Voyager 1 reaches interstellar space

NASA's Voyager 1 spacecraft has finally reached interstellar space, the space between stars. NASA had been reticent so far in declaring this transition as the data and analysis needed to make this claim was not available. The team needed more data on plasma, the densest and slowest moving of charged particles in space. This plasma is a marker to establish whether Voyager 1 is inside the heliosphere, which is inflated by plasma that streams outward from our sun, or in interstellar space and surrounded by material ejected by the explosion of nearby giant stars millions of years ago. The data showed that the Voyager finally moved into the interstellar space on August 25, says NASA. The data has been analysed in a paper published in the journal Science.