How many universe are there?

How many universe are there?

If we define “”universe”” as “”all there is”” or “”all that exists,”” then obviously, by definition, there can be only one universe. But if we define “”universe”” as “”all we can ever see”” (no matter how large our telescopes) or “”space-time regions that expand together,”” then many universes may indeed exist. Dec 23, 2015