The Acta Universi hypothesis provides the first strict quantitative distinction in the history ofastronomy between dead and living exoplanets in terms of the entropy of thought forms. Aliving planet is an object with entropy s_Θ > 10⁴⁰ bps, while a dead planet is < 103⁵ bps. Thisdifference is 5-15 orders of magnitude (!) and will be reliably detected by instruments of the 2030s (James Webb, LUVOIR, Habitable Worlds Observatory).
Dmitry Yashchenko (Sun,) studied this question.