I used to think Planet Earth was a pretty big place. That was
before I gained a little perspective. A few months ago, my
husband and I were driving to a friend’s house. While looking up
at a streaky afternoon sky, I was jabbering on about how far
away the moon was, since it was already visible. (I had only
recently started reading up on the subject, and the whole thing
was freaking me out, quite frankly.) When I mentioned how big
our galaxy is, my husband paused for a moment, then proclaimed,
“We are Who-ville!” And that’s a very good way to wrap your mind
around it. Remember the book Horton Hears a Who by Dr. Seuss?
Our Earth (which seems so very, very huge to us), is equivalent
to a speck on a clover being carried around by an elephant on
top of something else that is the size of our Earth. Except,
actually, we’re much, much smaller than that. Size is relative,
of course. To a human standing at the edge of the Grand Canyon,
the Grand Canyon is enormous. Ditto for someone at the foot of
Mt. Everest, or someo