A habitable world is a planet or celestial body that is capable of supporting life, either through the presence of liquid water and a suitable atmosphere or through alternative means such as extremophiles.
Scientists look for several key factors when determining the habitability of a planet, including its distance from its star, the composition of its atmosphere, and the presence of water. They also consider the planet's size and whether it has a stable orbit.
While the majority of known habitable worlds orbit stars similar to our Sun, there is also evidence of habitable planets orbiting smaller stars such as red dwarfs. These types of stars are more common in the universe, increasing the chances of finding habitable worlds.
While liquid water is considered a key ingredient for life as we know it, there is evidence that certain extremophiles can survive in extreme environments without liquid water. These discoveries expand the potential for habitable worlds beyond those with liquid water.
Scientists use a variety of technologies to search for habitable worlds orbiting other stars, including space-based telescopes such as Kepler and ground-based telescopes with advanced imaging and spectroscopy capabilities. They also use techniques such as transit photometry and radial velocity measurements to detect potential habitable worlds.