Professor ferrets facts on planets

Benjamin C. Bromley is searching for answers to some of the big questions: How do planets form? How long does it take? How common are Earth-like planets?

Bromley, an associate professor of physics at the University of Utah, is looking not with telescopes that peer into space but with supercomputers that chew through the binary bits and bytes of programs.

He is an expert on computation astrophysics. As his Web page notes www.physics.utah.edu/people/faculty/bromley.html, he focuses on planet formation, formation and evolution of black holes, galactic dynamics and the large-scale structure of the universe. In studying the way planets are made, he is joined by Scott J. Kenyon from the Smithsonian Astrophysical Observatory.

They are simulating the mechanics of how planets develop from the cloud of dust and gas surrounding a young star. They want to discover how quickly planets form and how likely a star is to have rocky planets like Earth.

"This is an important topic to society," Bromley said during a "Science at Breakfast" briefing last week. "Billions of dollars are being committed to finding planets outside the solar system."

Astronomers can't directly observe extrasolar planets. But by measuring the wobble of stars, they can calculate how the gravity of nearby planets tug at these distant suns.

So far, instruments are only sensitive enough to discover huge planets that orbit close to stars. Within the past few years, at least 110 have been detected, and undoubtedly many more will be found as techniques improve.

"Do we have company? Are we alone in the universe?" These questions are at the heart of Bromley's research.

For the past several years, supercomputers at the Jet Propulsion Laboratory, Pasadena, Calif., have been crunching away at codes devised by Kenyon and Bromley.

"We're the only ones that can track everything from dust to the formation of planets," Bromley told the Deseret Morning News.

When small particles collide, often they tend to stick together.

"You have this swarm of different-size planetesimals, little bodies that range from dust all the way up to maybe 100 miles in diameter," he said. "And as the big ones grow, they acquire matter, but they also stir up the smaller bodies."

This is the "runaway" stage of planet formation.

Small particles crashing into each other produce huge amounts of dust, which actually shows up in photos taken of other stars.