![]() ![]() ![]() That drag-the same force that makes it harder to drive against a headwind-coaxes the grains into clusters that then rapidly collapse into solidity via their own gravity, forming large chunks that glom together to make full-size planets. “It’s one of the best ways we have right now to understand how the planet formation process really gets going,” he says. The behavior of the dust, Youdin says, is akin to how cyclists in a race pack together to minimize drag. Youdin and Goodman called their proposed planet-building mechanism the “streaming instability.” Something else must be guiding the early growth of planets-but what?Ī potential answer to the mystery came about a decade ago, when astrophysicists Andrew Youdin, now at the University of Arizona, and Jeremy Goodman of Princeton University discovered whirling grains of dust dragging against gas in a disk can form the seeds of planets. But that process peters out at larger scales, where bigger objects bounce or shatter rather than sticking together when they collide. Electrostatic forces would build pebble-size clumps, similar to how dust bunnies form under a couch. ![]() But exactly how dust particles stick together had long perplexed scientists. Grains of rock and minerals in the disk somehow clump together and eventually grow into an entire world. You start with a disk of gas and dust swirling around a newborn star. ![]()
0 Comments
Leave a Reply. |