Like a carnival barker, the news media touts the exploits of NASA. One of the latest sideshows deals with NASA's claim to have calculated the precise age of the universe. What the news media fails to tell you are the underlying problems with NASA's cosmological age calculations.
A key component when evaluating the age of the universe is the Cosmic Microwave Background (CMB) radiation (the oldest light in the universe). The earth was discovered to be bathed in a faint microwave radiation, apparently coming from the most distant observable regions of the universe. The CMB comes from all directions in space and has a uniform temperature of 2.73 Kelvin (degrees above absolute zero).
The fact that the CMB temperature is uniform presents a tremendous problem for the big bang models. There just hasn't been enough time for the exchange of radiation - light - to allow the temperature to become so uniformed. This is known as the light-travel-time problem.
Another way to look at the problem is that the visible universe is estimated at about 46 billion light years across, based on the cosmic light horizon. NASA has calculated the universe to be 13.7 billion years old, which is not enough time for light to have traveled across the universe.
In order to bridge the time requirement, NASA uses the ‘inflation' scenario (see image A). With the inflation scenario, the expansion rate of the universe was vastly accelerated in an ‘inflation phase' early in the big bang model. According to this scenario, different regions of the universe were in such close contact before the inflation phase took place that they were able to come to the same temperature by exchanging radiation before they were rapidly pushed apart.
Currently, there are several competing versions of the inflation model. Each version runs into its own set of difficulties. One difficulty they each run into is determining what physical mechanism triggered the inflation period. A corresponding difficulty is determining how to stop the inflation period once it starts - the ‘graceful exit' problem.
Considering the inflation model being used is still in debate, How can NASA "precisely" calculate the age of the universe. How many assumptions can we make and still claim our results are "precisely" accurate?
FoxNews.com Happy Birthday Universe (Give or Take a Few Dozen Millennium), February 4, 2010.
NASA Press Release: RELEASE: 03-064, NASA Releases Stunning Images of Our Infant Universe
Kraniotis, G.V., String cosmology, International Journal of Modern Physics A 15(12):1707-1756, 2000