Curious Kids is a series for children in which we ask experts to answer questions from kids. For a very long time, Saturn was thought to be the only planet in our solar system with rings. The rings around Saturn were discovered by an astronomer called Galileo Galilei nearly years ago.
He used a very simple telescope that he constructed himself from lenses and pointed it at the planets in the night sky. One of the first objects he looked at was Saturn. Since then, astronomers — who study the universe and everything in it, like planets — have used bigger and better telescopes to find rings around all of the outer gas giant planets: Jupiter, Saturn, Neptune and Uranus.
These planets, unlike others in our system, consist largely of gas. The first theory states that the rings formed at the same time as the planet. Some particles of gas and dust that the planets are made of were too far away from the core of the planet and could not be squashed together by gravity. They remained behind to form the ring system. The second theory , and my personal favourite, is that the rings were formed when two of the moons of the planet, which had formed at the same time as the planet, somehow got disturbed in their orbits and eventually crashed into each other an orbit is the circular path that the moon travels on around the planet.
They are the four giant gas planets Jupiter, Saturn, Uranus, and Neptune. Saturn, which has by far the largest ring system, was known to have rings for a long time. It was not until the s that rings were discovered around the other gas planets. The rings around Jupiter, Uranus, and Neptune are much smaller, darker, and fainter than the rings of Saturn. Rings around gas giants are thought to be transient over the the lifetime of the planetary system.
That is, if we had lived at a very different time, perhaps we would not see big rings around Saturn, but another one of the gas giants.
Javascript must be enabled to use Cool Cosmos. The rings of Saturn , meanwhile, have been known for centuries. Although Galileo Galilei became the first person to observe the rings of Saturn in , he did not have a powerful enough telescope to discern their true nature. It was not until that Christiaan Huygens, the Dutch mathematician and scientist, became the first person to describe them as a disk surrounding the planet.
Subsequent observations, which included spectroscopic studies by the late 19th century, confirmed that they are composed of smaller rings, each one made up of tiny particles orbiting Saturn. These particles range in size from micrometers to meters that form clumps orbiting the planet, and which are composed almost entirely of water ice contaminated with dust and chemicals.
In total, Saturn has a system of 12 rings with 2 divisions. It has the most extensive ring system of any planet in our solar system. The rings have numerous gaps where particle density drops sharply. Well beyond the main rings is the Phoebe ring, which is tilted at an angle of 27 degrees to the other rings and, like Phoebe, orbits in retrograde fashion. The rings of Uranus are thought to be relatively young, at not more than million years old.
They are believed to have originated from the collisional fragmentation of a number of moons that once existed around the planet. After colliding, the moons probably broke up into numerous particles, which survived as narrow and optically dense rings only in strictly confined zones of maximum stability. Uranus has 13 rings that have been observed so far. They are all very faint, the majority being opaque and only a few kilometers wide.
The ring system consists mostly of large bodies 0. A few rings are optically thin and are made of small dust particles which makes them difficult to observe using Earth-based telescopes.
The rings of Neptune were not discovered until until the Voyager 2 space probe conducted a flyby of the planet.
0コメント