Although it has recently become increasingly popular to attribute the iso-topic anomalies observed in meteorites to the result of inhomogeneous mixing of exotic substances from outside of the solar system over a short time, rather than the result of free decay, existing experimental data can be explained in a straightforward manner as due to the result of free decay of the extinct radionuclides created by the nucleosynthesis processes which took place in a supernova more than 5 billion years ago. The aluminum isotope data for the SiC and graphite grains of the Murchison meteorite and the Ca-Al-rich Allende inclusions tell us that these inclusions formed (10.3 ± 0.5) million years after the explosion of a supernova, while the iodine isotope data indicate that the Ca-Al-rich Allende inclusions began to form (12 ± 1) million years after the explosion of a supernova.
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