// How Big Is the Universe?

Powers of Ten

Let’s take a little trip from Earth to the outer reaches of our Universe. We are going to looking back at the Earth all the time so we’ll be traveling backwards. Don’t worry—I’ll make sure we don’t run into anything!

DIGITAL EFFECT: Powers of 10 Style
If possible on your system, run a “Powers of 10” style tour. For example, start 107m away from Earth, and move away in increments of powers of 10 (108 to 109etc.). In the interface, create comments throughout the tour with helpful information about the current distance. Let the names of each function give an idea of how the view will move, and what is visible at that distance—e.g., “108 MOON” would move the view to 108 m from Earth, where the Moon & its orbit are visible.
Go out as far as you like. Presenters are in no way obligated to run the entire tour—one may stop at any distance, and then move on to the next activity.
See Appendix: Powers of 10 Style Universe Tour for full details on the tour.
DIGITAL EFFECT: Orbit Earth
Slowly orbit Earth, 15 x 106 m away, at a sweetspot location of 180° azimuth and 45° elevation—adjust if a different sweetspot location is desired. Use as a “quick return” home to in anticipation of discussing using radar closer to home. Also set the time to 2012/10/02 at early evening in your local latitude and longitude, to match the iniital date at startup. 
VISUAL (alternative movie): Powers of Ten
If the digital tour is not possible on  your system, show Powers of 10 video. Narrate it yourself with background audio of space music or use the video narration. The video can are found at NASA’s Astronomy Picture of the Day – http://apod.nasa.gov/apod/ap110201.html

This “Powers of Ten” section may be moved to end of the program if desired.

In this tour, we have seen what the distances may be to various parts of our Universe. But do you believe those distances? How did people measure the distances to things so far away? In this program, you will find out how we know how far away things are. 

Let’s start with some nearby things and find out how we can figure out how far away they are.