For the second time in history, a human-made object has reached the space between stars. NASA's Voyager 2 probe has crossed the boundary of the heliosphere and entered interstellar space, where the sun's outflow of material stops and the interstellar medium begins. The spacecraft is slightly more than 11 billion miles (18 billion kilometers) from Earth. Mission operators can still communicate with voyager 2 as it enters this new phase of its journey, but information takes about 16.5 hours to make the journey from the spacecraft to our planet. Its twin, Voyager 1, crossed the boundary and entered interstellar space in 2012.
