Infinity.....well we look/measure as far as we can and when we can see no further we have to stop looking/measuring...that is infinity. We can only imagine or theorize what lies beyond.
We live but a century, if we are very lucky, that is like a speck of dust in the universe.....and the things we can see is still like only a tiny speck of dust in the universe.
Rather than wasting time pondering about how big infinity is we should be making the best of our lives and the lives of others.