Extraterrestrial intelligence, often called "alien life," is intelligent life whose origins are somewhere outside of the earth. While there are many theories proposing the possibility of intelligent life, or any life, on other planets in the universe, these remain hypothetical. At the present, no widely accepted evidence has been found to convince the scientific community of the conclusive existence of extraterrestrial intelligence.

While scientists are currently conducting direct searches for bacterial or other microbial life on planetary bodies within our solar system, an indirect search, via the SETI program, is underway for intelligent life in more distant areas of the universe. Proponents of the search for extraterrestrial intelligence commonly cite the Drake Equation, developed by astrophysicist Frank Drake, which posits that there are approximately 10,000 planets in the galaxy with civilizations capable of communicating with earth.