Just a bit of Life, the Universe, and Everything before bedtime

Last night, just after Brushing and Flossing, and before starting Snuggly Reading Time before Lights Out.
E: Mom, what is at the end of space?
M: Well, some people think at the end of the universe there's the edge of another universe.  And at the edge of that, another.  Like a bunch of bubbles.
E: Ohhhhh.... that's great! Because then the aliens are in the different universe.
M:  Maybe.  But some people think that at the end of our universe, there's nothing.
E: (with fearful look)  But then, noooooo.  Then that means the aliens are in OUR space.