M81 and M82 form a striking interacting pair 12 million light-years away. Gravitational disturbance from M81 has triggered a ferocious burst of star formation in M82, the Cigar Galaxy, at a rate roughly ten times that of the Milky Way. The resulting supernovae drive a dramatic superwind of hot gas that erupts perpendicular to M82’s disc, visible here as diffuse red filaments of hydrogen.