NASA’s Cassini probe, which reached Saturn in 2004, found the rings of this planet bright and clean. Scientists have decided that if the rings had appeared by the time Saturn was formed 4.5 billion years ago, they would not look so bright today. Modeling based on information from Cassini gave the rings an age of 100 to 400 million years, making them the same age as dinosaurs. However, Japanese scientists disagreed with this and presented their analysis, aging the rings to the age of Saturn.
Image source: NASA
As the author of the new work, Professor Ryuki Hyodo of the University of Tokyo, admits, as a planetary scientist, it is strange for him to hear that in the Solar System, which was mainly formed 4.5 billion years ago, there could be something new on such a scale as rings at Saturn.
Previous analyzes of Cassini data focused on how and at what speed micrometeoroids bombard Saturn’s icy rings. These objects, which are about the size of a grain of sand, pollute the rings and evaporate ice from them, making them dimmer. In 4.5 billion years they would have been able to completely eliminate our ability to observe the rings, but since this did not happen, Saturn’s rings appear to have appeared relatively recently.
Professor Hiodo showed in his work that his colleagues could have misinterpreted the processes in the rings caused by the impact of micrometeoroids. According to his model, Saturn’s rings formed along with the planet about 4.5 billion years ago from icy debris that did not become part of Saturn or its moons.
«The solar system [at that time] was much more chaotic,” Hyodo explained. “Many large planetary bodies were still migrating and interacting, greatly increasing the chances of a significant event that could lead to the formation of Saturn’s rings.”
In the model of the Japanese scientist, micrometeoroids collide with rings at speeds of up to 108 thousand km/h. These collisions can create local heating up to 9725℃, causing micrometeoroids to evaporate. This gas then expands, cools and condenses in Saturn’s magnetic field, producing electrically charged ions and microscopic particles. Intense processes forced ions to leave the rings without contaminating them. Thus, the pristine purity of the rings was preserved for billions of years.
«A clean appearance does not necessarily mean that the rings are young,” the scientist says. The new work doesn’t refute the Cassini data, but it does show that previous interpretations may be wrong. The scientist denied the rings of Saturn the title of peers with dinosaurs. They are truly ancient.