In search of a peace system
The starry sky at all times occupied the imagination of people. Why do stars light up? How many of them shine in the night? Are they far from us? Does the stellar universe have boundaries? Since ancient times, man thought about these and many other questions, sought to understand and comprehend the structure of that big world in which we live.
The earliest representations of people about him are preserved in fairy tales and legends. Centuries and millennia passed before the science of the Universe arose and received a deep substantiation and development, which revealed to us a wonderful prostate, an amazing order of the universe. Not without reason in ancient Greece it was called Cosmos and this word originally meant “order” and “beauty.”
World systems are ideas about the location in space and the motion of the Earth, the Sun, the Moon, planets, stars and other celestial bodies.
2. A picture of the world.
In the ancient Indian book called Rig Veda, which means the Book of Anthems, one can find a description – one of the very first in the history of mankind – of the entire Universe as a whole. According to the Rig Veda, it is not too complicated. It contains, first of all, the Earth. It appears to be an unlimited flat surface – “vast space”. This surface is covered from above by the sky. And the sky is a blue, star-lit “vault”. Between heaven and earth is the “luminous air.”
It was very far from science. But something else is important here. Remarkable and grandiose is the daring goal itself – to grasp with thought the entire Universe. From this comes the assurance that the human mind is able to comprehend, understand, unravel its structure, and create in its imagination a complete picture of the world.
3. The movement of the planets.
Watching the annual movement of the Sun among the stars, ancient people learned to determine in advance the onset of a particular time of the year. They divided the sky along the ecliptic into 12 constellations, in each of which the Sun is located for about a month. As already noted, these constellations were called zodiacal. All of them except one bear the names of animals.
Ancient people associated their agricultural work with the pre-dawn sunrise of one or another constellation, and this is reflected in the names of the constellations themselves. So, the appearance of the constellation Aquarius in the sky indicated the expected flood, the appearance of Pisces – the upcoming fish course for throwing caviar. With the morning appearance of the Virgo constellation, bread harvesting began, which was carried out mainly by women. A month later, the neighboring constellation Libra appeared in the sky, at which time the weighing and counting of the crop was taking place.
Even 2000 years BC. e. Ancient observers noticed among the zodiac constellations five special stars, which, constantly changing their position in the sky, pass from one zodiac constellation to another. Subsequently, Greek astronomers called these luminaries planets, that is, “wandering.” These are Mercury, Venus, Mars, Jupiter and Saturn, which have preserved the names of the ancient Roman gods in their names to this day. The Moon and the Sun were also ranked among the wandering luminaries.
Probably, many centuries passed before the ancient astronomers managed to establish certain patterns in the motion of the planets and, first of all, to establish time intervals after which the position of the planet in the sky with respect to the Sun is repeated. This period of time was later called the synodic period of the planet’s revolution. After this, the next step could be taken – to build a general model of the world in which a specific place would be assigned for each of the planets and using which it would be possible to predict in advance the position of the planet for several months or years in advance.
By the nature of their movement in the celestial sphere with respect to the Sun, planets (in our understanding) are divided into two groups. Mercury and Venus are called internal or lower, the rest – external or upper.
The angular velocity of the Sun is greater than the speed of direct motion of the upper planet. Therefore, the sun is gradually overtaking the planet. As for the inner planets, at the moment when the direction to the planet and the sun coincides, the planet joins the sun. After the Sun has overtaken the planet, it becomes visible before sunrise, in the second half of the night. The moment when the angle between the direction to the Sun and the direction to the planet is 180 degrees is called the opposition of the planet. At this time, she is in the middle of the arc of her backward movement. Removing the planet from the Sun 90 degrees to the east is called the eastern quadrature, and 90 degrees to the west – the western quadrature. All the planets mentioned here relative to the Sun (from the point of view of the Earth observer) are called configurations.
Excavations of ancient cities and temples of Babylonia revealed tens of thousands of clay tablets with astronomical texts. Their decoding showed that the ancient Babylonian astronomers carefully watched the position of the planets in the sky; they were able to determine their synodic periods of circulation and use this data in their calculations.