China News Service, Beijing, February 8 (Reporter Sun Zifa) A newly published astronomy paper in the internationally renowned academic journal "Nature" believes that there may be hidden objects hidden under the surface of the pitted icy shell of Saturn's moon Mimas (Mimas). ocean.
Analyzing data from observations of Mimas by the Cassini spacecraft shows that this ocean is relatively new and continues to evolve. Further studies of Mimas may provide a better understanding of how this icy world formed.
Schematic diagram of the results of this research (picture from Fre?de?ric Durillon, Animea Studio Paris Observatory). Photo courtesy Springer Nature
According to the paper, there is growing evidence that some satellites may have oceans beneath their surfaces, but detecting these water worlds is difficult. Mimas, a small moon of Saturn, is an unlikely candidate because its surface properties are different from other icy moons such as Enceladus. The first author and corresponding author of the paper, V. Lainey of the Paris Observatory in France, and colleagues and their collaborators evaluated Cassini's observations of this small satellite, which challenged previous theories.
Previous studies have proposed two possibilities for Mimas' interior: an elongated rocky core and a global ocean. In this study, the latest analysis by the authors of the paper revealed the changes inside the small satellite that affect its rotation and orbit. When applying the solid model, the rock core needs to be elongated, which is inconsistent with observations. But measurements of Mimas' position suggest its orbit is better explained by the influence of its internal ocean. Their calculations show that the ocean lies about 20-30 kilometers deep beneath the ice shell, and simulations suggest that it emerged 25 million to 2 million years ago, so signs of this underground ocean have not had time to leave traces on the surface.
Schematic diagram of the results of this research (picture from Fre?de?ric Durillon, Animea Studio Paris Observatory). Photo courtesy Springer Nature
The authors of the paper concluded that the results of this study indicate that recent processes on Mimas may be common in the early formation stages of other icy planets.
"Nature" published a "News and Views Article" by peer experts at the same time, saying that the new findings of this study will promote a comprehensive survey of medium-sized icy satellites in the entire solar system. (over)