Alexandre Champagne-Ruel and colleagues decided to test exactly that. The team built a model to examine how transport dynamics, such as diffusion, combined with network topology — the pattern of connections within a system — shape how molecular complexity is distributed when life is entirely absent.

What did the model show?

The researchers found that the answer is a qualified "yes, but not enough."

Ordered spatial structures, such as regular lattices, did shift abiotic assembly indices upward compared with a randomized control environment. Structure alone, in other words, does nudge complexity higher.

But the effect came with a catch. The upward shift was most pronounced precisely under conditions that are unlikely to generate high-complexity molecules in the first place. Where complex molecules could actually form, the spatial-structure boost faded. The environments best at inflating the numbers were the ones least capable of producing the molecules that would fool a life-detection instrument.

According to the authors, the findings help define the boundaries within which abiotic, spatially structured chemistry operates. That boundary-drawing has two practical payoffs: it supports the reliability of life detection based on assembly indices, and it tells mission designers how to build future instruments and sampling strategies that minimize false positives.

What does this mean for future missions?

For missions targeting potentially habitable worlds — Mars, Europa, Enceladus, or beyond — the result is largely reassuring. A high assembly index measured in a sample remains a strong indicator that something lifelike produced it, even if the sample comes from a porous, chemically structured rock.

The study also carries a laboratory message. According to the authors, the work may provide design constraints for future prebiotic chemistry experiments — efforts to produce lifelike systems from scratch in the lab. Researchers attempting to cook up the origins of life in glassware can now account for how their reaction vessels' spatial architecture might, or might not, shape the complexity of what emerges.

What are the limits of the study?

Some caution is warranted. The results come from a model, not from direct analysis of rock samples or planetary material. Models capture the transport and network physics the researchers chose to include; real geological settings may hold surprises the model does not.

The findings also describe tendencies — structure raises indices under some conditions, not others — rather than an absolute rule. Mission planners will still need to interpret assembly-index measurements in the context of each sample site.

Still, the core takeaway stands. The most famous false-positive worry for molecular-complexity biosignatures — that dead but structured environments could impersonate life — appears weaker than feared, and now comes with quantified boundaries.

The bottom line

Molecular complexity remains a credible universal signature of life. Spatial structure in the environment can nudge abiotic chemistry toward higher assembly indices, but the effect concentrates in conditions that cannot build truly complex molecules. Future missions can rely on the metric, and future prebiotic experiments can design around the newly mapped limits.