The first thinkers that have thought about the formation of the world were the three wise men from Miles: Thales, Anaximander and Anaxinenes.
All the thinkers have in common that they see a primeval matter or force as prerequisite. This primeval matter arises from nothingness.

Thales of Milet (ca.625 – 546 BC) took water to be the primeval matter of all things. He came to this conclusion because land (the earth) swims on water (the sea).

Anaximones of Milet (about 585 – 528 BC) developed a theory of the infinite being the primeval energy of the world. This energy contains all the contrary elements such as thick/thin, cold/warm, solid/liquid. Anaximander could not explain the primeval substance itself, but was convinced that eternal movement was in it, that would bring forth the elements. From this movements the elements hot and cold form and through their union liquid forms. From the liquid formed the sea in which life developed that moved to the land once it had dried.

Anaximenes of Milet (about 544 – 484 BC) saw in the air the primeval matter of all things. Thinned out the air would become fire, thickened wind, clouds, earth, water and stones. Even the souls of living beings are made of air.
After Anaximenes the earth formed at first, floating in the air. Evaporations made fire and the stars. He found out that solar and lunar eclipses are of physical and not of godly nature. In this theory everything is based on movement and constant change in which nothing can be lost.

After Heraklit of Ephesos (about 544 . 484 BC) the primeval matter is fire because it is the symbol of restlessness and movement. Everything would be becoming and fading, everything would be  “flowing”.
There are two ways:
On the lower way water and earth develop from fire.
On the upper way the vaporizations of the water and the earth lead to tree different things. From bright and pure vaporizations there arises again fire and the stars, from the middle ones the souls and from the dark ones the rain and the meteors. That's how Heraklit tries to explain the change of day and night and of summer and winter. The moon and the sun are spheres that turn their dark sides towards us during eclipses. He devoted most of his attention to the macrocosm. The explosive fire is here the counterpart of the explosion of the primeval atom

Demokrit of Abdera (born about 460 BC)  occupied himself with the microcosm. His world consists of tiny atoms and the empty space in between them. The reality is therefore determined through the “full” and the “empty”.
But the real world does not correspond with the world we can perceive. All things have an expanse but everything is in “movement”. The smallest non – dividable unit of the space things in the atom. The atoms whirl around in space and build up invisible things. After Demokrit there is not only one world but many worlds next to each other that come into being and fade away through great balls of atoms. These balls never arise just by chance, but there is a law in them. Atoms are eternal and indestructible, but they cannot change into each other. There can come nothing from the nothingness or perish into it.

For Platon (427-347 BC) the primeval matter was the dialog between fire, water, air and earth. Her found out that the earth is a sphere that throws its shadow on the moon during lunar eclipses. He also knew that the earth turns around herself and is not the center of the universe.
For Empedokles (born 450 BC) the four elements fire, water, air and earth were the “roots” of all things. These elements don’t have anything in common and cannot connect with each other.
Movement in the elements comes from two opposite forces ”friendship” and “hate”. Friendship connects the roost and hate breaks them apart.
The two pupils of Platon Aristoteles (384 – 322 BC) and Eudoxos (408 – 355 BC) were of the opinion that the earth was surrounded by spheres. The outer spheres with the stars and the spheres in between with the planets rotate with different velocity, while the inner sphere with the four elements always stays in one place. There is jet another element that comes through all the spheres.

Herakleides of Pontos (born about 350 BC) was a pupil of Platon, too. He found out, that the earth turns around itself one time in one day. He was of the opinion that the planets turn around the sun, but the sun was turning around the earth for him.

Aristarch of Samos (ca.310 – 250 BC) in contrary developed a heliocentrical system. For him  all the planets, the earth included turn around the sun.

Hipparchos of Nicäa (about 190 – 125 BC) was against this system, because the planets were not staying on their circular orbits and so their place could not be determined. As a result of this the heliocentrical system was superseded by the system of Aristarch.

Claudius Ptolemäus (about 80 – 170 AC) described a geocentrical system in his main works, the “Almagest” in which all the planets, the moon and the sun were moving on spheres around the earth.