Mr President, etc
It is a great pleasure for me, representing the selection committee for the 2013 Nemitsas prize in physics, to shortly explain to you the reason for our decision to award the prize to Professor George Efstathiou. The committee was formed by Professor Brian Schmidt from the Australian National University, Professor Dimitri Nanopoulos from Texas A& M and myself. Although we had to select one from a number of internationally recognized physicists of Cypriot origin, all having impressive research records, the task was in the end not so difficult, since we had all, independently, chosen Professor Efstathiou as the fore runner. My area of specialization is quite different from Professor Efstathiou’s, but even a cursory review of his scientific achievements made it clear to me that he is not only an excellent scientist, but that he in fact belongs to the much smaller group of people who define areas of research rather than merely contributing to them. Walking down the corridor to speak to my colleagues in the astroparticle and cosmology groups, this impression was strongly reenforced, and it was confirmed by my fellow members of the committee, one of which is in fact an expert in the field of cosmology.

Professor Efstathiou’s scientific achievements are also reflected in his career path, and the position he holds in the academic community. He studied at the university of Oxford and got his Ph.D. in astronomy at Durham University in 1979. After graduating, he was a postdoc at UC Berkeley, and then held a research fellowships at Cambridge, UK, from 1980 to 1988, when he, at the age of 33, was appointed Savilian Professor of Astronomy at the University of Oxford. He returned to Cambridge in 1997 as Professor of Astrophysics and was the director of the Institute of Astronomy between 2004 and in 2008, when he became the first director of the Kavli Institute for Cosmology. This Kavli institute is a worlds leading center in its area. Professor Efstathiou has received several prestigious rewards in prior to this one, and I should especially mention the 2011 Gruber Cosmology Prize.

You might be somewhat surprised by a physics prize being awarded to someone with a background as a professor in astronomy, and you might wonder what is astrophysics, and what is cosmology? By spending a couple of minutes telling you, from a non-expert position, about professor Efstathiou’s research, this might become more clear to you. Astronomers traditionally make maps of the sky. First they were just looking at it, sorting stars in constellations and giving them names. Later, using more and more powerful telescopes, they discovered that the stars we see with our bare eye are only a tiny tiny fraction of all stars. Most of them reside in far away galaxies of various shapes, and these galaxies are themselves organized in even larger structures, clusters and superclusters of galaxies. With the notion of the Big Bang, that is the idea that all stars and planets emerged from a large primordial explosion, where the very time and space was created, scientists could finally start to ask precise questions about the creation of our universe. Why does the universe look the way it does? What makes stars come together in galaxies, and galaxies to form clusters, and what characterizes the distribution of galaxies and clusters of galaxies? It was this kind of questions that led Professor Efstathiou to develop computer programs that were powerful enough to actually simulate the evolution of the universe. And what he, and his collaborators, concluded at the late 1980ies was

thoroughly revolutionary – the observed distribution of shining stars cannot be understood without assuming that there is another form of matter – cold dark mater – and that the total weight of this matter is about five times the combined mass of all the stars.We still do not know what the cold dark matter is made of, but the search is on in many laboratories around the world. It is a beautiful illustration of the unity of physics, that the laboratory at CERN, which studies the smallest constituents of matter, and of recent fame for its discovery of the Higgs particle, is also looking for the cold dark matter that Professor Efstathiou introduced to explain the largest observed structures in the universe. But Professor Efstathiou’s calculations pointed in an even more astonishing direction. Just assuming the existence of cold dark matter, was not enough for the simulations to agree with observations. Something more was needed, namely what is now referred to as dark energy. The dark energy, which contributes about seventy percent or the energy content of the universe cannot be underwood as ordinary particles, but later observations on exploding stars, called supernovae, and the nature of the cosmic microwave background radiation, are in line with the early results of Professor Efstathiou and strongly supports the existence of dark energy. The microwave background radiation has survived since a time when the universe was still young. Just as the color of a heated piece of metal reveals its temperature, so that changes in its color tells us that it is not uniformly heated, changes in the color, that is the wave length, of the background radiation tells us how uniform the young universe was. Professor Efstathiou has played a central role in the collaboration behind the Planck satellite, which this year presented the so far best measurement of the background radiation, and these measurements have allowed for a very precise determination of the amount of cold dark matter and dark energy. Planck is continuing to take data, and Professor Efstathiou will for sure continue his work to unravel the secrets of the creation of the universe. With this I will end, and just read you the official prize citation:

“Professor George Efstathiou is known for his pioneering use of computer simulations of structure formation in the Universe, for surveys of large-scale structure in the Universe, and for theoretical and observational investigations of the cosmic background radiation, including leadership roles in the Planck satellite. Efstathiou’s seminal advances have shaped our understanding of the Universe and have strongly contributed to the standard model of cosmology.”