Why some planets have rings?
Probably one of the most fascinating aspects of our solar system is the phenomenon (現象) of planetary rings (行星環). Saturn (土星) is by far the most impressive planet with its beautiful collection of thousands of tiny, coloured rings, even though many planets also have rings. However, why do some planets have rings? According to scientists, the major moons (衞星) and the rings of gas giants (氣態巨行星) like Saturn, Jupiter (木星), Uranus (天王星) and Neptune (海王星) formed at the same time. Any material that is too close to one of these planets cannot stick to a moon. Instead, it disperses(分散) into an orbit around the object because of the planet’s strong gravitational pull (重力牽引). This same process is thought to be responsible for the formation of the rings of smaller planets such as Mercury (水星), Venus (金星) and Mars (火星). Different planets have very different rings in terms of composition (成份). Jupiter’s rings are primarily made up of dust and …Read More