The term extraterrestrial (or alien) typically refers to an entity or object that has originated from outside of our own planet. The word itself is a combination of the latin words extra
(meaning 'outside') and terrestris
(meaning 'of the Earth').
In popular culture, the idea that the Earth is being actively visited by beings from a technologically sophisticated extraterrestrial civilization is heavily linked to the UFO phenomenon.
The search for evidence of extraterrestrial life (including primitive organisms) on other planets such as Mars is also a major focus of the scientific community, with space agencies such as NASA devoting significant funds and resources to determining whether or not the Red Planet is (or was) inhabited.
There have been numerous cases over the years or alleged encounters with extraterrestrial entities, most commonly in association with sightings of unidentified flying objects.
Witness descriptions vary wildly, and include:
- Short, 'grey', hairless humanoid entities with large, black eyes and a thin slit for a mouth.
- Tall, 'reptilian' humanoids with skin resembling that of a lizard or other reptile.
- 'Little green men' - stereotypical small, green-skinned humanoids with large eyes.
- Beast or ape-like humanoids (prompting speculation over connection to Bigfoot sightings).
- Robotic entities of various shapes and descriptions.
- 'Nordics' - described as human-like with blonde hair and blue eyes.
Some witnesses describe entities wearing silver spacesuits or long flowing robes, while others maintain that the otherwordly visitors wore nothing at all.
The alien abduction phenomenon, which involves individuals (usually referred to as 'abductees') being taken aboard an alien spacecraft against their will, is surprisingly widespread.
Witnesses will typically describe periods of missing time, amnesia, strange bruises and flashbacks or dreams pertaining to the experience itself.
Some abductees who have undergone hypnosis have described vivid recollections of the event, sometimes recalling undergoing invasive, unidentified medical procedures.
There have even been cases of abductees communicating with their alleged alien captors.
The Search for Alien Life
For decades, astronomers have been scouring the heavens for signs that we are not alone in the universe. SETI (the Search for Extraterrestrial Intelligence) has been at the forefront of this effort, devoting huge amounts of time and resources to searching for alien signals.
In more recent years, efforts have been made to look for evidence of large, alien-built structures orbiting distant stars, while NASA has been looking for evidence of primitive life on Mars.
The James Webb Space Telescope has started to analyze the atmospheres of nearby extrasolar planets for signs of life, while efforts are also being made to look for possible signs of life in the subsurface oceans of frozen moons within our own solar system such as Europa and Enceladus.
So far, we have yet to find anything conclusive, but that could easily change in the future.