With it, you can scroll down to see a representation of the microscopic (i.e. E. coli bacteria), and scroll back out to see the galactic.
ABCNews.com writes the ninth graders from Moraga, California were inspired by a teacher to create the page:
"My seventh grade science teacher showed us a size comparison video on cells, and I thought it was fascinating. I decided to make my own interactive version that included a much larger range of sizes," said Cary in an email forwarded by his mother. "It was not a school project -- just for fun. However, my science teacher loved it so much she showed [it] to the class! My brother, Michael, helped me put it on the internet."
Cary said he worked on the project, on and off, for a year and a half, getting information from Wikipedia and astronomy books. It is now spreading virally online.
H/T to the A2Chronicle