# X-ray Diffraction > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this node within the history and governance of substrate-independent evolution. **Domain:** Scientific Method / Molecular Structure **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition X-ray diffraction infers molecular or crystalline structure from the pattern produced when X-rays scatter through an ordered sample. ## Nexus Context Franklin’s and Wilkins’s DNA work supplied measurements that constrained the double-helix model, making heredity’s material architecture visible through mediated evidence. ## Evidence Boundary A diffraction image is not a direct photograph of a molecule; interpretation depends on experimental preparation, geometry and modeling. ## Relationships [[wiki/Rosalind Franklin|Rosalind Franklin]], [[wiki/Maurice Wilkins|Maurice Wilkins]], [[wiki/Double Helix|Double Helix]], [[wiki/Scientific Inference|Scientific Inference]] ## Sources / Provenance - Franklin and Gosling, _Nature_ 171 (1953); crystallography texts.