Astrobiology is the interdisciplinary science studying life's origin, evolution, distribution, and future in the universe, asking how life began, if it exists elsewhere, and what its future holds. It blends astronomy, biology, chemistry, geology, and planetary science to investigate habitable environments beyond Earth, search for biosignatures (signs of life), and understand life's resilience in extreme conditions, using Earth's extremophiles as models. Key areas include exploring Mars, icy moons like Europa & Titan, and characterizing exoplanets for potential life.