Dust‑Based Crystalline Life: A Probabilistic Framework for Non‑Biochemical Astrobiology

Conventional searches for extraterrestrial life focus on carbon‑based, water‑dependent biology on planetary surfaces. Yet the dominant physical environments in galaxies are not planets but dust‑rich regions such as molecular clouds, protoplanetary disks, and debris disks. Here we explore the plausibility that slow, dust‑based crystalline life could emerge in such environments.

We construct a simple probabilistic framework—analogous in spirit to the Drake equation but adapted to dust rather than planets—using only broad astrophysical properties of the Milky Way. Even under pessimistic assumptions, the expected number of independent crystalline‑life ecosystems is non‑negligible, potentially on the order of hundreds per galaxy.

This perspective naturally complements the Rare Earth hypothesis: if Earth‑like planets are rare, second‑generation outcomes of earlier dust‑phase processes, then Earth‑like biology may be correspondingly rare even if life in a broader physical sense is not.

When extended to the observable universe, the model suggests that crystalline life, if physically possible, may be widespread yet extremely difficult to detect using biology‑centric search strategies.