A galactic cosmic ray cavity in Earth-Moon space

In regions of the solar system distant from planetary magnetic fields, galactic cosmic rays (GCRs) have generally been assumed to be uniformly distributed throughout interplanetary space. However, our analysis of data from the Chang’E-4 lander revealed a region of reduced GCR flux in the pre-noon sector of the lunar orbit. Further investigation suggests the presence of an energetic particle cavity, formed by the Earth’s magnetic field acting as an obstacle to GCR propagation. This cavity indicates that the influence of Earth’s magnetic field within the space environment extends unexpectedly up to and far beyond lunar orbit. This discovery offers the potential to avoid high radiation levels during future lunar exploration and deep-space missions.