Launched in 1977, Voyager 1 is now about 12 light-hours or 90 astronomical units (AU) from the Sun, making this spacecraft humanity's most distant ambassador to the cosmos. Well beyond the orbits...

Where does the Sun's influence end? Nobody is sure. Out past the orbits of Neptune and Pluto extends a region named the heliosphere where the Sun's magnetic field and particles from the Solar Wind continue to dominate.