Heliosphere
Solar wind
Heliopause
The edge of the solar system where the pressure of the solar wind balances that of the interstellar medium plasma. In other words, the surface boundary that separates the heliosphere from interstellar space. It is estimated to be situated 100 astronomical units or more from the Sun. A bow shock likely forms as the interstellar medium wind approaches the heliosphere and is deflected around the heliosphere, forcing it into a teardrop-shaped structure with a long, comet-like tail.