June 6, 2013
New Insights Into Big Bang From Keck Observatory
John P. Millis, PhD for redOrbit.com — Your Universe Online
The big bang theory is the leading theory to explain the origin of the Universe. While challengers exist, no other well-developed theory has substantiated itself as a serious contender. But this does not mean that the big bang is without its problems.
One issue that has plagued our origins story is the relative abundance of lithium isotopes Li-6 and Li-7 in the oldest observed stars. These atoms would have been constructed early in the development of the Universe during the big bang nucleosynthesis — when the first elements of the Universe were formed.
Previous studies of old stars indicated that these isotopes existed in amounts far greater than the big bang predicts. New data from the High Resolution Echelle Spectrometer (HIRES) has allowed researchers to conduct a more accurate study of the Universe´s oldest stars.
“Back in 2004 HIRES was upgraded with CCDs having smaller pixels, allowing researchers to see finer details in the spectrum,” University of Sao Paulo´s Jorge MelÃ©ndez said. “A high spectral resolution provided by HIRES is needed to study with exquisite detail the line profile and to estimate the presence of Lithium-6. The large light-collecting power of Keck Observatory allowed us to observe stars with a more ℠pristine´ composition than any previous study.”
The results indicate that the abundances of the lithium isotopes is in line with predictions made by the big bang, laying to rest the controversy that has spanned decades.
“The predictions of Big Bang nucleosynthesis [BBN] have been one of the main successes of the standard Big Bang model,” noted Karin Lind, from Cambridge University and lead author of the study. “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.”
“Understanding the birth of our Universe is pivotal for the understanding of the later formation of all its constituents, ourselves included,” Lind said. “The Big Bang model sets the initial conditions for structure formation and explains our presence in an expanding universe dominated by dark matter and energy.”