BEIJING, Aug. 8 (Xinhuanet) -- Planetary formation in the first few million years is a violent tug of war with planets fighting to feed on gas and dust while tugging at each other with gravitational arms.

    "There's massive bodies competing with each other and flinging each other around," said Edward Thommes, a physicist at the University of Guelph in Ontario, Canada, and lead author of the new research published in Thursday's journal Science.

    The simulation traces the creation of a planetary system from almost beginning to end, for the first time, and suggests that our solar system started with just the right mass to become a relatively orderly place in the universe.

    "You have to have the conditions just right," Thommes added, "They have to be in a fairly narrow range."

    Thommes and his colleagues at Northwestern University ran the simulation through over 100 scenarios to see how gas giants formed from the gas disks that surrounded young stars. Newborn planets typically seemed to get pushed toward the central star by the gas disk remnant surrounding them, they found.

    The simulated planetary systems mostly line up with observations of more than 300 exoplanets discovered so far. But the observed exoplanets represent those that are relatively easiest to find, or "a filtered sample" of what astronomers can see, Thommes cautioned.

    The researchers chose to sacrifice some detail in their simulation in order to model planetary systems from start to finish. They hope to extend their hybrid model approach so that they can eventually model planets spiraling all the way into the central star.

    Currently, the simulation cannot track such planets beyond a certain point.

    (Agencies)