Trans-Neptunian objects (TNOs) are celestial bodies located in the solar system beyond the orbit of Neptune. They include a variety of objects, such as dwarf planets, comets, and smaller icy bodies. TNOs are primarily found in the Kuiper Belt, a region filled with many small, icy worlds. These objects are important for understanding the formation and evolution of the solar system. Some well-known TNOs include Pluto, Eris, and Haumea. Studying TNOs helps scientists learn more about the conditions in the early solar system and the processes that shaped it.