stylistic:style_transfer, quality:correction, structural:scholar_edition, information:filtering
Description

A giant planet is a massive planet and has a thick atmosphere of hydrogen and helium. They may have a condensed "core" of heavier elements, delivered during the formation process. This core may be partially or completely dissolved and dispersed throughout the hydrogen/helium envelope. In "traditional" giant planets such as Jupiter and Saturn (the gas giants) hydrogen and helium make up most of the mass of the planet, whereas they only make up an outer envelope on Uranus and Neptune, which are instead mostly composed of water, ammonia, and methane and therefore increasingly referred to as " ice giants ".

Extrasolar giant planets that orbit very close to their stars are the exoplanets that are easiest to detect. These are called hot Jupiters and hot Neptunes because they have very high surface temperatures. Hot Jupiters were, until the advent of space-borne telescopes, the most common form of exoplanet known, due to the relative ease of detecting them with ground-based instruments.

Giant planets are commonly said to lack solid surfaces, but it is more accurate to say that they lack surfaces altogether since the gases that form them simply become thinner and thinner with increasing distance from the planets' centers, eventually becoming indistinguishable from the interplanetary medium. Therefore, landing on a giant planet may or may not be possible, depending on the size and composition of its core.