Extra-Solar Planetary Systems Simulation (IMAGE) U.S. National Science Foundation Caption This depiction shows the range of computer simulations used to explore the formation of extra-solar planetary systems. It shows a planet-forming circumstellar disk (the star is in the center) seen at a very highly inclined angle (close to edge-on) in three different starting condition scenarios (left to right). From top to bottom are snapshots of the system at three intervals between the start of the universe and 500 million years of evolution, at which point the disk makes planets and is cleared out of material. At left is, "Typical disk which grows gas giants," in which the initial disk mass is high but the viscosity (stickiness) of the disk material is low. This system forms planets early and often, with lots of migration of these planets towards to the central star (where they are destroyed). Big gas giants (similar to Jupiter) are formed in the inner planetary system (where the Earth lives in our solar system). This model closely mimics the types of planetary systems seen today outside our solar system. At right is, "Typical disk which does not grow gas giants," the case in which the disk mass is low but the viscosity is high. In this case, planet formation is too slow to allow big gas giants to form before the disk is gone. In the middle is the rare case in between these two extremes in which big gas giants form, but do not migrate to the inner planetary system, and the orbits of all of the planets in the system are circular and stable. This is like our solar system, but it is one of the uncommon results of the simulations. Credit Ed Thommes, University of Guelph, Canada Usage Restrictions None License Licensed content 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.