The heliopause is the final known boundary between the heliosphere and the interstellar space that is filled with material, especially plasma, not from the Earth's own star, the Sun, but from other stars. Even so, just outside the heliosphere (i.e. the "solar bubble") there is a transitional region, as detected by "Voyager 1". Just as some interstellar pressure was detected as early as 2004, some of the Sun's material seeps into the interstellar medium. The heliosphere is thought to reside in the Local Interstellar Cloud inside the Local Bubble, which is a region in the Orion Arm of the Milky Way Galaxy.