Extraterrestrial life (from the Latin words: extra and terrestris ) is defined as life that does not originate from Earth. It is often also referred to as alien life, or simply aliens (or space aliens, to differentiate from other definitions of alien or aliens). These hypothetical forms of life range from simple bacteria-like organisms to beings far more complex than humans.
The development and testing of hypotheses on extraterrestrial life is known as exobiology or astrobiology; the term astrobiology, however, includes the study of life on Earth viewed in its astronomical context. Many scientists consider extraterrestrial life to be plausible, but there is no conclusive evidence for its existence. Since the mid-20th century, there has been an ongoing search for signs of extraterrestrial life, from radios used to detect possible extraterrestrial signals, to telescopes used to search for potentially habitable extrasolar planets. It has also played a major role in works of science fiction.
Read more about Extraterrestrial Life: Background, Possible Basis, Planetary Habitability in The Solar System, Scientific Search, The Drake Equation
Famous quotes containing the word life:
“What if there are not only two nostrils, two eyes, two lobes, and so forth, but two psyches as well, and they are separately equipped? They go through life like Siamese twins inside one person.... They can be just a little different, like identical twins, or they can be vastly different, like good and evil.”
—Norman Mailer (b. 1923)