2002 Annual Science Report
University of Washington Reporting | JUL 2001 – JUN 2002
Delivery of Organic Materials to Earth and Earth-Like Planets
We are investigating the present delivery of organic materials by the 40,000 tons comet and asteroid particles (< 1 millimeter diameter) that annually impact Earth. We will relate the results of this work to: A) the general delivery of organics to the pre-biotic earth when the flux of such particles was orders of magnitude higher and B) the general delivery of organics in interplanetary dust to habitable zone planets in all planetary systems.
Our recent work has focused on the role of 10µm and 200µm particles as carriers of organic material to the early earth. We are studying the 10µm cometary and asteroidal particles collected from the stratosphere and 50-300µm extraterrestrial particles collected from the 140mx25mx25m volume of ice melted to provide water for the South Pole station. We are employing a variety of techniques to characterize the organic contents and compare the small particles with those of 200µm size that dominate the Earth's mass accretion of extraterrestrial material. We have placed particular emphasis on the role of atmospheric entry heating in modifying the organic materials, and we have built a special oven to simulate the effects of hypervelocity entry. From the collected particles and laboratory heating experiments, we see that the organics in small particles meet three fates: A) survival with only moderate alteration, B) sublimation into the atmosphere and C) conversion to refractory char (similar activated carbon). All three of these forms must have been abundant on the pre-biotic earth and could have played critical roles in the evolution of life.
PROJECT MEMBERS:Donald Brownlee
RELATED OBJECTIVES:Objective 11.0
Determine (theoretically and empirically) the ultimate outcome of the planet-forming process around other stars, especially the habitable ones.