This may come as a surprise to you, but big things are big.  Take the Moon for instance.  Pretty big.  Except if you compare it to the Earth.  And the Earth is pretty big except if you compare it to the Sun.  When you scale up by orders of magnitude it becomes very difficult for the human brain to comprehend what exactly is being talked about.

That’s how politicians can throw around numbers like one trillion and scare people.  Numbers that large are so far out of our everyday experience that we can’t wrap our head around them.  I liken it to how the trip to Grandma’s house seemed like it took forever when you were a child but now it seems like a short jaunt in the car.  You have to work regularly with large numbers for them to make sense.  If you don’t work with large numbers, you should be very cautious of what conclusions you draw from anyone throwing large numbers at you.  It is likely that they’re taking the large numbers out of context to make them scarier than they actually are.

All that to say that when you try to wrap your head around things that are big, it’s good to have a familiar frame of reference to compare to.  That’s what makes this picture of the continental United States superimposed on the Moon so useful.  The U.S. is about 3,400 kilometers across at its widest longitude and the Moon has a circumference of around 11,000 kilometers.  So this looks about right if it isn’t perfect.

Kind of cool, huh?