The outer boundary of the heliosheath is called the heliopause, which is where the spacecraft are headed now. This is the region where the Sun's influence begins to decrease and interstellar space can be detected. "Voyager 1" is escaping the Solar System at the speed of 3.6 AU per year 35° north of the ecliptic in the general direction of the solar apex in Hercules, while "Voyager 2"s speed is about 3.3 AU per year, heading 48° south of the ecliptic. The Voyager spacecraft will eventually go on to the stars. In about 40,000 years, "Voyager 1" will be within 1.6 light years (ly) of AC+79 3888, also known as Gliese 445, which is approaching the Sun. In 40,000 years "Voyager 2" will be within 1.7 ly of Ross 248 (another star which is approaching the Sun) and in 296,000 years it will pass within 4.6 ly of Sirius which is the brightest star in the night sky.