Phoebe, Saturn’s biggest ring has broken its own record. Despite being invisible to the naked eye, scientists discovered that it is two times as thick as what was once previously presumed.
The journal Nature, which published the study, finds that this monstrous ring is comprised mostly of tiny particles, which could shed fresh insight on the Saturnian ring system evolution.
A University of Maryland, College Park planetary scientist, Douglas Hamilton, the study lead author said, “I was giving talks, saying Saturn has a giant invisible ring, which makes you sound just perfectly crazy. It is 10 to 20 times larger than the second-biggest ring, so this thing is absolutely gargantuan.”
Most of Saturn’s rings appear to hug the planet, that forms the beautiful striped disc, the gas giant is known for. In 2009, NASA’s Spitzer Space Telescope detected another ring so massive, the entire planet and its main rings seems to appear like a small dot in the middle.
Though, difficult to detect in visible light, the ring can be clearly viewed like a spectral halo at infrared wavelengths.
Hamilton and his colleagues at first went to look for this “giant invisible ring” due to the strange two-tone color of Iapetus, one of Saturn’s moons. One side appears pale, while the other side is dark, making it appear as if covered in soot. Hamilton and his team hypothesized that the unseen particles from farther out were hitting Iapetus and blackening one side, since Iapetus is tidally locked to Saturn and is not capable of rotating fast enough to get an all-around coating.
“If that material was coming inward and coating the face of Iapetus, then maybe we could see the ring. Usually those things don’t pay off, but this one did, ” Hamilton said.
The ring stretched from 4.8 M to 7.76 M miles, estimated the scientists, and though Spitzer has a relatively narrow field of view, they couldn’t really ascertain as to its exact thickness.
The key to understanding the reason why the particle size distribution is so skewed might offer researchers “a window into the history of the Saturn system,” said Hamilton.