Cosmologist who explored the clustering of galaxies as a way of establishing the distribution of dark matter in the universe
Between 1984 and 1992 the cosmologist Nick Kaiser, who has died of heart failure aged 68, created many of the ideas now used by astronomers to map the large-scale distribution of dark matter in the universe. His analysis of the clustering of galaxies and the distortion of galaxy shapes by gravitational light deflection are at the heart of the leading modern cosmological experiments, particularly the recently launched Euclid satellite.
Kaiser’s research concentrated on the large-scale structure of the universe. Galaxies such as our own, the Milky Way, are congregated in a vast pattern of density fluctuations – superclusters that extend for at least 100m light years. All this structure probably represents the relic of primordial fluctuations that collapsed under their own gravity, generating galaxies and the stars and planets within them. We see these patterns in the clustering of the galaxy distribution, but much evidence tells us that the galaxies are embedded in invisible underlying dark matter, which dominates the gravity – dragging gas with it, which in turn forms into the stars of the visible galaxies.
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