Solar Systems Like Ours Uncommon, U of G Study Finds

August 08, 2008 - News Release

An orderly solar system like our own is a rare occurrence, happening only under peaceful conditions, according to new research by a University of Guelph physicist.

Ed Thommes developed a new computer modeling method that simulates the birth of planetary systems. His research was published today in the prestigious journal Science, published by the American Association for the Advancement of Science. The research is making headlines around the world. Read the articles
Watch a video of Thommes discussing the findings

The study, conducted with Frederic Rasio and Soko Matsumura from Northwestern University in Illinois, found that planets of varying masses and orbits can move around one another and their parent star in different ways.

"Whatever possibility of a planetary system we can think of probably exists out there somewhere," said Thommes, the co-author of 20 research papers about planets and planetary systems.

"Nature really does throw the dice in all directions."

But a solar system like ours is uncommon, he said. Planetary systems with equivalents to Jupiter and Saturn – two gas giants moving in near-circles and practically unchanged since birth – pop out rarely in their simulations.

Most often, solar systems harbour unruly gas giants whose eccentric orbits make life unpredictable and even deadly for nearby bodies, he said.

But in our solar system, Jupiter and Saturn may help "keep the peace" by acting like bouncers to intercept unwelcome comet visitors before they near the inner planets.

Most scientists believe that solar systems form when gas in giant disks surrounding a star begins to collect into dust. Like a growing snowball, that dust attracts more material and eventually becomes planets, moons, comets, asteroids and other celestial bodies.

Much of the process is still a mystery. "It's embarrassing but we still don't understand how we get from dust bunnies to big boulders," said Thommes.

Scientists model the process using powerful computer simulations.But unlike earlier attempts that looked only at parts of that process, Thommes and his collaborators simplified the model to cover the entire path from a gas disk to gas giants such as Jupiter or Saturn.

They found that gas giants form within 1 to 10 million years, a blip measured against the age of our solar system (4.5 billion years old).

Learning more about the effects of larger planetary neighbours may help us understand how a habitable Earth-like planet can develop and thrive, he said.

The Guelph physicist said their model offers a faster and easier method to investigate the formation of other planetary systems. Within the past decade, astronomers have found more than 300 exo-planets orbiting nearby stars, including 29 systems containing more than one planet.

Ed Thommes
Department of Physics
519 824-4120, Ext. 53034

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