Short answers, pulled from the story.
Luke Howard created the Latin classification system for clouds in 1802. He was a London apothecary who published a paper that established the five physical forms of clouds still used by meteorologists today. His work transformed the study of clouds from superstition into a rigorous science.
The five physical forms of clouds defined by Luke Howard are stratiform, cumuliform, stratocumuliform, cumulonimbiform, and cirriform. These forms are further subdivided into ten basic genera including cirrus, cumulus, stratus, and nimbostratus. Each genus has specific species and varieties that describe structural details and patterns.
Clouds form when air becomes saturated by cooling to its dew point or by gaining sufficient moisture from an adjacent source. The primary mechanism is adiabatic cooling where air rises and cools without exchanging heat with its surroundings. Water vapor condenses onto tiny particles known as cloud condensation nuclei such as salt or dust to create visible droplets or crystals.
Clouds on other planets and moons are made of substances like methane, ammonia, and sulfuric acid instead of water. Venus has thick clouds composed of sulfur dioxide while Jupiter and Saturn feature outer decks of ammonia and inner decks of water. Saturn's moon Titan has cirrus clouds believed to be largely methane.
Tropospheric clouds exert a dual influence on Earth's climate by acting as both a cooling and warming agent. White cloud tops reflect incoming solar radiation to promote cooling while water in clouds absorbs longwave radiation to cause warming. Measurements by NASA indicate that the cooling effects of low and mid-level clouds generally outweigh the warming effects of high layers.
Noctilucent clouds are found near the top of the mesosphere at about 80 kilometers in polar regions. They are caused by convective lift in the mesosphere during polar summer which produces adiabatic cooling of small amounts of water vapor. Smoke particles from burnt-up meteors provide much of the condensation nuclei required for their formation.