Answer:
The value of a theory associated with a definition is illustrated by examples of life that are conceivable but are excluded by the definition, where the exclusion is justified by a constructive belief that such life-forms are not possible. Many of these can be extracted from popular culture.For example, the crew of Star Trek (The Next Generation) has encountered conceptual aliens that do not fit the NASA definition. The nanites that infected the computer of the next-generation Enterprise in Episode 50 (“Evolution”) are informational (or perhaps electromechanical, but in any case not chemical); their evolution is not tied to an informational molecule like DNA (although they require a chemical matrix to survive). The Crystalline Entity of Episode 18 (“Home Soil”) appears to be chemical but not obviously Darwinian; it seems to have no children. The Calamarain (Episode 51: “Déjà Q”) are made of pure energy, not chemicals. And the sentient being known as Q (Episode 1: “Encounter at Farpoint,” and others) appears to be neither matter nor energy, flitting instead in and out of the Continuum without the apparent need of either.Off screen, other fictional forms of life appear to defy the NASA definition. For example, Fred Hoyle published a story The Black Cloud, a fictional entity that floats into our Solar System and blocks our sunlight, placing Earth in distress. After the black cloud realizes that the Earth holds self-aware forms of life, it politely moves out of the way and apologizes.