Saturn has its own set of seismometers in the form of its rings. Saturn's vibrations will travel through the rings as waves, ripples, and twists, similar to an earthquake rattling piano strings. Scientists can use these seismic signals to learn more about the structure of the planet and its interior.
In addition to being a great teacher, Saturn is a great student. Its movements are dictated by gravity along with magnetic forces. These same forces are what make up our Earth's core, which is where most earthquakes occur. Thus, Saturn provides us with a unique opportunity to witness the birth of planets and to study their destruction too.
The last time we detected a significant seismic signal from Saturn was in 2004. At that time, scientists observed a sharp increase in activity that lasted for several months before dropping back down to normal levels. They think this event may have been caused by a collision between two large moons called Titan and Enceladus. There's a chance this could have released enough energy to power a small city for one million year!
Seismic activity has since dropped again but it hasn't gone away completely. We can see signs of it every time we look at Saturn's images. The giant rings constantly change shape due to gravitational interactions between the particles that make them up and within them.
Saturn's rings are ringing like a bell, allowing astronomers to peer deep into the planet's core. Gravitational forces propel seismic waves from Saturn's core towards its ring system, where NASA's Cassini spacecraft detected the minute tremors. The sound wave reaches Saturn about 30 minutes later.
These gravitational waves are similar to those produced by a bell as it is struck by wind against a fixed surface. The amplitude of the vibration increases as it travels out through the ring system, just as you would expect if you were to hit a drum with a stick.
The wavelength of the sound wave is about 10,000 km, which means that each ring segment produces a small note when it vibrates. But the total mass of the ring system is much greater than the mass of Saturn's core, so most of the energy is dissipated as heat rather than transmitted back to Saturn's interior.
The frequency of the signal is very low, about 0.1 hertz, which means that it is difficult to hear with the human ear. However, because the ring system is massive, it can be thought of as being solid and therefore capable of transmitting sound. By measuring the time between bursts of sound, scientists have found that the ring system spins rapidly, almost as fast as Saturn itself.
The noise from Saturn's rings was first noticed by Galileo during his observations in 1610.
Rings. The rings of Saturn are assumed to be fragments of comets, asteroids, or shattered moons that broke apart before reaching the planet and were blasted apart by Saturn's tremendous gravity. They are composed of billions of microscopic ice and rock fragments covered with another substance, such as dust. The largest particle in the ring system is likely to be 2018 WD >2632, which measures about 12 miles (20 km) in diameter.
Saturn's main ring is the most obvious feature on its face. It is a thin, flat ring made up of countless particles of ice and rock that range in size from 0.5 inches to more than 50 miles (80 km).
The other two major rings are less evident but still visible. They are called E-ring and I-ring. The E-ring is made up of smaller particles than the main ring, so it appears to be an arc just outside the main body of the planet. The I-ring is much fainter but still discernible with the naked eye under good viewing conditions. It forms a rough circle around the equator of Saturn and is made up of larger rocks and minerals than the E-ring.
These three rings form a barrier between Saturn and its inner world, which would otherwise be exposed to intense heat from within.