Tuesday, March 08, 2005
Some Say the World Was Born In Ice
Here's the theory behind the start of the solar system. In the beginning, some 6 billion years ago, there was blinding light from a nearby supernova. Shockwaves from explosion stirred a large cloud of interstellar gas. The gas collapsed at the cloud's center, igniting the precursor of our Sun (see below Wee Star Found.) Turbulence within the gas cloud gave birth to mile-wide clumps of micron-sized dust, which later grew into planets.
Here's the problem with the scenario. When scientist tried to recreate those conditions, the dust particles bounced "like two billiards balls smacked together." The protoplanets should have never formed.
Now physicists from the U.S. Department of Energy say found an answer to the enigma. The baby planets were held together by cosmic glue made of miniscule grains of sticky ice. Writing the latest issue of the Astrophysical Journal, the scientists say that the dust was "encrusted with molecularly gluey ice" that enabled planets to "bulk up like dirty snowballs quickly enough to overcome the scattering force of solar winds."
James Cowin of the DOE's Pacific Northwest National Lab and leader of the team said that "this ice [was] very different from the stuff we chip off our windows in winter." At extremely low temperatures, between 5-100 Kelvin, the ice spontaneously becomes electrically polarized, pulling the grains together like little bar magnets.
At such low temperatures the ice grains become "fluffy," forming tiny "billiard balls made of Rice Krispies" that barely bounce. Such colliding snowballs would have enough electrical force to stop them from crumbling, as well as enough cushioning to survive the crashes and grow into large lumps, Cowin said.
Today, vestiges of this icy conception remain inside planets like Jupiter, comets, and the far reaches of the solar system.
Cowin "speculates" that similar forces might have been at work during the infancy of hotter inner planets like the Earth, involving silicate dust grains instead of ice.
Here's the problem with the scenario. When scientist tried to recreate those conditions, the dust particles bounced "like two billiards balls smacked together." The protoplanets should have never formed.
Now physicists from the U.S. Department of Energy say found an answer to the enigma. The baby planets were held together by cosmic glue made of miniscule grains of sticky ice. Writing the latest issue of the Astrophysical Journal, the scientists say that the dust was "encrusted with molecularly gluey ice" that enabled planets to "bulk up like dirty snowballs quickly enough to overcome the scattering force of solar winds."
James Cowin of the DOE's Pacific Northwest National Lab and leader of the team said that "this ice [was] very different from the stuff we chip off our windows in winter." At extremely low temperatures, between 5-100 Kelvin, the ice spontaneously becomes electrically polarized, pulling the grains together like little bar magnets.
At such low temperatures the ice grains become "fluffy," forming tiny "billiard balls made of Rice Krispies" that barely bounce. Such colliding snowballs would have enough electrical force to stop them from crumbling, as well as enough cushioning to survive the crashes and grow into large lumps, Cowin said.
Today, vestiges of this icy conception remain inside planets like Jupiter, comets, and the far reaches of the solar system.
Cowin "speculates" that similar forces might have been at work during the infancy of hotter inner planets like the Earth, involving silicate dust grains instead of ice.
