We know the solar wind has a pressure and close to the Sun, the solar wind can easily push the interstellar medium away from the Sun. But further away from the Sun, the pressure from the interstellar medium is strong enough to slow down and eventually stop the flow of solar wind from traveling into its surroundings. The entire area or bubble inside the boundary of the solar system is called the Heliosphere. Scientists believe that the closest parts of the Heliosphere are 90 times farther away than the distance between the Earth and Sun. That's three times as far as Pluto.
Ingredients of the Heliosphere are knows as the Bow Shock, Heliopause, Heliosheat and Terminatin Shock.
Bow Shock
The Bow Shock is formed in front of the Heliosphere, as the Sun moves through the interstellar medium. This can be compared what happens at the prow of a boat. Depending of the speed of the Sun traveling into our galaxy it's either a Bow Shock or Bow Wave.
Heliopause
The area where the solar wind's strenght is no longer great enough to push back the interstellar medium is called the Heliopause. It's is often considered to be the outer border of the solar system.
Termination shock
The area where the speed of the solar wind becomes slower than the speed of sound is called the Termination Shock.
The zone between the Termination Shock and the Heliopause is called the Heliosheath.
