International Journal of Physics and Astronomy, Vol. 1 No. 1, December 2013 35 ©American Research Institute for Policy Development www.aripd.org/ijpa The Cosmological Theories of the Atomic Philosopher, the forerunner of Quantum Physics, Astrophysics and Cosmology Konstantinos Kalachanis 1 Evangelia Panou 1 Efstratios Theodossiou 1 Abstract The aim of the present work is the study of Leucippus’ and Democritus’ cosmological theories for the atoms, the vacuum and the creation of worlds comparing to the principles of Quantum Physics, Astrophysics and to cosmological theories of modern Cosmology. Keywords:atoms,vacuum, quantum physics, inflation, Democritus. 1. Introduction In ancient Greek world, philosophy and scientific research were mainly affected by the Pre- Socratic philosophers, who searched for the origin of the world. The Pre-Socratic natural philosophers studied the nature mechanisms so as to determine the causes of the natural phenomena, making thereby cosmology an integral part of philosophy. The cosmological search of the Greek philosophers pointed to determining the primary substance that the world was created from. Many ancient philosophers asserted that a First Principle created the world; Thales of Miletus called this first principle water, Anaximenes air, Anaximander apeiron (boundless) and Heraclitus fire respectively. Other philosophers argued that the First Principle was not unique and there were more than one principle; Anaxagoras called the ultimate principles of things Cosmic mind (Nous) and claimed the existence of infinite material substances called homeomerias. The Pythagoreans believed that the universe was formed by the harmonies consisted from numbers and governed by mathematical relations. However, the Atomic philosophers of the 5th century played the most decisive role in indentifying the first principle of the world. The philosophers Leucippus and Democritus argued that atoms were the basic units of all the things of the world. As a result, the fundamental principles of the modern Atomic Theory, which played a crucial role in the research field of Cosmology, had already been set. 2. The Atoms, the Vacuum and Modern Physics Research Leucippus and Democritus innovated with respect to the other Pre-Socratic philosophers and proposed a new philosophically theory. They did not believe that fire, air, water or land were the ultimate substances of the world, but the atoms and the void or in other words the being and the non- being respectively. The being is full and solid; not being is empty and sparse. Ιt is said that the vacuum exists as long as the body exists; thus the non-being exists as long as the being exists. These two are the material causes of the existence of the things (Aristotle, Metaphysics, 985, b 4-10). In addition, the vacuum is characterized as meden or ouden which in ancient Greek means nothing. 1 Department of Astrophysics-Astronomy and Mechanics, School of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, Zographos 157 84, Athens, Greece.