The astronomical unit (Earth-Sun distance, about 150 million kilometers) is a yardstick that conveys some idea of cosmic distances reaching far beyond the dimension of the solar system. Light from the most distant detected galaxies has traveled about 13 billon years, covering the unimaginable distance of thousand trillion astronomic units [1] .
More on astronomical distances and telescopes
Nobody knows how large the universe is, or whether it has any boundary at all. In one of many possible views, the diameter of a spherical 'observable' universe could be envisaged to measure 93 billion lightyears based on the notion of 'comoving'.