planeet

Planeet is the Dutch term for planet. In astronomy, a planeet is a celestial body that orbits a star, has sufficient mass for self-gravity to shape it into a nearly round form, and has cleared the neighborhood around its orbit. The word is used in Dutch-language astronomy and education to describe the same class of world as in English.

The International Astronomical Union (IAU) defined three criteria for a body to be considered a planet within our Solar System: it orbits the Sun, is nearly round in shape, and has cleared its orbital neighborhood of other debris. Bodies that do not meet all criteria are classified differently, such as dwarf planets or small Solar System bodies. The term exoplanet is used for planets outside the Solar System, discovered around other stars.

In the Solar System, eight major planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They differ in size, composition, and distance from the Sun, yielding terrestrial planets in the inner part and gas or ice giants in the outer part. Pluto was formerly considered the ninth planet but was reclassified as a dwarf planet in 2006.

Exoplanets, or planets beyond the Solar System, number in the thousands and span a wide range of sizes and orbital configurations. They are detected with methods such as transit photometry and radial velocity, and many are studied to understand planetary formation and the potential for habitable environments.