This paper analyses Robert Hooke’s effort to provide empirical support for Nicolaus Copernicus’ theory, focusing on his work An attempt to prove the motion of the Earth from observations (1674). Hooke’s Attempt is historically significant for three main reasons: The first and better known is the fact that Hooke presents relevant assumptions for a theory of gravitation. The second and third reasons, which are less often discussed, are the fact that Hooke presents the cosmological debate in seventeenth-century England and proposes an experimentum crucis capable of experimentally proving the Copernican hypothesis: the measurement of the parallax of a fixed star. Although Hooke failed to obtain a parallax measurement, his contribution is significant because it represents an attempt to provide empirical support for Copernicus’ theory.