August 9, 2006
Mystery of missing lithium solved- scientists
LONDON (Reuters) - The case of the lithium that has gone missing since the Big Bang has been solved -- the stars swallowed it, scientists said on Wednesday.
The discrepancy between the quantity of lithium estimated to have been created at the start of the universe and the small amount now actually found has long perplexed astronomers, bringing into question fundamental planetary theory.Scientific theory said that up to three times the amount of lithium -- the lightest of the solid elements -- was produced along with the main elements hydrogen and helium in the Big Bang than can now be found in the older stars.
But now a team led by Andreas Korn from the Uppsala Astronomical Observatory in Sweden say they may have finally solved the riddle.
Writing in the science journal Nature they said that whereas other elements were hurled back into the atmosphere by convection, lithium was dragged down into the star where it was destroyed when temperatures rose over 2 million degrees.
Based on observations of 18 stars of different ages, the team calculated that the original lithium content was 78 percent higher than that currently found -- enough to account for the discrepancy with Big Bang estimates.
"We thus conclude that diffusion is predominantly responsible for the low apparent stellar lithium abundance in the atmospheres of old stars by transporting the lithium deep into the star," they wrote.