Moon and Saturn 
Seismologists use earthquakes to study the structure of the planet beneath our feet. And now, astronomers may use something similar to probe the interior of the planet Saturn.
Saturn is a very different world from Earth. It’s almost a hundred times heavier than our planet, and it consists of a dense, rocky core that’s surrounded by layers of hydrogen and helium.
Saturn is best known for its bright, beautiful rings. Recently, planetary scientists detected structures in those rings that are created by vibrations within the planet. That allows the rings to act as a seismograph that probes Saturn’s interior.
The scientists studied the innermost of Saturn’s bright rings, the C ring. Because it’s closest to the planet, it’s most susceptible to slight changes in Saturn’s gravitational field. Scientists looked at the ring with the Cassini spacecraft, which is orbiting Saturn. By looking at stars that passed behind the C ring, the scientists measured exactly how much light different parts of the ring absorb.
With this technique, the researchers mapped six waves in the ring. The waves matched predictions for how the rings should respond as Saturn’s interior sloshes around and disturbs its gravitational field. Scientists will look for additional waves to help them understand the structure of this giant world.
Look for Saturn before dawn tomorrow. It looks like a bright golden star close to the lower left of the crescent Moon.
Script by Ken Croswell, Copyright 2013