galaxies Avishai Dekel (1951–) studied galaxy formation and large scale structure in dark matter-dark energy dominated universes Robert H. Dicke (1916–1997) measured background radiation, used an early version of the anthropic principle to relate the gravitational constant to the age of the universe Mike J. Disney (1937–) discovered low surface brightness galaxies E George Efstathiou (Cosmologist) (1955–) pioneering computer simulations, observations of galaxy clustering and studies of the fluctuations in the cosmic microwave background Jürgen Ehlers (1929–2008) described gravitational lensing and studied the mathematical implications of an isotropic microwave background Jaan Einasto (1929–) studied structure in the large-scale distribution of superclusters of galaxies, early proponent of dark matter Albert Einstein (1879–1955) introduced general relativity and the cosmological constant George F. R. Ellis (1939–) theorized a cylindrical steady-state universe with a naked singularity as recycling mechanism Richard S. Ellis (1950–) used gravitational lensing and high-redshift supernovae to study the origin of galaxies, large scale structure, and dark matter F Sandra M. Faber (1944–) discovered the Great Attractor, a supercluster-scale gravitational anomaly; co-inventor of the theory of cold dark matter Hume A. Feldman (1953–) studies cosmological perturbations and the statistical and dynamical properties of the large scale structure of the universe Pedro G. Ferreira (1968–) his main interests are in general relativity and theoretical cosmology Carlos S. Frenk (1951–) studied cosmic structure formation Alexander Friedmann (1888–1925) discovered the expanding-universe solution to general relativity G George Gamow (1904–1968) argued that observed proportions of hydrogen and helium in the universe could be explained by the big bang model, modeled the mass and radius of primordial galaxies Margaret J. Geller (1947–) discovered the Great Wall, a superstructure-scale filament of galaxies Thomas Gold (1920–2004) proposed the steady-state theory Gerson Goldhaber (1924–2010) used supernova observations to measure the energy density of the universe J. Richard Gott (1947–) proposed the use of cosmic strings for time travel Alan Guth (1947–) explained the isotropy of the universe by theorizing a phase of exponential inflation soon after the big bang H Stephen W. Hawking (1942–2018) described singularities in general relativity and developed singularity-free models of the big bang; predicted primordial black holes Charles W. Hellaby described models of general relativity with nonconstant metric signature Michał Heller (1936–) researched noncommutative approaches to quantum gravity Robert C. Herman (1914–1997) predicted the background radiation temperature Lars Hernquist (1954–) studied galaxy formation and evolution Chris Hirata (1982–) researched weak gravitational lensing Honorius Augustodunensis (c.1080−1151)