The "If the Moon were only 1 Pixel" website offers viewers a look at the scale of our solar system. Visitors are show the moon represented as one pixel on the screen. Then as you scroll across the site, the rest of the solar system comes into view, eventually, since this is supposed to be to scale.
Take a few minutes to look at this website. What a cool site to let students explore on that 77 inch SMARTBoard!
If you cannot wait for all of the scrolling, look for the planet jump button at the top of the screen.