Alien life refers to any form of life that may exist outside of Earth. This can include microorganisms, plants, or even intelligent beings that could inhabit other planets or moons within our solar system or beyond. Scientists search for signs of alien life by studying extreme environments on Earth and exploring celestial bodies like Mars and the icy moons of Jupiter and Saturn. The search for alien life also involves the study of exoplanets, which are planets outside our solar system. Astronomers use telescopes to detect these planets and analyze their atmospheres for potential signs of life, such as water vapor or specific gases. The discovery of alien life would have profound implications for our understanding of biology and the universe.