Did science develop differently in different ancient civilisations, and if so, why? This article compares the development of medicine, mathematics and astronomy in ancient Greece and ancient China. It identifies certain significant differences in the way in which the problems were formulated and the aims and methods used to resolve them, and it relates these to the social institutions and values of the society within which the scientists work.

Present understanding suggests that a doubling of CO2 emission will occur in about 50 years and will lead to global warming of 2–4°C. Data from the past supports this. The paper analyses the factors influencing climatic change and the challenges to humanity this presents.

The paper describes very briefly the development of theoretical accounts of the system of the world from Antiquity to Kepler. It shows how all the three great scientific traditions—the Aristotelian, the Platonic and the Archimedean—have been active throughout this history. There is no single ‘scientific’ approach to the phenomena of nature.

The recognition of the heliocentric motion of planets led to the geometrical determination, by Copernicus and Kepler, of the relative planetary distances. Completed by the determination of the true distance from the Earth to the Sun, by geometrical methods, this gave the total scale of distances in the planetary realm. In the years 1830–1840, the same geometrical methods could be applied to stars, the angular resolving power of telescopes having then greatly improved. This established the stellar world up to some hundreds of light-years, with well-determined distances. To go beyond, to the distant stars and to the galaxies, indirect methods were used, allowing a rather accurate gauge of the depths of the universe, up to some billions of light years. The penetration in depth leads naturally to the penetration back in time. The problem of timescales in the universe is one which is still debated, as the cosmologies presently available still contain many assumptions about the very notion of time. Neither the horizons nor the origins are yet within reach; we are merely extrapolating what is known; it is no longer pure astrophysics, but close to metaphysics.

The discovery of complex structures in the universe is summarized and commented upon. The strong linkage between improved observing techniques, taxonomy and early studies of evolution is illustrated. Comments are also made on the growing modern interest in morphology and the origin of structures in astronomy.

During the last 25 years, evidence has accumulated that our universe has evolved, over a period of 10–15 billion years, from a hot dense fireball to its present state. Telescopes can detect objects so far away that the universe had only a tenth its present age when the light we now receive set out towards us. The cosmic background radiation, and the abundances of elements such as helium and lithium, permit quantitative inferences about what the universe was like when it had been expanding for only a few seconds. The laws of physics established in the laboratory apparently suffice for interpreting all astronomical phenomena back to that time. In the initial instants of cosmic expansion, however, the particle energies and densities were so extreme that terrestrial experiments offer no firm guidance. We will not understand why the universe contains the observed ‘mix’ of matter and radiation, nor why it is expanding in the observed fashion, without further progress in fundamental physics.

The Big Bang theory requires all matter and galaxies to have been created simultaneously 15 billion years ago. But many young galaxies have been observed which must have been created more recently. Moreover, these younger objects, although demonstrably nearby, have large redshifts which cannot be due to recession velocity in an expanding universe. The fundamental assumption in the Big Bang is that extragalactic redshifts are caused only by the velocity of recession. It is shown here how every observational test which can be made on galaxies, and even stars, contradicts the assumption. It is described how a more general and more correct solution of the Einstein general relativity equations yields a non-expanding, continuous creation universe of unlimited age and size.