Sim Zoom (video) Durham University Share Print E-Mail Loading video... Caption Simulations of the formation of a group of galaxies in an expanding universe, featuring no cosmological constant (left) and a very large cosmological constant (right). In the color scheme, lighter colors represent denser parts of the universe, when gravity is drawing matter together into galaxies. The simulation runs for 15 billion years. Without a cosmological constant (left), matter comes together under the attractive force of gravity into smaller galaxies, which combine into a large galaxy. With a large cosmological constant (right), the faster expansion of the universe stops matter from grouping together, and galaxies fail to form. Credit Luke A. Barnes, Pascal J. Elahi, Jaime Salcido, Richard G. Bower, Geraint F. Lewis/EAGLE Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.