: In a legal context, an alien is a person in a country who is not a citizen of that country.
Outside of space, "alien" has a specific legal meaning regarding human movement and national borders. : In a legal context, an alien is
: In the United States, once an alien gains admission and develops ties, their constitutional status changes, according them a "generous and ascending scale of rights". : NASA uses a multi-level scale to verify alien life
: NASA uses a multi-level scale to verify alien life. Reaching "level seven" would mean ruling out all non-biological explanations and having secondary evidence, like a radio signal. : In a legal context
: Scientists suggest looking at non-human intelligence on Earth—like octopuses, crows, or bees—as a way to prepare for how truly different alien minds might be. 2. Legal and Societal Definitions
ArtI.S8.C18.8.7.2 Aliens in the United States - Constitution Annotated
In science, an "alien" is any organism that did not originate on Earth.