[eishtmo]

The 46.5 billion light-year distance is TODAY's distance to the observable Universe's limit.

The Universe has been expanding in size since it first appeared 13.8 billion years ago. Since the Universe was smaller in the past, light could travel a further distance in the same time interval. For example, when the Universe was half its current size, a photon traveled 2 light-years every year. Light's "total travel distance" is deduced from its observable redshift z .

If the Universe stopped expanding today, it would take 45.6 billion years for Earth's expanding electromagnetic bubble to reach the edge of today's observable Universe, more than triple the Universe's current age.

The a(t)=3.4 (=46.5/13.8) scale multiplier, which accounts for the Universe's expansion, scales as ~ t^{⅔} where t is a time interval parameter since the Big Bang. See Ned Wright's comprehensive cosmology site for more details. <https://www.astro.ucla.edu/~wright/cosmology_faq.html#z>