Although reflection from the rings increases Saturn’s brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn’s rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. Although many people think of Saturn’s rings as being made up of a series of tiny ringlets (a concept that goes back to Laplace), true gaps are few. It is more correct to think of the rings as an annular disk with concentric local maxima and minima in density and brightness. On the scale of the clumps within the rings there is much empty space.
Beneath The Icy Crust Of Enceladus. The research paper written by scientists with the Cassini mission, published in the journal Science, suggests the presence of hydrogen gas. Hydrogen gas, that could potentially provide a chemical energy source for life, is pouring into the subsurface ocean of Enceladus from hydrothermal activity on the seafloor of this bewitching, distant moon-world.
Therefore, the results of the new study support the idea that primitive life could potentially have evolved on Ganymede. This is because places where water and rock interact are important for the development of life. For example, some theories suggest that life arose on our planet within hot, bubbling seafloor vents. Before the new study, Ganymede's rocky seafloor was believed to be coated with ice--not liquid. This would have presented a problem for the evolution of living tidbits. The "Dagwood sandwich" findings, however, indicate something else entirely--the first layer on top of Ganymede's rocky core might be made up of precious, life-sustaining salty water.
The team discovered that the Methone's density would be about 300 kilograms per cubic centimeter. That amounts to less than a third of the density of water, making Methone less dense than any other known moon or asteroid in our Solar System!