Saturday, April 28, 2012

Big Bang: Hydrogen, Helium, Lithium

Wikipedia explains in its clear, concise and comprehensible way

According to modern cosmological theory, lithium—as both of its stable isotopes lithium-6 and lithium-7—was among the 3 elements synthesized in the Big Bang.

Though the amount of lithium generated in Big Bang nucleosynthesis is dependent upon the number of photons per baryon, for accepted values the lithium abundance can be calculated, and there is a "cosmological lithium discrepancy" in the Universe: older stars seem to have less lithium than they should, and some younger stars have far more.

The lack of lithium in older stars is apparently caused by the "mixing" of lithium into the interior of stars, where it is destroyed.

Furthermore, lithium is produced in younger stars.

Though it transmutes into two atoms of helium due to collision with a proton at temperatures above 2.4 million degrees Celsius (most stars easily attain this temperature in their interiors), lithium is more abundant than predicted in later-generation stars, for causes not yet completely understood

Though it was one of the three first elements (together with helium and hydrogen) to be synthesized in the Big Bang, lithium, together with beryllium and boron are markedly less abundant than other nearby elements. This is a result of
the low temperature necessary to destroy lithium, and
a lack of common processes to produce it

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