(6 September 2013) The flow of interstellar gas and dust through the solar system was thought to be unvarying, but Frisch et al. (p. 1080) show that there has been a significant variation of the direction of the flow of interstellar helium through the solar system over the past 40 years. The data, collected by 10 different spacecraft over much of the space age, hint of changes rather than constancy in the solar system‘s galactic environment.