Modern Theoretical and Observational Cosmology

Manolis Plionis & Spiros Cotsakis plionis@sapfo. astro. noa. gr skot@aegean. gr Since the dawn of human civilisation natural phenomena have been subject to observation and investigation by the humans who initially ascribed to them 'divine' powers. Gods of 'good' and 'evil' werecreatedaccording to the useful ness or notofsuch unexplained, atthetime, phenomena. Astheir understanding of the world developed and deepened, the divine powers, religious beliefs, su perstitions and mysticism gave their place to the knowledge, limited that it may be, of physical reality. However, many issues have been and still are out of grasp of human understanding. These issues have always been at the center of philosophical, theological, and more recently, scientific debate. It is to us incredible that many of the conclusions concerning the true scientific explanation of the external world, to which the ancient Greeks arrived purely on the basis of abstract thought, came so near to modem scientific ideas and also form the basis of modem science. We cannot but stand with amazement at the original thoughts of Archimedes who, among his many extraordinary achieve ments in mathematics and physics, calculated (cf. TheSandReckoner) the mass density of the observable universe and came up with a figure that is in complete agreement with current estimates coming from observational cosmology.

Zusammenfassung
Proceedings of the second Hellenic Cosmology Meeting, held in the National Observatory of Athens (Penteli, 19-20 April 2001)

Inhalt
Theoretical Cosmology.- Current Trends in Mathematical Cosmology.- Casimir Effect Contribution to the Cosmological Constant.- Masses of Cosmological Structures.- Geometrical Aspects of Cosmic Magnetic Fields.- Galactic Magnetic Fields as a consequence of Inflation.- Relaxation of the Cosmological Principle.- A Note on Wavemap-Tensor Cosmologies.- Inflation in String Theory and how you can get out of it.- Quantum Cosmology for the General Bianchi Vacuum Geometries.- Black Hole Entropy, Topological Entropy, Baum-Connes Conjecture.- Observational Cosmology.- Froth across the Universe.- Cosmological Parameters.- Forming Counterrotating Galaxies.- Cosmological Parameters from the Clustering of AGN.- Large-Scale Environmental Effects of the Cluster Distribution.- Scale Dependence of Dark Energy Antigravity.- Probing the Evolution of Galaxies using Redshifted H? Emission.- Gas in the Universe.- Summary.- Report to Anaximander.