14 December 2009
Scientists know that the Sun and planets of our solar system formed billions of years ago from a vast disk of gas, dust, and rock. Over time, this disk collapsed under the weight of its own gravity to form our local star, planets, and home: Earth. Speakers during today’s P12B: Early Solar System talks painted a complex and surprising picture of our solar system’s ancient era.
In one presention, geologist Katherine Bermingham of the Institut fuer Mineralogie in Munster, Germany contradicted a fundamental assumption about the dusty disk: that it was an identical rocky field uniform in composition. Her data about barium isotopes suggests that the early solar system was a chemically varied locale, which means radioactive dating techniques would need to account for local ratios of isotopes.
In another startling result, Audrey Bouvier from Arizona State University pushed back the age of the solar system by a million and a half years. By looking at lead isotopes ratios, she and her team gave higher precision measurements of the solar system’s age than ever before. They make previous measurements more internally consistent and will help with future data interpretations.
Shigenobu Hirose of JAMSTEC in Yokohama, Japan presented a model of turbulence in the early disk, suggesting that it was a hot, chaotic place. His mathematical simulations uncovered the dynamics of planets coalescing from the rocks, showing how turbulent pockets heated and cooled through time. The behavior is not unlike that of a planetary atmosphere.
Rounding out the discussion of planetary formation was Olenka Hubickyj from NASA Ames Research Center, who showed that Mars-sized objects served as seeds that accreted dust and grew to a Jupiter-type giants. Her models are the first to accurately simulate the “run-away” period of giant planet formation, where the proto-Jupiter quickly gobbles up all the nearby gas to fatten itself. These findings offer a much more realistic scenario than previously obtained.
-Adam Mann, UC Santa Cruz Science Communication Graduate Student