Often, we call the stages of a star its "life cycle", and I've been thinking about this for a bit.

Stars meet many of the requirements for living organisms: they can consume matter, they can react to stimuli (sort of, does gravity count? e.g. binary systems), they can reproduce (they expel gas clouds on death that can eventually create new stars), they can grow and change size over their lifespan, and they maintain equilibrium (between gravity and radiation pressure from fusion)

What stops stars from being considered living objects?

edit: as it turns out, the formation of new stars after death doesn't really count as reproduction, and gravity shouldn't count as stimuli (a rock experiences gravity too, but it doesn't react to stimuli)

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[–] 1 point 2 days ago

The generalization of the concept of "life" beyond earth-style carbon-based biochemistry is still in active debate. As far as I'm aware, the most consensual definition is the one called "lyfe" (to distinguish from the aforementioned carbon-based chemistry, a concept formulated by Stuart John Bartlett and John L Wong in 2020). It has four characteristics:

  • dissipation : the ability to use/convert energy sources (arguably a thing that stars do)
  • autocatalysis : the ability to grow exponentually (I guess you could argue it happens during the initial star formation before it reaches an equilibrium... Maybe)
  • homeostasis : the ability to compensate for small disturbances in environment (unclear to me what those disturbances and what this adaptation would be in the case of stars)
  • learning : the ability to record, process and adapt to information (no such thing in stars as far as I know)
  • source