Artificial planet
Proposed stellar megastructure / From Wikipedia, the free encyclopedia
Not to be confused with Soviet spacecraft Luna 1, the first human-made object to reach heliocentric orbit and dubbed "Artificial Planet 1".
An artificial planet[1] (also known as a planetary replica or a replica planet)[2] is a proposed stellar megastructure. Its defining characteristic is that it has sufficient mass to generate its own gravity field that is strong enough to prevent atmosphere from escaping,[3][4] although the term has been sometimes used to describe other types of megastructures that have self-sufficient ecosystems.[2][5] The concept can be found in many works of science-fiction.