"heliopause." YourDictionary, n.d. Web. 07 December 2018. <https://www.yourdictionary.com/heliopause>.
heliopause. (n.d.). Retrieved December 07th, 2018, from https://www.yourdictionary.com/heliopause
The region surrounding the solar system at which pressure from the outgoing solar wind equals the pressure from the interstellar medium (made up mostly of hydrogen and helium),
and the solar wind can penetrate no further. It is considered to be the outer boundary of our solar system.