The constant, omnidirectional hail of cosmic rays that stream through the Solar System from the galaxy beyond may not be as uniform as we thought. According to China's Chang'e 4 lander on the far side of the Moon , there's a strange 'cavity' in the cosmic ray flux between the Earth and Moon that appears when the two bodies line up in just the right way. It's a discovery that suggests galactic cosmic rays are not as evenly distributed as we had assumed, possibly opening opportunities for space