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No, the conditions for formation aren't right. Wikipedia has a good summary. Here's an excerpt:

Most meteorites that fall on Earth are chondrites, which are characterized by the presence of round grains called chondrules (from Greek chondros, grain). Chondrules formed as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites represent the oldest solid material within our solar system and are believed to be the building blocks of the planetary system.

Formation
Chondrules are formed by a rapid heating (within minutes or less) of solid precursor material to temperatures between 1500°C and 1900°C and subsequent melting. This is followed by a cooling within one to several hours (Wood, 1999). However, the environmental setting, the energy source for the heating, and the precursor material are not known. The solar nebula or a protoplanetary environment are possible places of formation.

Proposed energy sources are:

Impact melting
Meteor ablation
Hot inner nebula
FU Orionis outburst of the early sun
Energetic bipolar-shaped outflows
Nebular lightning
Magnetic flares
Accretion shocks
Nebular shocks
Supernova radiation and shockwave
Isotope studies indicate a nearby supernova explosion added fresh material to what became our solar system. The Ningqiang carbonaceous chondrite contained sulfur-36 derived from chlorine-36. As chlorine-36 has a half-life of only 300,000 years, it could not have travelled far from its origin. The presence of iron-60 also indicates a nearby supernova. Such proximity implies the radiation and shockwave would have been significant, although the degree of heating is not known.

In contrast, the fine grained matrix, in which the chondrules are embedded after their accretion into the chondrites parent body, is assumed to have been condensed directly from the solar nebula.

2007-03-03 18:07:03 · answer #1 · answered by GatorGal 4 · 0 0

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