Contains detailed information about the substance that was emitted! It turns out that stars are composed of chemical elements, just like those on Earth, as well as those on Earth. Once again, the heavens became more Earth-like, and the prism became an instrument similar to Galileo’s telescope.
It seems unlikely Until the beginning of the 20th century, astronomers were unaware of the existence of other galaxies, let alone the size of the universe. It is not known why the stars shine so brightly, and the sky is known only in a narrow band of visible light. However, this was the calm before the storm, for at the same time the last great revolution was taking place, connecting as closely as possible the largest (the universe) with the smallest (elementary particles). as a result of Physicists and astronomers – astrophysicists – now have a theory of the smallest (indivisible!) Components of matter, that is, quantum, and a better theory of gravity: the theory of relativity, in which the aforementioned Newtonian gravitational force does not exist (!) and space changes and ripples, which affects at the pace of time.
In about 50 years since the beginning of the 20th century, astronomy has completed a set of practical and magical skills for seeing the sky in waves of “invisible” light, of the longer radio wave range (first observations in the 30s), through infrared (beginning of the century), ultraviolet (40s), to the shortest and most active – Roentgen and gamma rays (First notes in the 60s). It became possible to detect previously unexpected elementary particles associated with previously unknown fundamental interactions (neutrinos) and electrically charged cosmic particles that constantly bombard our planet, as well as to detect vibrations of space-time itself, that is, gravitational waves. The scope of our interest in occult phenomena has grown increasingly so that the imaginations of theorists are now fueled by increasingly complex and computationally expensive computer simulations and models of reality “dreamed up” by increasingly intelligent AIs. We are entering interesting times.
Michael Pager He is an astronomer who, instead of looking through a telescope, listens for earthquakes in space-time caused by distant cosmic cataclysms. For what purpose? Using miles of triangles filled with fantastic emptiness, he explores the world of exotic elementary particles, peers inside neutron stars (the densest objects in the universe), and searches for evidence that Einstein was wrong–all with the help of properly trained AI.
