The Voyager 1 probe is currently 119 Astronomical Units (AU) distant from the sun and is traveling at about 3½ AU/yr. 1 AU corresponds to the mean distance between the Earth and the Sun. At 17.8 billion kilometers away, the Voyager 1 craft is the most distant man-made object ever to explore the cosmos. The distances involved are so vast that it can be difficult to visualize the scale of this technological achievement. Here is one figure that really brought home the sense of distance for me: traveling at the speed of light, it would still take 16.5 hours to reach Voyager 1 from Earth.

NASA scientists believe that Voyager 1 will officially traverse the outer boundary of our solar system some time in the next several months. The spacecraft is currently in a region known as the “heliosheath”, the outermost layer of the Solar System, where the solar wind, which travels at about 1 million miles per hour, is being slowed down and meeting the interstellar wind. Nasa scientists believe this indicates the imminent entry of Voyager 1 into the interstellar region, although the exact position of the boundary is still unknown.

The Voyagers have enough electrical power and thruster fuel to operate at least until 2020. By that time, Voyager 1 will be 19.9 billion kilometers from the Sun. Eventually, the Voyager craft will pass by other stars. In about 40,000 years, Voyager 1 will drift within 1.6 light years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis. In approximately 296,000 years, Voyager 2 will pass 4.3 light years from Sirius, the brightest star in the sky.