The Cassini spacecraft from NASA has revealed that rings around the planet Saturn are as old as our solar system.
The rings and moons around Saturn were revealed to be over four billion years old, dating back to the time when planetary bodies in the solar system first formed from the protoplanetary nebula, the material cloud that orbited the Sun after it was created. The new discovery marks an important find for the understanding of our solar system.
"Studying the Saturnian sytem helps us understand the chemical and physical evolution of our entire solar system," says Gianrico Filacchione, the study's lead author from Italy's National Institute for Astrophysics. "We know now that understanding this evolution requires not just studying a single moon or ring, but piecing together the relationships intertwining these bodies."
The researchers made their discovery using data from Cassini's visual and infrared mapping spectrometer (VIMS). The data showed the way in which water ice and colors, which indicate non-water and organic materials, are located in the Saturnian system. They found that the planet's moons and rings displayed a reddish hue, with the moons redder in color the further they were from Saturn.
The red color likely derived from oxidized iron and was possibly caused by a showering of meteoroids. The coloring is only on the surface, meaning that the deeper core is likely much older. They also deduced that the moon Prometheus, much redder than the others, may have been formed from material in Saturn's rings.
A large amount of water ice was also found, too big an amount to have been left by comets or other more recent objects. It is more likely that the ice formed during the origin of the solar system, given that Saturn is located beyond the "snow line," the distance from the Sun that marks how easily ice is preserved. The Sun dissipates ice more easily within the snow line.
The discovery has implications not only for our solar system, but for other systems as well.
"Observing the rings and moons with Cassini gives us an amazing bird's-eye view of the intricate processes at work in the Saturn system, and perhaps in the evolution of planetary systems as well," said researcher Linda Spilker in a press release. "What an object looks like and how it evolves depends a lot on location, location, location."
Findings of the study are published in The Astrophysical Journal.
