Alien planets are celestial bodies that orbit stars outside our solar system, known as exoplanets. They can vary widely in size, composition, and distance from their parent stars. Some may be rocky like Earth, while others could be gas giants similar to Jupiter or Saturn. Scientists use telescopes to detect these planets and study their atmospheres and potential for supporting life. Many alien planets are located in the habitable zone, where conditions might allow liquid water to exist. This zone is crucial for the possibility of life as we know it. Ongoing research aims to discover more about these distant worlds and their characteristics.