Scale of the Universe

One thing that can be difficult to grasp in astronomy is the distance scales involved.  This Flash animation helps give a sense of some of those scales.  Sorry for the ads by the way.  It appears that the original website is no longer being maintained.

The animation begins at a 1 meter scale, showing the size of familiar objects like a beach ball or an average-sized person.  If you move the slider at the bottom to the right, it increases the length scale displayed in the bottom right corner of the animation), expanding the view outwards.  You begin to see larger animals, then buildings.  Zooming out past the 1km level, you see some smaller astronomical bodies, such as Mars' moon Diemos and Halley's comet shown together with geological features on Earth.

White Dwarf Size Comparison

To see the first star in the animation, the white dwarf Sirius B, you need to zoom out to around 10^7 meters. There, you can see that it is not much larger than Earth and smaller than the gas giants in our solar system (and apparently also the Minecraft world).  You continue seeing larger stars until 10^12 meters, at which scale they are compared to the size of our entire solar system.

Continuing to zoom out, you see nebulae of increasing size.  While not photorealistic, I think the diagrams of these look particularly nice.  It continues extending out to show galaxies, clusters of galaxies, and superclusters.  The final limit is 10^27 meters with "the estimated size of the universe."

If you move the slider to the left, you can move into the world of the very small.  This includes scales from the microscopic to the subatomic.  Rather than trying to describe any other comparisons I find interesting, I'll just say it's definitely worth a few minutes to takes a look (assuming you haven't already).