Earth`s most powerful telescope strengthens Big Bang theory
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Last Updated: Friday, June 07, 2013, 10:37
  
Washington: Scientists using the most powerful telescope on Earth has discovered that the moments just after the Big Bang happened more like the theory predicts, eliminating a significant discrepancy that troubled physicists for two decades.

One of the most important problems in physics and astronomy was the inconsistency between the lithium isotopes previously observed in the oldest stars in our galaxy, which suggested levels about two hundred times more Li-6 and about three to five time less Li-7 than Big Bang nucleosynthesis predicts.

This serious problem in our understanding of the early universe has invoked exotic physics and fruitless searches for pre-galactic production sources to reconcile the differences.

The team, led by Karin Lind of the University of Cambridge, has proven that the decades-old inventory relied on lower-quality observational data with analysis using several simplifications that resulted in spurious detections of lithium isotopes.

Using observations of ancient stars with W. M. Keck Observatory's 10-meter telescope and state-of-the-art models of their atmospheres has shown that there is no conflict between their lithium-6 and lithium-7 content and predictions of the standard theory of Big Bang nucleosynthesis, restoring thus the order in our theory of the early universe.

The discovery that the universe was expanding by Edwin Hubble in the 1920s and subsequent observations suggest the universe began about 13.8 billion years ago in an event called the Big Bang. The fundamental observations that corroborate the Big Bang are the cosmic microwave radiation and the chemical abundances of the light elements described in the Big Bang nucleosynthesis theory.

"The predictions of Big Bang nucleosynthesis have been one of the main successes of the standard Big Bang model," said lead author Lind.

"Our findings remove much of the stark tension between 6Li and 7Li abundances in stars and standard BBN, even opening up the door for a full reconciliation. This further consolidates a model resting heavily on the pillars of the cosmic microwave background and the expanding universe," the researcher added.

Taking accurate measurements of lithium-6 and lithium-7 in old stars is extremely challenging, both from a theoretical and observational perspective, in particular for lithium-6, because being the less abundant isotope of lithium, its signature is very weak.

The required data can only be obtained with the largest telescopes on Earth such as the Keck Observatory on the summit of Mauna Kea, Hawaii equipped with the powerful High Resolution Echelle Spectrometer (HIRES) spectrograph to disperse the stellar light into its constituent colours and absorption features.

The discovery will be published in the international journal Astronomy Astrophysics.

ANI


First Published: Friday, June 07, 2013, 10:37


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