What concept represents the most radical departure from traditional astrobiology regarding life's necessary environment?

Answer

The suggestion that primitive life might not require a planetary body at all, existing directly in interstellar space.

The idea that life could originate or reside diffusely in interstellar space, independent of any planet, represents the furthest departure from conventional planetary habitability searches.

What concept represents the most radical departure from traditional astrobiology regarding life's necessary environment?
astronomyexistenceplanetlifeHabitability