Turbulence Key to Planet Formation, New Study Suggests

September 4, 2007

Swirling eddies and chaotic vortices are crucial to the formation of new planets, suggests a counterintuitive new study.

Such turbulence is vital to helping planets go from "toddler" to "teenage" size by helping rocks and boulders stick together, the computer simulation hints.

This is a turnaround from several years ago, when scientists considered turbulence a destructive bugaboo for newly forming planets.

A few scientists recently suspected that turbulence might help in planet formation, but no one had showed in detail how that might work until now.

"We were the first to model how interacting boulders move around in this turbulence," said Anders Johansen of the Max Planck Institute for Astronomy in Germany, who led the research team that made the new findings. The study appeared last week in the journal Nature.

The research showed that turbulence could create "planetesimals," or planetary precursors, very quickly—in only seven orbits around a star, or around just a hundred years.

Collision Conundrum

New solar systems form from a swirling disk of dust and gas surrounding a central star. (Related: "Planet-Forming Disk Spotted Around Dead Star" [April 5, 2006].)

As the matter swirls around, microscopic bits of dust hit each other and stick together. Gradually they can gather into rocks and boulders, around a yard (a meter) across.

"We have a pretty good grasp of this [process]," Johansen said.

But explaining how matter forms bigger clumps—up to planetesimals about a kilometer across—has eluded scientists.

"That has been known to be a big problem for the last 30 years," Johansen said.

Continued on Next Page >>


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