"Scientists are shedding light on the mysterious origins of ancient meteorite grains using a new analysis method. These grains, which are older than the solar system itself, formed in ancient stars that died before our sun's birth. Similar stars still exist in the universe and the analysis of these presolar grains provides an interesting glimpse into the stars' chemistry...In the Murchinson meteorite, grains of rock older than the solar system are embedded in younger material. Scientists know from previous research that these grains pre-date the birth of the solar system because their chemical composition is different. "These grains are made of silicon carbide, that is silicon and carbon atoms," Liu said. "But silicon carbide doesn't naturally form in our solar system because we have a lot of oxygen around and all these carbon atoms would bond with oxygen first to form carbon oxide molecules."
My observation. The ability to clearly identify the presolar grains looks challenging and a model for the early, protoplanetary disk composition is required too. Meteorites orbiting in the main asteroid belt can complete more than 227 million revolutions around the Sun in one billion year time span using the heliocentric solar system model. Do we have a published cosmic ray exposure age for the Muchinson meteorite? What does the CRE age show relative to the radiometric age(s) accepted and would the CRE age place time constraints on how long Murchinson moved around the Sun?
We also have a new report out today challenging how s-process and r-process explanations were developed and used to explain some of Earth's chemistry.
Challenging the big bang puzzle of heavy elements (phys.org)
Earth factories: Creation of the elements from nuclear transmutation in Earth’s lower mantle: AIP Advances: Vol 11, No 10 (scitation.org)
"ABSTRACT Stellar nucleosynthesis is a widely acknowledged theory for the formation of all elements in our universe; traditionally, we say that the highest mass stars transmuted lighter elements into heavier elements lighter than iron. Here, we propose that the formation of 25 elements with smaller atomic numbers than iron resulted from an endothermic nuclear transformation of two nuclei confined in the natural compound lattice core of the Earth’s lower mantle at high temperatures and pressures..."
This new model will likely cause problems for initial chemistry of the protoplanetary disk that the solar system is postulated to evolve from.
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