island universe

By the end of the decade, Hubble had not only shown that the spiral nebulae were “island universes,” he also had begun to classify different galaxy types and think about how they evolved over time.

The universe as Edwin Hubble had imagined it, chock-full of island universes, was captured in one hard look.

They were now so near the Island Universe that the stars spread out in a huge disc ahead of them.

An exploring-ship was on its way to a second island universe.