I think the best way to do this, is to put your audience in the astronauts place.

* For instance, you can quote Jim Lovell (Apollo 8 and 13):

"When I was orbiting the moon and could put my thumb up to the window and completely cover the Earth, I felt a real sense of my own insignificance. Everything I'd ever known could be hidden behind my thumb.

Being in space also shows you how relative everything is. In this room, our whole universe is limited to these walls, the ceiling, and the floor. That's all we can see. You get in an airplane, and you start thinking in terms of cities. You think: "I've left Chicago, I'm over St. Louis now, and soon I'll be down to Houston." You get in an Earth-orbiting spacecraft, and your horizon broadens to include whole continents. On the way to the moon, you think in terms of the entire solar system. The moon is up ahead, the sun to your left, the Earth behind you."

Ask your audience to imagine being so far away from Earth that they can cover Earth with their thumb.

URL: http://www2.worldbook.com/features/f...htm&direct=yes