Inspired by Cosmos and Psyche (Tarnas, 2006), we consider the frequency of war during planetary alignments. In particular, we test the hypothesis that there is a correlation between ‘hard’ aspects to the planet Mars and the outbreak of war. Using the data of the Correlates of War project (Sarkees & Wayman, 2010) and the Astrod2 library (Stedall & Wilding, 2022) we calculate the number of wars that start in the periods of alignment of each planet (Conjunctions, Oppositions and Squares within 5° orb) between 1816 and 2007. Compared with chance expectation, the frequency for Mars is highly significant
(p < .0001; r = .12; N = 894).