Final answer:
Cirrus clouds are high-altitude clouds composed of ice crystals, often indicating forthcoming weather changes and contributing to the Earth's climate system. They are thin and wispy and have counterparts on other planets, such as Neptune, where they consist of methane ice crystals.
Step-by-step explanation:
Cirrus clouds are high-altitude clouds that typically form above 20,000 feet (6,000 meters). These clouds are composed of ice crystals and appear thin, wispy, or feathery. The presence of cirrus clouds often indicates that a change in the weather may be on the horizon, as they can signal an approaching front. Distinctive for their thin, ribbon-like appearance, these clouds do not typically result in precipitation that reaches the ground, as the ice crystals evaporate before descending to lower, warmer altitudes. However, they do contribute to the Earth's climate by reflecting incoming solar radiation and trapping outgoing heat, playing a role in the greenhouse effect. Observations of cirrus clouds on planets such as Neptune also provide insight into the atmospheric conditions beyond Earth, with some extraterrestrial cirrus clouds being composed of methane ice crystals.