And on that note, the creator has made the common mistake of performing the calculation speed_of_light * age_of_universe to determine the radius of the observable universe.

Space has expanded during the lifetime of the universe so the objects that emitted light at the edge of the observable universe have moved further away since emitting the light. The estimated distance to the edge of the observable universe is more like 47 billion light-years: http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN

The visible universe, however, is a bit smaller since we can only see as far as the surface of last scattering: http://en.wikipedia.org/wiki/Cosmic_microwave_background_rad...