if the universe is 156 billion light years wide, and it started in the middle and worked outwards at the speed of light, wouldn't it only be 28 billion light years wide if indeed the universe is 14 billion years old?
Don't shoot the messenger, that's what it say here, so it must be true
hhttp://en.wikipedia.org/wiki/Age_of_the_universe
http://map.gsfc.nasa.gov/m_uni/uni_101age.html
Also (ripped from another forum, I am not that smart), there is a common misconception that the age of the universe (13.7 billion years) is equal to the radius of the observable universe in light years but it is actually a little more complicated than that, because spacetime is highly curved at cosmological scales (http://www.astro.ucla.edu/~wright/Dltt_is_Dumb.html).
So we only say the most distant objects we can view are up to 13.7 billion years old, but we don't say they are up to 13.7 billion light years away. Working out how far away they actually are is also a little more complicated as it involves their comoving distance. This is the difference between how far away they were from this point in space when the light was emitted from them and how far away they are theorised to be now, due to the metric expansion of space.
The metric expansion of space is a process where the metric that defines distance changes over time, meaning that in a given time any unit of measurement will change by the same factor as any other unit of measurement. So 1 meter becomes 2 meters, 1 billion light years becomes 2 billion light years, the universe doubles in size - all in the same amount of time.
As an example, the cosmic background radiation that we measure now was actually emitted around 13.7 billion years ago. The matter that the radiation was emitted from (which has since formed into galaxies) was only around 40 million light years away from the matter that formed into our own galaxy when the radiation was emitted. But those galaxies that formed are now theorised to be around 46 billion light years away from us, due to the nature of expanding space.
So using the comoving distance, the current radius of the observable universe is around 46 billion light years, giving an overall diameter of around 92 billion light years across.
But this is only the observable universe, and we do not know how much more there is than it is possible for us to observe. But we do know that the WMAP data puts a lower bound on the size of the whole universe as 78 billion light years and our observable universe is theorised to be larger than that.
some intesting discussions here:
http://www.bautforum.com/questions-answers/57581-how-wide-universe.html
Hope that helps, some.
Please let me demonstrate the ride around; really it's no trouble.