Voyager 1 Has Left the Solar System

Voyager 1 has officially left the building! Image Credit: NASA/JPL-Caltech

A new space milestone has just occurred, or occurred around August 2012.  The Voyager 1 space probe that was launched on September 5, 1977 has finally left the solar system.  Thirty five years after its launch the audacious probe enters a new stage in its mission, exploring the region of space outside of the Sun’s influence.

The Sun’s influence in space extends way beyond the orbit of Neptune.  We know that beyond the inner planets lies the Kuiper Belt which is home to Pluto and many, many other dwarf planets.  Finally at about 18 billion kilometers from the Sun and four times the distance between the Sun and Neptune, is a region known as the heliopause.  The heliopause is the region where the solar wind from the Sun collides with the interstellar medium, a collection of particles which is the collection of gas, dust, and cosmic rays.  The solar particles are so dilute once it reaches the interstellar medium that the heliopause is considered the end of the Sun’s influence (although its gravity extends well beyond the heliopause to the Oort Cloud).

A new paper that has been published confirms the conclusions that were drawn about the solar wind particles back in December.  Data from the probe showed that the number of subatomic particles coming from the Sun dropped dramatically sometime around August 2012 while the number of cosmic rays from the interstellar medium spiked.  While it’s not exactly new news, it still is exciting to think about.  There is now a man-made object outside of the solar system and is still able to communicate with us 18 billion kilometers away.

Eventually the plutonium inside of Voyager will stop producing electricity and communications will cease.  At that point, the probe will continue to sail in the direction of the galactic center.  There is an estimated 10-15 years of power left on the probe so we need to enjoy it while it lasts.  It will be a long time before human travelers can journey this far from our home, but we’ll do it one day.