• bow shock;
  • slow magnetosonic shock;
  • heliopause;
  • hydrogen wall;
  • outer heliosheath

As our solar system travels through the Milky Way, the Sun's magnetic field interacts with the interstellar magnetic field and the interstellar medium, a mix of dust and gas that permeates interstellar space. At the edge of the heliosphere—the region of the solar system bounded by the Sun's magnetic field—the outflowing solar wind meets the interstellar medium to form the heliopause. On the far side of the heliopause the gas, dust, and cosmic rays of the interstellar medium slow down and pile up to form a structure known as a bow shock.