The heliospheric current sheet is an enormous, wavy structure in the solar system that is created by the Sun's rotating magnetic field. It is a boundary between regions of oppositely directed magnetic field lines, and extends outward from the Sun's equatorial plane to the outer reaches of the solar system. The current sheet is formed by the Sun's differential rotation, which causes its magnetic field to become twisted and distorted over time. This distortion creates two sets of connected loops that form a large-scale, three-dimensional structure known as a Parker spiral. The current sheet acts as a barrier between regions of oppositely directed magnetic fields, and it also serves as an important source of energetic particles that are responsible for aurorae on Earth and other planets.