Trans-Neptunian objects (TNOs) are celestial bodies that exist beyond Neptune in the outer regions of the solar system. These objects are typically composed of rock, water ice, and other frozen substances, and are believed to be remnants from the early formation of the solar system. TNOs are divided into several categories, including Kuiper Belt objects, scattered disc objects, and detached objects. They vary in size from small, icy bodies to larger dwarf planets like Pluto and Eris. Some TNOs have highly elongated orbits that take them far away from the Sun, while others have orbits that are more circular and closer to Neptune. Studying TNOs can provide valuable insights into the early history of the solar system, as well as the processes that govern the formation and evolution of planetary systems. Researchers use a variety of telescopes and spacecraft to observe and study TNOs, with the goal of understanding their compositions, origins, and orbital dynamics.