For a spacecraft to land on the rings, they would have to present a good solid surface, just as much of Earth, the moon, and Mars do. If you look at a picture of Saturn, you might think the ring is a big disk, so you could land anywhere on it. And there definitely would be plenty of room for landing. The rings are so enormous that they are almost as wide as the distance between Earth and the moon! This would make a pretty good landing pad.

But scientists have figured out that the ring is not a solid disk. Astronomers have observed the rings with telescopes for nearly 400 years, and they have used advanced mathematics for centuries to try to understand them. Three spacecraft have paid brief visits to the distant planet and returned photos and other scientific measurements.

Even with all this information, there is still a tremendous amount left to learn. But we do know that the rings are made up of millions and millions and millions of pieces of ice and rock, ranging in size from particles so small you would not be able to see an individual one to chunks as large as a house. It is amazing that these rings can be hundreds of thousands of miles across and yet only a few hundred feet thick. You might expect that all the pieces would eventually move away from each other and the rings would break up. But the gravity of many of Saturn's moons helps keep all of those pieces in place as they orbit Saturn.

When all this material is together and we view it from far away, it appears to be solid, but if you were close enough to land on it, it would be a jumbled mess! Now you could be really daring and have the spacecraft try to land on a single large chunk within the rings, but with all the other pieces flying around, it would be a pretty dangerous place. I think that it's probably better not to try to land there but to continue to study them from a safe distance.

In just over 2 years a spacecraft named Cassini will arrive at Saturn, and it will study the rings in more detail than we can from Earth -- but still from a safe distance. The last time a spacecraft visited Saturn was in 1981, perhaps long before you were born. From 2004 through 2008, Cassini will collect information on the rings, the planet, the moons, and more. It's going to be really exciting to see what new secrets this spacecraft will uncover at Saturn.

In the meantime, you can study Saturn yourself, right here on Earth. The planet is visible in the west this month after sunset. Visit your local planetarium or science museum or ask for help at your library to find out where to look so you can pick Saturn out from the other planets and stars visible in April. You will need a telescope to see the rings, but even without one, the stars and planets hold many beautiful sights. Even if it's cloudy, you can see Saturn right inside your home and learn more about it. Go [here] to The Space Place Web site at spaceplace.nasa.gov, and choose "Spacey Things to Do" to find out how to make a model of the planet and rings.

Thanks again for calling Dr. Marc at The Space Place.