One of the things I like to do when I travel is to find unique things in the places I visit. And when I visited the city of Zagreb, Croatia, I learned about a sculpture that had quite an interesting story.

In 1971, the artist Davor Preis installed a sculpture of a bronze sphere in the center of Zagreb and called it the Grounded Sun. It sat on its on in the city until 2004, when an artist created small models of the planet and installed them around the city, creating a scale model of the solar system. But the artist never made a big announcement about the planets, and so even people who noticed one of the planets didn't realize that the entire solar system was represented! Eventually, a group of physics students were able to find and map all the planets, which was a challenge because Pluto was over four miles away from the Grounded Sun.

Of course, with Google Maps, the planets are now relatively easy to find. I went as far as Saturn before I gave up (as it would have taken hours of walking to get to the rest). But it was a really neat marriage of art and science, and it got me to visit parts of the city that I would have never gone to.

Sample Problems

1. Given that the radius of the Grounded Sun was 1 meter, find the ratio of the radius of the actual sun (which you can look up online) to the radius of the Grounded Sun.

2. Use this ratio, along with the radii of the planets in our solar system (which you can look up online), to find the sizes of the other planets that Preis created.

3. Use this ratio, along with the average radii of each planet's orbit (which you can look up online), to find the distances between each planet and the Grounded Sun that Preis had to use.

4. Determine what a similar project would look like in San Francisco. Pick a location for a new version of the Grounded Sun (you can choose Ram Plaza, Civic Center, or your favorite San Francisco location), and find interesting places where you could put the planets so that they were the correct distances away from the Grounded Sun.