It is a widespread view that Marx did not apply dialectics to nature, and that Engels’s writings on this subject are a distortion of his outlook. This paper examines Marx’s discussion of elliptical motion and some other physical phenomena, and shows that he did indeed find contradictions and oppositions in nature, and thus recognised a dialectics of nature. In addition to analysing relevant passages in Marx’s texts, his study of the physics and mathematics of elliptical motion is reviewed and compared (...) with Hegel’s position. Marx’s conception of how dialectical contradictions are resolved is reviewed in order to interpret his claim that the contradiction in elliptical motion is ‘solved’ but not ‘overcome’ by that motion. Textual evidence is presented that Marx regarded ‘real contradictions’ as resolved only by ‘development’, a process in which the conflict between the opposing sides of the contradiction becomes more intense. The consequences of this interpretation for Marx’s analysis of elliptical motion are explored, and some alternative interpretations are discussed. (shrink)