Cosmological simulations include dozens of prescriptions to describe the 13.8-billion-year evolution of the Universe, including numerical recipes for dark energy (so-called lambda), weakly interacting cold dark matter, gas accretion onto primordial galaxies, star formation and evolution, and feedback from quasars and supernovae. The outcome of these lambda cold dark matter simulations reproduce many of the observed features of the real universe. However, the models predict that dozens of small dwarf satellite galaxies should orbit medium-sized galaxies like our Milky Way and Andromeda in random orientations, but new research suggests most satellite galaxies orbit their host galaxies aligned along a single plane.
An international team of researchers have considered the late Stephen Hawking’s 1974 theory of the existence of primordial black holes, born shortly after the Big Bang, and his speculation that they could make up a large fraction of the elusive dark matter scientists are trying to discover today.
A long time ago gravity drew two galaxies together into the gorgeously chaotic state we see above with NGC 6052. Stars from within both of the original galaxies now follow new trajectories caused by the new gravitational effects.